In WiFi is there any standard convention for the polarity of a helical
antenna. I am building a 40 turn unit and wanted to know whether I
should build it right or left handed.
Yes I know this will only matter when trying to connect with other
systems that use circular polarity.
>In WiFi is there any standard convention for the polarity of a helical
>antenna.
The do it thyself defacto standard was established by the AO40,
Inmarsat, and various WX satellites. All are right hand circular
polarization for the ground station.
Be careful if you build a helical feed for a dish or other reflector
antenna. The reflection changes the sense, so a dish would need a
left hand circular polarized feed.
>I am building a 40 turn unit and wanted to know whether I
>should build it right or left handed.
Right hand.
>Yes I know this will only matter when trying to connect with other
>systems that use circular polarity.
On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
> In WiFi is there any standard convention for the polarity of a helical
> antenna. I am building a 40 turn unit and wanted to know whether I
> should build it right or left handed.
>
> Yes I know this will only matter when trying to connect with other
> systems that use circular polarity.
>
> Jimmie
Please post how it works out. Also, have you considered building a 4
10 turn helix (heli?) and run in parallel. That gets around the
matching issue.
On Jul 29, 11:47*pm, m...@sushi.com wrote:
> On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > In WiFi is there any standard convention for the polarity of a helical
> > antenna. I am building a 40 turn unit and wanted to know whether I
> > should build it right or left handed.
>
> > Yes I know this will only matter when trying to connect with other
> > systems that use circular polarity.
>
> > Jimmie
>
> Please post how it works out. Also, have you considered building a 4
> 10 turn helix (heli?) and run in parallel. That gets around the
> matching issue.
Yes, I thought about that but I have plans for the 40 turn unit
including the matching device. Also I have access to a Network
Analyzer and S pararamter test set for tuning it up. I think building
the matching network may be easier than build a phasing harness for 4
Helix antennas. However I have never done this before so plans may
change. Who knows, if things work out OK I may build a 4 X 40 turn
device.
On Jul 30, 1:57*pm, jimmi...@gmail.com wrote:
> On Jul 29, 11:47*pm, m...@sushi.com wrote:
>
> > On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > > In WiFi is there any standard convention for the polarity of a helical
> > > antenna. I am building a 40 turn unit and wanted to know whether I
> > > should build it right or left handed.
>
> > > Yes I know this will only matter when trying to connect with other
> > > systems that use circular polarity.
>
> > > Jimmie
>
> > Please post how it works out. Also, have you considered building a 4
> > 10 turn helix (heli?) and run in parallel. That gets around the
> > matching issue.
>
> Yes, I thought about that but I have plans for the 40 turn unit
> including the matching device. Also I have access to a Network
> Analyzer and S pararamter test set for tuning it up. I think building
> the matching network may be easier than build a phasing harness for 4
> Helix antennas. However I have never done this before so plans may
> change. Who knows, if things work out OK I may build a 4 X 40 turn
> device.
>
> Jimmie
My guess is paralleling the 4 helix antennas would have a broader
bandwidth than the impedance matched solution. Broadband is good in
the sense that it allows for more error in the construction.
On Jul 31, 1:12*am, m...@sushi.com wrote:
> On Jul 30, 1:57*pm, jimmi...@gmail.com wrote:
>
>
>
>
>
> > On Jul 29, 11:47*pm, m...@sushi.com wrote:
>
> > > On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > > > In WiFi is there any standard convention for the polarity of a helical
> > > > antenna. I am building a 40 turn unit and wanted to know whether I
> > > > should build it right or left handed.
>
> > > > Yes I know this will only matter when trying to connect with other
> > > > systems that use circular polarity.
>
> > > > Jimmie
>
> > > Please post how it works out. Also, have you considered building a 4
> > > 10 turn helix (heli?) and run in parallel. That gets around the
> > > matching issue.
>
> > Yes, I thought about that but I have plans for the 40 turn unit
> > including the matching device. Also I have access to a Network
> > Analyzer and S pararamter test set for tuning it up. I think building
> > the matching network may be easier than build a phasing harness for 4
> > Helix antennas. However I have never done this before so plans may
> > change. Who knows, if things work out OK I may build a 4 X 40 turn
> > device.
>
> > Jimmie
>
> My guess is paralleling the 4 helix antennas would have a broader
> bandwidth than the impedance matched solution. Broadband is good in
> the sense that it allows for more error in the construction.- Hide quotedtext -
>
> - Show quoted text -
Usually paralelling(stacking) antennas means a narrower bandwidth.
This statement assumes all the stacked antennas are identical.
On Aug 1, 4:33*pm, jimmi...@gmail.com wrote:
> On Jul 31, 1:12*am, m...@sushi.com wrote:
>
>
>
>
>
> > On Jul 30, 1:57*pm, jimmi...@gmail.com wrote:
>
> > > On Jul 29, 11:47*pm, m...@sushi.com wrote:
>
> > > > On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > > > > In WiFi is there any standard convention for the polarity of a helical
> > > > > antenna. I am building a 40 turn unit and wanted to know whether I
> > > > > should build it right or left handed.
>
> > > > > Yes I know this will only matter when trying to connect with other
> > > > > systems that use circular polarity.
>
> > > > > Jimmie
>
> > > > Please post how it works out. Also, have you considered building a 4
> > > > 10 turn helix (heli?) and run in parallel. That gets around the
> > > > matching issue.
>
> > > Yes, I thought about that but I have plans for the 40 turn unit
> > > including the matching device. Also I have access to a Network
> > > Analyzer and S pararamter test set for tuning it up. I think building
> > > the matching network may be easier than build a phasing harness for 4
> > > Helix antennas. However I have never done this before so plans may
> > > change. Who knows, if things work out OK I may build a 4 X 40 turn
> > > device.
>
> > > Jimmie
>
> > My guess is paralleling the 4 helix antennas would have a broader
> > bandwidth than the impedance matched solution. Broadband is good in
> > the sense that it allows for more error in the construction.- Hide quoted text -
>
> > - Show quoted text -
>
> Usually paralelling(stacking) antennas means a narrower bandwidth.
> This statement assumes all the stacked antennas are identical.
>
> Jimmie- Hide quoted text -
>
> - Show quoted text -
This should be of interest to anyo one wanting to build a helix
antena.
On Aug 1, 1:33*pm, jimmi...@gmail.com wrote:
> On Jul 31, 1:12*am, m...@sushi.com wrote:
>
>
>
> > On Jul 30, 1:57*pm, jimmi...@gmail.com wrote:
>
> > > On Jul 29, 11:47*pm, m...@sushi.com wrote:
>
> > > > On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > > > > In WiFi is there any standard convention for the polarity of a helical
> > > > > antenna. I am building a 40 turn unit and wanted to know whether I
> > > > > should build it right or left handed.
>
> > > > > Yes I know this will only matter when trying to connect with other
> > > > > systems that use circular polarity.
>
> > > > > Jimmie
>
> > > > Please post how it works out. Also, have you considered building a 4
> > > > 10 turn helix (heli?) and run in parallel. That gets around the
> > > > matching issue.
>
> > > Yes, I thought about that but I have plans for the 40 turn unit
> > > including the matching device. Also I have access to a Network
> > > Analyzer and S pararamter test set for tuning it up. I think building
> > > the matching network may be easier than build a phasing harness for 4
> > > Helix antennas. However I have never done this before so plans may
> > > change. Who knows, if things work out OK I may build a 4 X 40 turn
> > > device.
>
> > > Jimmie
>
> > My guess is paralleling the 4 helix antennas would have a broader
> > bandwidth than the impedance matched solution. Broadband is good in
> > the sense that it allows for more error in the construction.- Hide quoted text -
>
> > - Show quoted text -
>
> Usually paralelling(stacking) antennas means a narrower bandwidth.
> This statement assumes all the stacked antennas are identical.
>
> Jimmie
I see no reason for stacked antennas to have a narrower bandwidth. Can
you elaborate?
On Aug 1, 5:09*pm, jimmi...@gmail.com wrote:
> On Aug 1, 4:33*pm, jimmi...@gmail.com wrote:
>
>
>
> > On Jul 31, 1:12*am, m...@sushi.com wrote:
>
> > > On Jul 30, 1:57*pm, jimmi...@gmail.com wrote:
>
> > > > On Jul 29, 11:47*pm, m...@sushi.com wrote:
>
> > > > > On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > > > > > In WiFi is there any standard convention for the polarity of a helical
> > > > > > antenna. I am building a 40 turn unit and wanted to know whether I
> > > > > > should build it right or left handed.
>
> > > > > > Yes I know this will only matter when trying to connect with other
> > > > > > systems that use circular polarity.
>
> > > > > > Jimmie
>
> > > > > Please post how it works out. Also, have you considered building a 4
> > > > > 10 turn helix (heli?) and run in parallel. That gets around the
> > > > > matching issue.
>
> > > > Yes, I thought about that but I have plans for the 40 turn unit
> > > > including the matching device. Also I have access to a Network
> > > > Analyzer and S pararamter test set for tuning it up. I think building
> > > > the matching network may be easier than build a phasing harness for4
> > > > Helix antennas. However I have never done this before so plans may
> > > > change. Who knows, if things work out OK I may build a 4 X 40 turn
> > > > device.
>
> > > > Jimmie
>
> > > My guess is paralleling the 4 helix antennas would have a broader
> > > bandwidth than the impedance matched solution. Broadband is good in
> > > the sense that it allows for more error in the construction.- Hide quoted text -
>
> > > - Show quoted text -
>
> > Usually paralelling(stacking) antennas means a narrower bandwidth.
> > This statement assumes all the stacked antennas are identical.
>
> > Jimmie- Hide quoted text -
>
> > - Show quoted text -
>
> This should be of interest to anyo one wanting to build a helix
> antena.
>
> http://www.qsl.net/ve3cvg/antennas/2400/
>
> Jimmie
When I build antennas, I try to use all copper if I can. Otherwise,
you get a battery connecting Al to copper. I'm not sure about
connecting copper to galvanized. I've built a few log periodics (VHF/
UHF) and used that gunk (OK, not a technical term) used with Al
wiring. Still, it deteriorates with time. Consider using copper wire.
Have you considered the biquad? Unless you have circular polarization
on both ends, you will lose 3db when interfacing with linear polarized
antennas, so 16db becomes 13db, which is close to the biquad.
I guess a long helix would be better for snooping purposes since not
everyone is vertically polarized.
On Fri, 1 Aug 2008 23:18:03 -0700 (PDT), miso@sushi.com wrote:
>On Aug 1, 1:33*pm, jimmi...@gmail.com wrote:
>> Usually paralelling(stacking) antennas means a narrower bandwidth.
>> This statement assumes all the stacked antennas are identical.
>> Jimmie
>I see no reason for stacked antennas to have a narrower bandwidth. Can
>you elaborate?
If your definition of bandwidth is the frequency between the -3dB
points, stacking two isolated resonant antennas together results in
exactly the same bandwidth as one antenna. An easier way to see this
is if the two antennas were simple parallel tuned circuits acting as a
bandpass filter. If you connect them together, using some means of
coupling that is critically coupled (i.e. maximum power tranfer), the
resultant circuit has exactly the same bandwidth. If you plot it on a
piece of graph paper, you could stack a dozen critically coupled tuned
circuits together and get exactly the same -3dB bandwidth. Obviously
the skirt factor and bandwidth at other refrence points will be
narrower as you add sections.
Of course, such things fall apart when dealing with real world devices
and antennas. Two stacked antennas will couple to each other, causing
difficulties with such simplistic explanations. The traditional 2x2
array of helixes heavily couple to each other, especially since
they're the same sense. Anyway, the only way to get it right is to
fire up your favorite NEC antenna modeling program, which takes such
things into consideration. 4NEC2 includes a helix generator.
Specifically for a helix, the approximate -3dB bandwidth for a single
helix is roughly equal to the center frequency. In other words, if
you cut a helix for 2.4GHz, it will be usable from 1.2 to 3.6Ghz.
Stacking 4 of these together will theoretically not reduce this
bandwidth, but in reality, will reduce it somewhat. I don't think
operation in an 83.5MHz band is going to be affected with an antenna
with a 1 or 2Ghz bandwidth.
On Aug 2, 8:58*am, Jeff Liebermann <je...@cruzio.com> wrote:
> On Fri, 1 Aug 2008 23:18:03 -0700 (PDT), m...@sushi.com wrote:
> >On Aug 1, 1:33*pm, jimmi...@gmail.com wrote:
> >> Usually paralelling(stacking) antennas means a narrower bandwidth.
> >> This statement assumes all the stacked antennas are identical.
> >> Jimmie
> >I see no reason for stacked antennas to have a narrower bandwidth. Can
> >you elaborate?
>
> If your definition of bandwidth is the frequency between the -3dB
> points, stacking two isolated resonant antennas together results in
> exactly the same bandwidth as one antenna. *An easier way to see this
> is if the two antennas were simple parallel tuned circuits acting as a
> bandpass filter. *If you connect them together, using some means of
> coupling that is critically coupled (i.e. maximum power tranfer), the
> resultant circuit has exactly the same bandwidth. *If you plot it on a
> piece of graph paper, you could stack a dozen critically coupled tuned
> circuits together and get exactly the same -3dB bandwidth. *Obviously
> the skirt factor and bandwidth at other refrence points will be
> narrower as you add sections.
>
> Of course, such things fall apart when dealing with real world devices
> and antennas. *Two stacked antennas will couple to each other, causing
> difficulties with such simplistic explanations. *The traditional 2x2
> array of helixes heavily couple to each other, especially since
> they're the same sense. *Anyway, the only way to get it right is to
> fire up your favorite NEC antenna modeling program, which takes such
> things into consideration. *4NEC2 includes a helix generator.
>
> Specifically for a helix, the approximate -3dB bandwidth for a single
> helix is roughly equal to the center frequency. *In other words, if
> you cut a helix for 2.4GHz, it will be usable from 1.2 to 3.6Ghz.
> Stacking 4 of these together will theoretically not reduce this
> bandwidth, but in reality, will reduce it somewhat. *I don't think
> operation in an 83.5MHz band is going to be affected with an antenna
> with a 1 or 2Ghz bandwidth.
>
> --
> Jeff Liebermann * * je...@cruzio.com
> 150 Felker St #D * *http://www.LearnByDestroying.com
> Santa Cruz CA 95060http://802.11junk.com
> Skype: JeffLiebermann * * AE6KS * *831-336-2558
How about the impedance matching scheme? That must narrow the
bandwidth. Also your comments on mixing Al and Cu?
On Aug 2, 2:18*am, m...@sushi.com wrote:
> On Aug 1, 1:33*pm, jimmi...@gmail.com wrote:
>
>
>
>
>
> > On Jul 31, 1:12*am, m...@sushi.com wrote:
>
> > > On Jul 30, 1:57*pm, jimmi...@gmail.com wrote:
>
> > > > On Jul 29, 11:47*pm, m...@sushi.com wrote:
>
> > > > > On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > > > > > In WiFi is there any standard convention for the polarity of a helical
> > > > > > antenna. I am building a 40 turn unit and wanted to know whether I
> > > > > > should build it right or left handed.
>
> > > > > > Yes I know this will only matter when trying to connect with other
> > > > > > systems that use circular polarity.
>
> > > > > > Jimmie
>
> > > > > Please post how it works out. Also, have you considered building a 4
> > > > > 10 turn helix (heli?) and run in parallel. That gets around the
> > > > > matching issue.
>
> > > > Yes, I thought about that but I have plans for the 40 turn unit
> > > > including the matching device. Also I have access to a Network
> > > > Analyzer and S pararamter test set for tuning it up. I think building
> > > > the matching network may be easier than build a phasing harness for4
> > > > Helix antennas. However I have never done this before so plans may
> > > > change. Who knows, if things work out OK I may build a 4 X 40 turn
> > > > device.
>
> > > > Jimmie
>
> > > My guess is paralleling the 4 helix antennas would have a broader
> > > bandwidth than the impedance matched solution. Broadband is good in
> > > the sense that it allows for more error in the construction.- Hide quoted text -
>
> > > - Show quoted text -
>
> > Usually paralelling(stacking) antennas means a narrower bandwidth.
> > This statement assumes all the stacked antennas are identical.
>
> > Jimmie
>
> I see no reason for stacked antennas to have a narrower bandwidth. Can
> you elaborate?- Hide quoted text -
>
> - Show quoted text -
Sorry I was thinking of bandwidth in terms of frequency versus VSWR.
This is usally the limiting factor as gain bandwidth is almost always
much broader
than VSWR bandwidth.
As of yet I dont know whether this will be a serious consequence or
not concerning the helix antenna.
My plan is to build the antenna and tune it for greatest field
strength
A few years ago I stacked 2 2 meter 6 element quad antennas. I had
plans to stack 4 but didnt do it because
of the VSWR excursion from one end of the band to the other.
My solidstate amp was not fond of the 2 to 1 VSWR near the band edges.
In this situation the VSWR bandwidth of 2 antennas was less than 1
antenna and with 4 antennas it was even less.
I am sure the array would have still exhibited considerable gain if I
had a way to readily correct for the impedance changes seen by my
amplifier.
On Aug 2, 8:58*pm, jimmi...@gmail.com wrote:
> On Aug 2, 2:18*am, m...@sushi.com wrote:
>
>
>
> > On Aug 1, 1:33*pm, jimmi...@gmail.com wrote:
>
> > > On Jul 31, 1:12*am, m...@sushi.com wrote:
>
> > > > On Jul 30, 1:57*pm, jimmi...@gmail.com wrote:
>
> > > > > On Jul 29, 11:47*pm, m...@sushi.com wrote:
>
> > > > > > On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > > > > > > In WiFi is there any standard convention for the polarity of a helical
> > > > > > > antenna. I am building a 40 turn unit and wanted to know whether I
> > > > > > > should build it right or left handed.
>
> > > > > > > Yes I know this will only matter when trying to connect with other
> > > > > > > systems that use circular polarity.
>
> > > > > > > Jimmie
>
> > > > > > Please post how it works out. Also, have you considered building a 4
> > > > > > 10 turn helix (heli?) and run in parallel. That gets around the
> > > > > > matching issue.
>
> > > > > Yes, I thought about that but I have plans for the 40 turn unit
> > > > > including the matching device. Also I have access to a Network
> > > > > Analyzer and S pararamter test set for tuning it up. I think building
> > > > > the matching network may be easier than build a phasing harness for 4
> > > > > Helix antennas. However I have never done this before so plans may
> > > > > change. Who knows, if things work out OK I may build a 4 X 40 turn
> > > > > device.
>
> > > > > Jimmie
>
> > > > My guess is paralleling the 4 helix antennas would have a broader
> > > > bandwidth than the impedance matched solution. Broadband is good in
> > > > the sense that it allows for more error in the construction.- Hide quoted text -
>
> > > > - Show quoted text -
>
> > > Usually paralelling(stacking) antennas means a narrower bandwidth.
> > > This statement assumes all the stacked antennas are identical.
>
> > > Jimmie
>
> > I see no reason for stacked antennas to have a narrower bandwidth. Can
> > you elaborate?- Hide quoted text -
>
> > - Show quoted text -
>
> Sorry I was thinking of bandwidth in terms of frequency versus VSWR.
> This is usally the limiting factor as gain bandwidth is almost always
> much broader
> than VSWR bandwidth.
> As of yet I dont know whether this will be a serious consequence or
> not *concerning the helix antenna.
>
> My plan is to build the antenna and tune it for greatest field
> strength
>
> A few years ago I stacked 2 2 meter 6 element quad antennas. I had
> plans to stack 4 but didnt do it because
> of the VSWR excursion from one end of the band to the other.
> My solidstate amp was not fond of the 2 to 1 VSWR near the band edges.
>
> In this situation the VSWR bandwidth of 2 antennas was less than 1
> antenna and with 4 antennas it was even less.
> I am sure the array would have still exhibited considerable gain if I
> had a way to readily correct for the impedance changes seen by my
> amplifier.
>
> Jimmie
I wonder if the VSWR effects were due to coupling between antennas?
On Aug 3, 11:49*pm, m...@sushi.com wrote:
> On Aug 2, 8:58*pm, jimmi...@gmail.com wrote:
>
>
>
>
>
> > On Aug 2, 2:18*am, m...@sushi.com wrote:
>
> > > On Aug 1, 1:33*pm, jimmi...@gmail.com wrote:
>
> > > > On Jul 31, 1:12*am, m...@sushi.com wrote:
>
> > > > > On Jul 30, 1:57*pm, jimmi...@gmail.com wrote:
>
> > > > > > On Jul 29, 11:47*pm, m...@sushi.com wrote:
>
> > > > > > > On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > In WiFi is there any standard convention for the polarity of a helical
> > > > > > > > antenna. I am building a 40 turn unit and wanted to know whether I
> > > > > > > > should build it right or left handed.
>
> > > > > > > > Yes I know this will only matter when trying to connect with other
> > > > > > > > systems that use circular polarity.
>
> > > > > > > > Jimmie
>
> > > > > > > Please post how it works out. Also, have you considered building a 4
> > > > > > > 10 turn helix (heli?) and run in parallel. That gets around the
> > > > > > > matching issue.
>
> > > > > > Yes, I thought about that but I have plans for the 40 turn unit
> > > > > > including the matching device. Also I have access to a Network
> > > > > > Analyzer and S pararamter test set for tuning it up. I think building
> > > > > > the matching network may be easier than build a phasing harnessfor 4
> > > > > > Helix antennas. However I have never done this before so plans may
> > > > > > change. Who knows, if things work out OK I may build a 4 X 40 turn
> > > > > > device.
>
> > > > > > Jimmie
>
> > > > > My guess is paralleling the 4 helix antennas would have a broader
> > > > > bandwidth than the impedance matched solution. Broadband is good in
> > > > > the sense that it allows for more error in the construction.- Hide quoted text -
>
> > > > > - Show quoted text -
>
> > > > Usually paralelling(stacking) antennas means a narrower bandwidth.
> > > > This statement assumes all the stacked antennas are identical.
>
> > > > Jimmie
>
> > > I see no reason for stacked antennas to have a narrower bandwidth. Can
> > > you elaborate?- Hide quoted text -
>
> > > - Show quoted text -
>
> > Sorry I was thinking of bandwidth in terms of frequency versus VSWR.
> > This is usally the limiting factor as gain bandwidth is almost always
> > much broader
> > than VSWR bandwidth.
> > As of yet I dont know whether this will be a serious consequence or
> > not *concerning the helix antenna.
>
> > My plan is to build the antenna and tune it for greatest field
> > strength
>
> > A few years ago I stacked 2 2 meter 6 element quad antennas. I had
> > plans to stack 4 but didnt do it because
> > of the VSWR excursion from one end of the band to the other.
> > My solidstate amp was not fond of the 2 to 1 VSWR near the band edges.
>
> > In this situation the VSWR bandwidth of 2 antennas was less than 1
> > antenna and with 4 antennas it was even less.
> > I am sure the array would have still exhibited considerable gain if I
> > had a way to readily correct for the impedance changes seen by my
> > amplifier.
>
> > Jimmie
>
> I wonder if the VSWR effects were due to coupling between antennas?- Hidequoted text -
>
> - Show quoted text -
I dont know, the antennas came with printouts from NEC antenna
modeling software. One of the parameters given was a diagram of their
capture area. The antennas were place according to this data with
their capture areas just touching. A local ham who is very much into
antenna modeling verified the data that came with the antennas. At the
time I was surprised by the reccomenced spacing thinking it was
excessive until I discovered that rules saying 1/2 or 5/8 spacing was
not always correct.
On Aug 7, 4:16*pm, jimmi...@gmail.com wrote:
> On Aug 3, 11:49*pm, m...@sushi.com wrote:
>
>
>
>
>
> > On Aug 2, 8:58*pm, jimmi...@gmail.com wrote:
>
> > > On Aug 2, 2:18*am, m...@sushi.com wrote:
>
> > > > On Aug 1, 1:33*pm, jimmi...@gmail.com wrote:
>
> > > > > On Jul 31, 1:12*am, m...@sushi.com wrote:
>
> > > > > > On Jul 30, 1:57*pm, jimmi...@gmail.com wrote:
>
> > > > > > > On Jul 29, 11:47*pm, m...@sushi.com wrote:
>
> > > > > > > > On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > > In WiFi is there any standard convention for the polarityof a helical
> > > > > > > > > antenna. I am building a 40 turn unit and wanted to know whether I
> > > > > > > > > should build it right or left handed.
>
> > > > > > > > > Yes I know this will only matter when trying to connect with other
> > > > > > > > > systems that use circular polarity.
>
> > > > > > > > > Jimmie
>
> > > > > > > > Please post how it works out. Also, have you considered building a 4
> > > > > > > > 10 turn helix (heli?) and run in parallel. That gets aroundthe
> > > > > > > > matching issue.
>
> > > > > > > Yes, I thought about that but I have plans for the 40 turn unit
> > > > > > > including the matching device. Also I have access to a Network
> > > > > > > Analyzer and S pararamter test set for tuning it up. I think building
> > > > > > > the matching network may be easier than build a phasing harness for 4
> > > > > > > Helix antennas. However I have never done this before so plans may
> > > > > > > change. Who knows, if things work out OK I may build a 4 X 40turn
> > > > > > > device.
>
> > > > > > > Jimmie
>
> > > > > > My guess is paralleling the 4 helix antennas would have a broader
> > > > > > bandwidth than the impedance matched solution. Broadband is good in
> > > > > > the sense that it allows for more error in the construction.- Hide quoted text -
>
> > > > > > - Show quoted text -
>
> > > > > Usually paralelling(stacking) antennas means a narrower bandwidth..
> > > > > This statement assumes all the stacked antennas are identical.
>
> > > > > Jimmie
>
> > > > I see no reason for stacked antennas to have a narrower bandwidth. Can
> > > > you elaborate?- Hide quoted text -
>
> > > > - Show quoted text -
>
> > > Sorry I was thinking of bandwidth in terms of frequency versus VSWR.
> > > This is usally the limiting factor as gain bandwidth is almost always
> > > much broader
> > > than VSWR bandwidth.
> > > As of yet I dont know whether this will be a serious consequence or
> > > not *concerning the helix antenna.
>
> > > My plan is to build the antenna and tune it for greatest field
> > > strength
>
> > > A few years ago I stacked 2 2 meter 6 element quad antennas. I had
> > > plans to stack 4 but didnt do it because
> > > of the VSWR excursion from one end of the band to the other.
> > > My solidstate amp was not fond of the 2 to 1 VSWR near the band edges..
>
> > > In this situation the VSWR bandwidth of 2 antennas was less than 1
> > > antenna and with 4 antennas it was even less.
> > > I am sure the array would have still exhibited considerable gain if I
> > > had a way to readily correct for the impedance changes seen by my
> > > amplifier.
>
> > > Jimmie
>
> > I wonder if the VSWR effects were due to coupling between antennas?- Hide quoted text -
>
> > - Show quoted text -
>
> I dont know, the antennas came with printouts from NEC antenna
> modeling software. One of the parameters given was a diagram of their
> capture area. The antennas were place according to this data with
> their capture areas just touching. A local ham who is very much into
> antenna modeling verified the data that came with the antennas. At the
> time I was surprised by the reccomenced spacing thinking it was
> excessive until I discovered that rules saying 1/2 or 5/8 spacing was
> not always correct.- Hide quoted text -
>
> - Show quoted text -
On Aug 7, 1:23*pm, jimmi...@gmail.com wrote:
> On Aug 7, 4:16*pm, jimmi...@gmail.com wrote:
>
>
>
> > On Aug 3, 11:49*pm, m...@sushi.com wrote:
>
> > > On Aug 2, 8:58*pm, jimmi...@gmail.com wrote:
>
> > > > On Aug 2, 2:18*am, m...@sushi.com wrote:
>
> > > > > On Aug 1, 1:33*pm, jimmi...@gmail.com wrote:
>
> > > > > > On Jul 31, 1:12*am, m...@sushi.com wrote:
>
> > > > > > > On Jul 30, 1:57*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > On Jul 29, 11:47*pm, m...@sushi.com wrote:
>
> > > > > > > > > On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > > > In WiFi is there any standard convention for the polarity of a helical
> > > > > > > > > > antenna. I am building a 40 turn unit and wanted to know whether I
> > > > > > > > > > should build it right or left handed.
>
> > > > > > > > > > Yes I know this will only matter when trying to connectwith other
> > > > > > > > > > systems that use circular polarity.
>
> > > > > > > > > > Jimmie
>
> > > > > > > > > Please post how it works out. Also, have you considered building a 4
> > > > > > > > > 10 turn helix (heli?) and run in parallel. That gets around the
> > > > > > > > > matching issue.
>
> > > > > > > > Yes, I thought about that but I have plans for the 40 turn unit
> > > > > > > > including the matching device. Also I have access to a Network
> > > > > > > > Analyzer and S pararamter test set for tuning it up. I think building
> > > > > > > > the matching network may be easier than build a phasing harness for 4
> > > > > > > > Helix antennas. However I have never done this before so plans may
> > > > > > > > change. Who knows, if things work out OK I may build a 4 X 40 turn
> > > > > > > > device.
>
> > > > > > > > Jimmie
>
> > > > > > > My guess is paralleling the 4 helix antennas would have a broader
> > > > > > > bandwidth than the impedance matched solution. Broadband is good in
> > > > > > > the sense that it allows for more error in the construction.-Hide quoted text -
>
> > > > > > > - Show quoted text -
>
> > > > > > Usually paralelling(stacking) antennas means a narrower bandwidth.
> > > > > > This statement assumes all the stacked antennas are identical.
>
> > > > > > Jimmie
>
> > > > > I see no reason for stacked antennas to have a narrower bandwidth.. Can
> > > > > you elaborate?- Hide quoted text -
>
> > > > > - Show quoted text -
>
> > > > Sorry I was thinking of bandwidth in terms of frequency versus VSWR..
> > > > This is usally the limiting factor as gain bandwidth is almost always
> > > > much broader
> > > > than VSWR bandwidth.
> > > > As of yet I dont know whether this will be a serious consequence or
> > > > not *concerning the helix antenna.
>
> > > > My plan is to build the antenna and tune it for greatest field
> > > > strength
>
> > > > A few years ago I stacked 2 2 meter 6 element quad antennas. I had
> > > > plans to stack 4 but didnt do it because
> > > > of the VSWR excursion from one end of the band to the other.
> > > > My solidstate amp was not fond of the 2 to 1 VSWR near the band edges.
>
> > > > In this situation the VSWR bandwidth of 2 antennas was less than 1
> > > > antenna and with 4 antennas it was even less.
> > > > I am sure the array would have still exhibited considerable gain ifI
> > > > had a way to readily correct for the impedance changes seen by my
> > > > amplifier.
>
> > > > Jimmie
>
> > > I wonder if the VSWR effects were due to coupling between antennas?- Hide quoted text -
>
> > > - Show quoted text -
>
> > I dont know, the antennas came with printouts from NEC antenna
> > modeling software. One of the parameters given was a diagram of their
> > capture area. The antennas were place according to this data with
> > their capture areas just touching. A local ham who is very much into
> > antenna modeling verified the data that came with the antennas. At the
> > time I was surprised by the reccomenced spacing thinking it was
> > excessive until I discovered that rules saying 1/2 or 5/8 spacing was
> > not always correct.- Hide quoted text -
>
> > - Show quoted text -
>
> Source of info on stacking antennashttp://www.ifwtech.co.uk/g3sek/stacking/stacking2.htm.
>
> Ian is extremely knowledgable on the *subject.
>
> Jimmie
I could see the stacked yagis interacting. The problem with beam
antennas is from the top and bottom, they more or less look like
dipoles because the driven element is not shielded from those
directions. I never stacked any beams, but if I did, I'd consider
antenna designs that had what amounts to a corner reflector at the
back of each antenna. That would shield the driven element.
I've been trying to DF vertically polarized UHF signals with a yagi. I
find it really hard to find a peak and suspect there is just too much
gain from the dipole as view from top and bottom. I've DFed HF with
loop using the null, and that works very well. The particular UHF
signal is heavily modulated, so the cheap double ducky box doesn't
work.
On Aug 8, 3:56*am, m...@sushi.com wrote:
> On Aug 7, 1:23*pm, jimmi...@gmail.com wrote:
>
>
>
>
>
> > On Aug 7, 4:16*pm, jimmi...@gmail.com wrote:
>
> > > On Aug 3, 11:49*pm, m...@sushi.com wrote:
>
> > > > On Aug 2, 8:58*pm, jimmi...@gmail.com wrote:
>
> > > > > On Aug 2, 2:18*am, m...@sushi.com wrote:
>
> > > > > > On Aug 1, 1:33*pm, jimmi...@gmail.com wrote:
>
> > > > > > > On Jul 31, 1:12*am, m...@sushi.com wrote:
>
> > > > > > > > On Jul 30, 1:57*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > > On Jul 29, 11:47*pm, m...@sushi.com wrote:
>
> > > > > > > > > > On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > > > > In WiFi is there any standard convention for the polarity of a helical
> > > > > > > > > > > antenna. I am building a 40 turn unit and wanted to know whether I
> > > > > > > > > > > should build it right or left handed.
>
> > > > > > > > > > > Yes I know this will only matter when trying to connect with other
> > > > > > > > > > > systems that use circular polarity.
>
> > > > > > > > > > > Jimmie
>
> > > > > > > > > > Please post how it works out. Also, have you consideredbuilding a 4
> > > > > > > > > > 10 turn helix (heli?) and run in parallel. That gets around the
> > > > > > > > > > matching issue.
>
> > > > > > > > > Yes, I thought about that but I have plans for the 40 turn unit
> > > > > > > > > including the matching device. Also I have access to a Network
> > > > > > > > > Analyzer and S pararamter test set for tuning it up. I think building
> > > > > > > > > the matching network may be easier than build a phasing harness for 4
> > > > > > > > > Helix antennas. However I have never done this before so plans may
> > > > > > > > > change. Who knows, if things work out OK I may build a 4 X 40 turn
> > > > > > > > > device.
>
> > > > > > > > > Jimmie
>
> > > > > > > > My guess is paralleling the 4 helix antennas would have a broader
> > > > > > > > bandwidth than the impedance matched solution. Broadband isgood in
> > > > > > > > the sense that it allows for more error in the construction..- Hide quoted text -
>
> > > > > > > > - Show quoted text -
>
> > > > > > > Usually paralelling(stacking) antennas means a narrower bandwidth.
> > > > > > > This statement assumes all the stacked antennas are identical..
>
> > > > > > > Jimmie
>
> > > > > > I see no reason for stacked antennas to have a narrower bandwidth. Can
> > > > > > you elaborate?- Hide quoted text -
>
> > > > > > - Show quoted text -
>
> > > > > Sorry I was thinking of bandwidth in terms of frequency versus VSWR.
> > > > > This is usally the limiting factor as gain bandwidth is almost always
> > > > > much broader
> > > > > than VSWR bandwidth.
> > > > > As of yet I dont know whether this will be a serious consequence or
> > > > > not *concerning the helix antenna.
>
> > > > > My plan is to build the antenna and tune it for greatest field
> > > > > strength
>
> > > > > A few years ago I stacked 2 2 meter 6 element quad antennas. I had
> > > > > plans to stack 4 but didnt do it because
> > > > > of the VSWR excursion from one end of the band to the other.
> > > > > My solidstate amp was not fond of the 2 to 1 VSWR near the band edges.
>
> > > > > In this situation the VSWR bandwidth of 2 antennas was less than 1
> > > > > antenna and with 4 antennas it was even less.
> > > > > I am sure the array would have still exhibited considerable gain if I
> > > > > had a way to readily correct for the impedance changes seen by my
> > > > > amplifier.
>
> > > > > Jimmie
>
> > > > I wonder if the VSWR effects were due to coupling between antennas?- Hide quoted text -
>
> > > > - Show quoted text -
>
> > > I dont know, the antennas came with printouts from NEC antenna
> > > modeling software. One of the parameters given was a diagram of their
> > > capture area. The antennas were place according to this data with
> > > their capture areas just touching. A local ham who is very much into
> > > antenna modeling verified the data that came with the antennas. At the
> > > time I was surprised by the reccomenced spacing thinking it was
> > > excessive until I discovered that rules saying 1/2 or 5/8 spacing was
> > > not always correct.- Hide quoted text -
>
> > > - Show quoted text -
>
> > Source of info on stacking antennashttp://www.ifwtech.co.uk/g3sek/stacking/stacking2.htm.
>
> > Ian is extremely knowledgable on the *subject.
>
> > Jimmie
>
> I could see the stacked yagis interacting. The problem with beam
> antennas is from the top and bottom, they more or less look like
> dipoles because the driven element is not shielded from those
> directions. I never stacked any beams, but if I did, I'd consider
> antenna designs that had what amounts to a corner reflector at the
> back of each antenna. That would shield the driven element.
>
> I've been trying to DF vertically polarized UHF signals with a yagi. I
> find it really hard to find a peak and suspect there is just too much
> gain from the dipole as view from top and bottom. I've DFed HF with
> loop using the null, and that works very well. The particular UHF
> signal is heavily modulated, so the cheap double ducky box doesn't
> work.- Hide quoted text -
>
> - Show quoted text -
I use a "Little L-per" direction finder and sometimes use a Yagi with
a little handheld VHF UHF radio. When I use the YAGI sometimes I turn
it around backwards and search for the null instead of the peak. Also
you need to check the pattern of your yagi. Some can be rather skewed
from what you think they should be.
On Aug 8, 1:20*pm, jimmi...@gmail.com wrote:
> On Aug 8, 3:56*am, m...@sushi.com wrote:
>
>
>
> > On Aug 7, 1:23*pm, jimmi...@gmail.com wrote:
>
> > > On Aug 7, 4:16*pm, jimmi...@gmail.com wrote:
>
> > > > On Aug 3, 11:49*pm, m...@sushi.com wrote:
>
> > > > > On Aug 2, 8:58*pm, jimmi...@gmail.com wrote:
>
> > > > > > On Aug 2, 2:18*am, m...@sushi.com wrote:
>
> > > > > > > On Aug 1, 1:33*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > On Jul 31, 1:12*am, m...@sushi.com wrote:
>
> > > > > > > > > On Jul 30, 1:57*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > > > On Jul 29, 11:47*pm, m...@sushi.com wrote:
>
> > > > > > > > > > > On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > > > > > In WiFi is there any standard convention for the polarity of a helical
> > > > > > > > > > > > antenna. I am building a 40 turn unit and wanted toknow whether I
> > > > > > > > > > > > should build it right or left handed.
>
> > > > > > > > > > > > Yes I know this will only matter when trying to connect with other
> > > > > > > > > > > > systems that use circular polarity.
>
> > > > > > > > > > > > Jimmie
>
> > > > > > > > > > > Please post how it works out. Also, have you considered building a 4
> > > > > > > > > > > 10 turn helix (heli?) and run in parallel. That gets around the
> > > > > > > > > > > matching issue.
>
> > > > > > > > > > Yes, I thought about that but I have plans for the 40 turn unit
> > > > > > > > > > including the matching device. Also I have access to a Network
> > > > > > > > > > Analyzer and S pararamter test set for tuning it up. I think building
> > > > > > > > > > the matching network may be easier than build a phasingharness for 4
> > > > > > > > > > Helix antennas. However I have never done this before so plans may
> > > > > > > > > > change. Who knows, if things work out OK I may build a 4 X 40 turn
> > > > > > > > > > device.
>
> > > > > > > > > > Jimmie
>
> > > > > > > > > My guess is paralleling the 4 helix antennas would have abroader
> > > > > > > > > bandwidth than the impedance matched solution. Broadband is good in
> > > > > > > > > the sense that it allows for more error in the construction.- Hide quoted text -
>
> > > > > > > > > - Show quoted text -
>
> > > > > > > > Usually paralelling(stacking) antennas means a narrower bandwidth.
> > > > > > > > This statement assumes all the stacked antennas are identical.
>
> > > > > > > > Jimmie
>
> > > > > > > I see no reason for stacked antennas to have a narrower bandwidth. Can
> > > > > > > you elaborate?- Hide quoted text -
>
> > > > > > > - Show quoted text -
>
> > > > > > Sorry I was thinking of bandwidth in terms of frequency versus VSWR.
> > > > > > This is usally the limiting factor as gain bandwidth is almost always
> > > > > > much broader
> > > > > > than VSWR bandwidth.
> > > > > > As of yet I dont know whether this will be a serious consequence or
> > > > > > not *concerning the helix antenna.
>
> > > > > > My plan is to build the antenna and tune it for greatest field
> > > > > > strength
>
> > > > > > A few years ago I stacked 2 2 meter 6 element quad antennas. I had
> > > > > > plans to stack 4 but didnt do it because
> > > > > > of the VSWR excursion from one end of the band to the other.
> > > > > > My solidstate amp was not fond of the 2 to 1 VSWR near the bandedges.
>
> > > > > > In this situation the VSWR bandwidth of 2 antennas was less than 1
> > > > > > antenna and with 4 antennas it was even less.
> > > > > > I am sure the array would have still exhibited considerable gain if I
> > > > > > had a way to readily correct for the impedance changes seen by my
> > > > > > amplifier.
>
> > > > > > Jimmie
>
> > > > > I wonder if the VSWR effects were due to coupling between antennas?- Hide quoted text -
>
> > > > > - Show quoted text -
>
> > > > I dont know, the antennas came with printouts from NEC antenna
> > > > modeling software. One of the parameters given was a diagram of their
> > > > capture area. The antennas were place according to this data with
> > > > their capture areas just touching. A local ham who is very much into
> > > > antenna modeling verified the data that came with the antennas. At the
> > > > time I was surprised by the reccomenced spacing thinking it was
> > > > excessive until I discovered that rules saying 1/2 or 5/8 spacing was
> > > > not always correct.- Hide quoted text -
>
> > > > - Show quoted text -
>
> > > Source of info on stacking antennashttp://www.ifwtech.co.uk/g3sek/stacking/stacking2.htm.
>
> > > Ian is extremely knowledgable on the *subject.
>
> > > Jimmie
>
> > I could see the stacked yagis interacting. The problem with beam
> > antennas is from the top and bottom, they more or less look like
> > dipoles because the driven element is not shielded from those
> > directions. I never stacked any beams, but if I did, I'd consider
> > antenna designs that had what amounts to a corner reflector at the
> > back of each antenna. That would shield the driven element.
>
> > I've been trying to DF vertically polarized UHF signals with a yagi. I
> > find it really hard to find a peak and suspect there is just too much
> > gain from the dipole as view from top and bottom. I've DFed HF with
> > loop using the null, and that works very well. The particular UHF
> > signal is heavily modulated, so the cheap double ducky box doesn't
> > work.- Hide quoted text -
>
> > - Show quoted text -
>
> I use a "Little L-per" direction finder and sometimes use a Yagi with
> a little handheld VHF UHF radio. When I use the YAGI sometimes I turn
> it around backwards and search for the null instead of the peak. Also
> you need to check the pattern of your yagi. Some can be rather skewed
> from what you think they should be.
>
> Jimmie
I've tried the backward yagi. The trouble is you get a lot of
reflection. One oddball scheme I have used with control channels, ie.
digital signals, is to view the eye pattern via software demodulation.
The widest open eye corresponds to the cleanest and thus most direct
signal. I've also done the "remove the antenna" trick once you get
close.
The L-per is a bit expensive for hobby use unless there are DIY
scheme.
On Aug 8, 10:40*pm, m...@sushi.com wrote:
> On Aug 8, 1:20*pm, jimmi...@gmail.com wrote:
>
>
>
>
>
> > On Aug 8, 3:56*am, m...@sushi.com wrote:
>
> > > On Aug 7, 1:23*pm, jimmi...@gmail.com wrote:
>
> > > > On Aug 7, 4:16*pm, jimmi...@gmail.com wrote:
>
> > > > > On Aug 3, 11:49*pm, m...@sushi.com wrote:
>
> > > > > > On Aug 2, 8:58*pm, jimmi...@gmail.com wrote:
>
> > > > > > > On Aug 2, 2:18*am, m...@sushi.com wrote:
>
> > > > > > > > On Aug 1, 1:33*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > > On Jul 31, 1:12*am, m...@sushi.com wrote:
>
> > > > > > > > > > On Jul 30, 1:57*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > > > > On Jul 29, 11:47*pm, m...@sushi.com wrote:
>
> > > > > > > > > > > > On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > > > > > > In WiFi is there any standard convention for the polarity of a helical
> > > > > > > > > > > > > antenna. I am building a 40 turn unit and wanted to know whether I
> > > > > > > > > > > > > should build it right or left handed.
>
> > > > > > > > > > > > > Yes I know this will only matter when trying to connect with other
> > > > > > > > > > > > > systems that use circular polarity.
>
> > > > > > > > > > > > > Jimmie
>
> > > > > > > > > > > > Please post how it works out. Also, have you considered building a 4
> > > > > > > > > > > > 10 turn helix (heli?) and run in parallel. That gets around the
> > > > > > > > > > > > matching issue.
>
> > > > > > > > > > > Yes, I thought about that but I have plans for the 40turn unit
> > > > > > > > > > > including the matching device. Also I have access to a Network
> > > > > > > > > > > Analyzer and S pararamter test set for tuning it up. I think building
> > > > > > > > > > > the matching network may be easier than build a phasing harness for 4
> > > > > > > > > > > Helix antennas. However I have never done this beforeso plans may
> > > > > > > > > > > change. Who knows, if things work out OK I may build a 4 X 40 turn
> > > > > > > > > > > device.
>
> > > > > > > > > > > Jimmie
>
> > > > > > > > > > My guess is paralleling the 4 helix antennas would havea broader
> > > > > > > > > > bandwidth than the impedance matched solution. Broadband is good in
> > > > > > > > > > the sense that it allows for more error in the construction.- Hide quoted text -
>
> > > > > > > > > > - Show quoted text -
>
> > > > > > > > > Usually paralelling(stacking) antennas means a narrower bandwidth.
> > > > > > > > > This statement assumes all the stacked antennas are identical.
>
> > > > > > > > > Jimmie
>
> > > > > > > > I see no reason for stacked antennas to have a narrower bandwidth. Can
> > > > > > > > you elaborate?- Hide quoted text -
>
> > > > > > > > - Show quoted text -
>
> > > > > > > Sorry I was thinking of bandwidth in terms of frequency versus VSWR.
> > > > > > > This is usally the limiting factor as gain bandwidth is almost always
> > > > > > > much broader
> > > > > > > than VSWR bandwidth.
> > > > > > > As of yet I dont know whether this will be a serious consequence or
> > > > > > > not *concerning the helix antenna.
>
> > > > > > > My plan is to build the antenna and tune it for greatest field
> > > > > > > strength
>
> > > > > > > A few years ago I stacked 2 2 meter 6 element quad antennas. I had
> > > > > > > plans to stack 4 but didnt do it because
> > > > > > > of the VSWR excursion from one end of the band to the other.
> > > > > > > My solidstate amp was not fond of the 2 to 1 VSWR near the band edges.
>
> > > > > > > In this situation the VSWR bandwidth of 2 antennas was less than 1
> > > > > > > antenna and with 4 antennas it was even less.
> > > > > > > I am sure the array would have still exhibited considerable gain if I
> > > > > > > had a way to readily correct for the impedance changes seen by my
> > > > > > > amplifier.
>
> > > > > > > Jimmie
>
> > > > > > I wonder if the VSWR effects were due to coupling between antennas?- Hide quoted text -
>
> > > > > > - Show quoted text -
>
> > > > > I dont know, the antennas came with printouts from NEC antenna
> > > > > modeling software. One of the parameters given was a diagram of their
> > > > > capture area. The antennas were place according to this data with
> > > > > their capture areas just touching. A local ham who is very much into
> > > > > antenna modeling verified the data that came with the antennas. At the
> > > > > time I was surprised by the reccomenced spacing thinking it was
> > > > > excessive until I discovered that rules saying 1/2 or 5/8 spacingwas
> > > > > not always correct.- Hide quoted text -
>
> > > > > - Show quoted text -
>
> > > > Source of info on stacking antennashttp://www.ifwtech.co.uk/g3sek/stacking/stacking2.htm.
>
> > > > Ian is extremely knowledgable on the *subject.
>
> > > > Jimmie
>
> > > I could see the stacked yagis interacting. The problem with beam
> > > antennas is from the top and bottom, they more or less look like
> > > dipoles because the driven element is not shielded from those
> > > directions. I never stacked any beams, but if I did, I'd consider
> > > antenna designs that had what amounts to a corner reflector at the
> > > back of each antenna. That would shield the driven element.
>
> > > I've been trying to DF vertically polarized UHF signals with a yagi. I
> > > find it really hard to find a peak and suspect there is just too much
> > > gain from the dipole as view from top and bottom. I've DFed HF with
> > > loop using the null, and that works very well. The particular UHF
> > > signal is heavily modulated, so the cheap double ducky box doesn't
> > > work.- Hide quoted text -
>
> > > - Show quoted text -
>
> > I use a "Little L-per" direction finder and sometimes use a Yagi with
> > a little handheld VHF UHF radio. When I use the YAGI sometimes I turn
> > it around backwards and search for the null instead of the peak. Also
> > you need to check the pattern of your yagi. Some can be rather skewed
> > from what you think they should be.
>
> > Jimmie
>
> I've tried the backward yagi. The trouble is you get a lot of
> reflection. One oddball scheme I have used with control channels, ie.
> digital signals, is to view the eye pattern via software demodulation.
> The widest open eye corresponds to the cleanest and thus most direct
> signal. I've also done the "remove the antenna" trick once you get
> close.
>
> The L-per is a bit expensive for hobby use unless there are DIY
> scheme.- Hide quoted text -
>
> - Show quoted text -
A variable attenuator in line with the Yagi will help a lot with
reflections.
I have one of those binary switch selected attenuators. I think it can
switch in 3-20 db pads a 10, a 5, a 3 . If you can monitor the AGC
voltage on the rx with a voltmeter this give a much better indication
of the strongest signal than an S meter.
I work at an airport an people used to think I was nuts but when I
used to look for Emergency Locator Transmitters I would start by
climping the Control Tower. By getting up high I didnt have as much
problems with reflections and could often point directly at the
offending aircraft from the catwalk of the tower.
On Aug 9, 4:48*pm, jimmi...@gmail.com wrote:
> On Aug 8, 10:40*pm, m...@sushi.com wrote:
>
>
>
> > On Aug 8, 1:20*pm, jimmi...@gmail.com wrote:
>
> > > On Aug 8, 3:56*am, m...@sushi.com wrote:
>
> > > > On Aug 7, 1:23*pm, jimmi...@gmail.com wrote:
>
> > > > > On Aug 7, 4:16*pm, jimmi...@gmail.com wrote:
>
> > > > > > On Aug 3, 11:49*pm, m...@sushi.com wrote:
>
> > > > > > > On Aug 2, 8:58*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > On Aug 2, 2:18*am, m...@sushi.com wrote:
>
> > > > > > > > > On Aug 1, 1:33*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > > > On Jul 31, 1:12*am, m...@sushi.com wrote:
>
> > > > > > > > > > > On Jul 30, 1:57*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > > > > > On Jul 29, 11:47*pm, m...@sushi.com wrote:
>
> > > > > > > > > > > > > On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > > > > > > > > > > > > > In WiFi is there any standard convention for the polarity of a helical
> > > > > > > > > > > > > > antenna. I am building a 40 turn unit and wanted to know whether I
> > > > > > > > > > > > > > should build it right or left handed.
>
> > > > > > > > > > > > > > Yes I know this will only matter when trying toconnect with other
> > > > > > > > > > > > > > systems that use circular polarity.
>
> > > > > > > > > > > > > > Jimmie
>
> > > > > > > > > > > > > Please post how it works out. Also, have you considered building a 4
> > > > > > > > > > > > > 10 turn helix (heli?) and run in parallel. That gets around the
> > > > > > > > > > > > > matching issue.
>
> > > > > > > > > > > > Yes, I thought about that but I have plans for the 40 turn unit
> > > > > > > > > > > > including the matching device. Also I have access to a Network
> > > > > > > > > > > > Analyzer and S pararamter test set for tuning it up.. I think building
> > > > > > > > > > > > the matching network may be easier than build a phasing harness for 4
> > > > > > > > > > > > Helix antennas. However I have never done this before so plans may
> > > > > > > > > > > > change. Who knows, if things work out OK I may build a 4 X 40 turn
> > > > > > > > > > > > device.
>
> > > > > > > > > > > > Jimmie
>
> > > > > > > > > > > My guess is paralleling the 4 helix antennas would have a broader
> > > > > > > > > > > bandwidth than the impedance matched solution. Broadband is good in
> > > > > > > > > > > the sense that it allows for more error in the construction.- Hide quoted text -
>
> > > > > > > > > > > - Show quoted text -
>
> > > > > > > > > > Usually paralelling(stacking) antennas means a narrowerbandwidth.
> > > > > > > > > > This statement assumes all the stacked antennas are identical.
>
> > > > > > > > > > Jimmie
>
> > > > > > > > > I see no reason for stacked antennas to have a narrower bandwidth. Can
> > > > > > > > > you elaborate?- Hide quoted text -
>
> > > > > > > > > - Show quoted text -
>
> > > > > > > > Sorry I was thinking of bandwidth in terms of frequency versus VSWR.
> > > > > > > > This is usally the limiting factor as gain bandwidth is almost always
> > > > > > > > much broader
> > > > > > > > than VSWR bandwidth.
> > > > > > > > As of yet I dont know whether this will be a serious consequence or
> > > > > > > > not *concerning the helix antenna.
>
> > > > > > > > My plan is to build the antenna and tune it for greatest field
> > > > > > > > strength
>
> > > > > > > > A few years ago I stacked 2 2 meter 6 element quad antennas.. I had
> > > > > > > > plans to stack 4 but didnt do it because
> > > > > > > > of the VSWR excursion from one end of the band to the other..
> > > > > > > > My solidstate amp was not fond of the 2 to 1 VSWR near the band edges.
>
> > > > > > > > In this situation the VSWR bandwidth of 2 antennas was lessthan 1
> > > > > > > > antenna and with 4 antennas it was even less.
> > > > > > > > I am sure the array would have still exhibited considerablegain if I
> > > > > > > > had a way to readily correct for the impedance changes seenby my
> > > > > > > > amplifier.
>
> > > > > > > > Jimmie
>
> > > > > > > I wonder if the VSWR effects were due to coupling between antennas?- Hide quoted text -
>
> > > > > > > - Show quoted text -
>
> > > > > > I dont know, the antennas came with printouts from NEC antenna
> > > > > > modeling software. One of the parameters given was a diagram oftheir
> > > > > > capture area. The antennas were place according to this data with
> > > > > > their capture areas just touching. A local ham who is very muchinto
> > > > > > antenna modeling verified the data that came with the antennas.At the
> > > > > > time I was surprised by the reccomenced spacing thinking it was
> > > > > > excessive until I discovered that rules saying 1/2 or 5/8 spacing was
> > > > > > not always correct.- Hide quoted text -
>
> > > > > > - Show quoted text -
>
> > > > > Source of info on stacking antennashttp://www.ifwtech.co.uk/g3sek/stacking/stacking2.htm.
>
> > > > > Ian is extremely knowledgable on the *subject.
>
> > > > > Jimmie
>
> > > > I could see the stacked yagis interacting. The problem with beam
> > > > antennas is from the top and bottom, they more or less look like
> > > > dipoles because the driven element is not shielded from those
> > > > directions. I never stacked any beams, but if I did, I'd consider
> > > > antenna designs that had what amounts to a corner reflector at the
> > > > back of each antenna. That would shield the driven element.
>
> > > > I've been trying to DF vertically polarized UHF signals with a yagi.. I
> > > > find it really hard to find a peak and suspect there is just too much
> > > > gain from the dipole as view from top and bottom. I've DFed HF with
> > > > loop using the null, and that works very well. The particular UHF
> > > > signal is heavily modulated, so the cheap double ducky box doesn't
> > > > work.- Hide quoted text -
>
> > > > - Show quoted text -
>
> > > I use a "Little L-per" direction finder and sometimes use a Yagi with
> > > a little handheld VHF UHF radio. When I use the YAGI sometimes I turn
> > > it around backwards and search for the null instead of the peak. Also
> > > you need to check the pattern of your yagi. Some can be rather skewed
> > > from what you think they should be.
>
> > > Jimmie
>
> > I've tried the backward yagi. The trouble is you get a lot of
> > reflection. One oddball scheme I have used with control channels, ie.
> > digital signals, is to view the eye pattern via software demodulation.
> > The widest open eye corresponds to the cleanest and thus most direct
> > signal. I've also done the "remove the antenna" trick once you get
> > close.
>
> > The L-per is a bit expensive for hobby use unless there are DIY
> > scheme.- Hide quoted text -
>
> > - Show quoted text -
>
> A variable attenuator in line with the Yagi will help a lot with
> reflections.
>
> I have one of those binary switch selected attenuators. I think it can
> switch in 3-20 db pads a 10, a 5, a 3 . If you can monitor the AGC
> voltage on the rx with a voltmeter this give a much better indication
> of the strongest signal than an S meter.
>
> I work at an airport an people used to think I was nuts but when I
> used to look for Emergency Locator Transmitters I would start by
> climping the Control Tower. By getting up high I didnt have as much
> problems with reflections and could often point directly at the
> offending aircraft from the catwalk of the tower.
>
> Jimmie
I have a HP RF attenuator. I forgot to bring it with me when I was
DFing these repeater sites, but will do so this time. I used a
Minicircuits 4 way splitter as an adhoc attenuator, but it wasn't
enough.
On Aug 2, 2:28*am, m...@sushi.com wrote:
> On Aug 1, 5:09*pm, jimmi...@gmail.com wrote:
>
>
>
>
>
> > On Aug 1, 4:33*pm, jimmi...@gmail.com wrote:
>
> > > On Jul 31, 1:12*am, m...@sushi.com wrote:
>
> > > > On Jul 30, 1:57*pm, jimmi...@gmail.com wrote:
>
> > > > > On Jul 29, 11:47*pm, m...@sushi.com wrote:
>
> > > > > > On Jul 29, 1:52*pm, jimmi...@gmail.com wrote:
>
> > > > > > > In WiFi is there any standard convention for the polarity of a helical
> > > > > > > antenna. I am building a 40 turn unit and wanted to know whether I
> > > > > > > should build it right or left handed.
>
> > > > > > > Yes I know this will only matter when trying to connect with other
> > > > > > > systems that use circular polarity.
>
> > > > > > > Jimmie
>
> > > > > > Please post how it works out. Also, have you considered building a 4
> > > > > > 10 turn helix (heli?) and run in parallel. That gets around the
> > > > > > matching issue.
>
> > > > > Yes, I thought about that but I have plans for the 40 turn unit
> > > > > including the matching device. Also I have access to a Network
> > > > > Analyzer and S pararamter test set for tuning it up. I think building
> > > > > the matching network may be easier than build a phasing harness for 4
> > > > > Helix antennas. However I have never done this before so plans may
> > > > > change. Who knows, if things work out OK I may build a 4 X 40 turn
> > > > > device.
>
> > > > > Jimmie
>
> > > > My guess is paralleling the 4 helix antennas would have a broader
> > > > bandwidth than the impedance matched solution. Broadband is good in
> > > > the sense that it allows for more error in the construction.- Hide quoted text -
>
> > > > - Show quoted text -
>
> > > Usually paralelling(stacking) antennas means a narrower bandwidth.
> > > This statement assumes all the stacked antennas are identical.
>
> > > Jimmie- Hide quoted text -
>
> > > - Show quoted text -
>
> > This should be of interest to anyo one wanting to build a helix
> > antena.
>
> >http://www.qsl.net/ve3cvg/antennas/2400/
>
> > Jimmie
>
> When I build antennas, I try to use all copper if I can. Otherwise,
> you get a battery connecting Al to copper. I'm not sure about
> connecting copper to galvanized. I've built a few log periodics (VHF/
> UHF) and used that gunk (OK, not a technical term) used with Al
> wiring. Still, it deteriorates with time. *Consider using copper wire.
>
> Have you considered the biquad? Unless you have circular polarization
> on both ends, you will lose 3db when interfacing with linear polarized
> antennas, so 16db becomes 13db, which is close to the biquad.
>
> I guess a long helix would be better for snooping purposes since not
> everyone is vertically polarized.- Hide quoted text -
>
> - Show quoted text -
I found the helix not to be such a good antenna for point to point in
this case.
The final design was a 10 element Quagi( quad driven element and
reflector
with yagi directors). The Quagi has the advantage of being polarity
selective.
The antennas were mounted for horizontal polarity thus rejecting much
of the
mostly vertically polarized interference.
I also discovered that on the WRT54s that the antenna ports can be
operated
with one port as transmit and the other receive at least if you are
running
DD WRT software .
Helix antenna 
Linear Mode
