A bit of off-topic advice requested - horizontal polarization with repeaters?

[KD6RF]

I read this group with interest, and like the attention to technical detail I find.

 

Although a bit off-topic, I thought I would ask my question here.

 

I like simplicity, and have a grand total of 3 antennas, 160-60M short vertical (nearing completion), 60-6M short vertical ( http://www.eham.net/articles/29052 ), and a 220-4.5GHz Vivaldi variation of my design soon to be on the market. The last bit of pectrum to fill in is the 2 meter antenna, to be used primarily for WSPR and satellite.

 

Q – do you find horizontal polarization to be adequate for FM repeater work, especially in regard to distant non-LOS over-the-hills repeaters?

 

Like I said, I like things simple, and would prefer to stay with pure horizontal polarization.  However, if there is a too big a performance hit for nominally vertically polarized links, I may have to go with something else, perhaps tilting at 45 degrees?

 

[Glenn Elmore]

I'll be interested to see your broadband VHF-uW antenna when details are available. As you know, we recently published a very broadband design (160m - 3 cm) and we're always interested to see other approaches.

I don't know that I can answer your question fully. So much depends upon what you mean by 'adequate' and non-LOS.� So far on 2m, we have seen quite a few completely different propagation mechanisms and I've learned something about both 'known' ones and new ones.
For non-LOS operation demanding +10 sorts of S/N (FM quieting) considerable ERP may be required. Also there's a difference if you only want it occasionally and can put up with intermittant paths (tropo, ACS ...) or you want to guarantee near-100% availability.
One of the surprising things to me was the degree of polarization preservation we see over very indirect, non-LOS paths when the mechanism isn't ACS and not-too-much tropo. WSPR has allowed comparisons of polarization over the N6GN-KP4MD path across two healthy mountain ranges and revealed a great deal of polarization preservation. That is not true for ACS mechanisms but whatever "scatter" or "knife-edge" is really, it's not something that scrambles polarization as I would have previously thought.

I haven't tried to bring up DX repeaters much lately with the WSPR station. My intuition and distant history experience tells me that there may well be 10 dB crosspolarization penalty for many situations.� This could be a deal breaker if you are at marginal link levels.� Antenna height is an extremely important factor, maybe more so than antenna polarization, for many paths. I would say a 4X height increase probably easily trumps crosspol penalty on virtually any of the paths and mechanisms we've seen so far.

Maybe others will have some experiences to share in this regard.

Glenn n6gn

On 09/29/2013 01:43 PM, KD6RF wrote:

I read this group with interest, and like the attention to technical detail I find.

�

Although a bit off-topic, I thought I would ask my question here.

�

I like simplicity, and have a grand total of 3 antennas, 160-60M short vertical (nearing completion), 60-6M short vertical ( http://www.eham.net/articles/29052 ), and a 220-4.5GHz Vivaldi variation of my design soon to be on the market. The last bit of pectrum to fill in is the 2 meter antenna, to be used primarily for WSPR and satellite.

�

Q � do you find horizontal polarization to be adequate for FM repeater work, especially in regard to distant non-LOS over-the-hills repeaters?

�

Like I said, I like things simple, and would prefer to stay with pure horizontal polarization. �However, if there is a too big a performance hit for nominally vertically polarized links, I may have to go with something else, perhaps tilting at 45 degrees?

�

--
You received this message because you are subscribed to the Google Groups "2 Meter WSPR" group.
To unsubscribe from this group and stop receiving emails from it, send an email to 2-meter-wspr...@googlegroups.com.
To post to this group, send email to 2-mete...@googlegroups.com.
Visit this group at http://groups.google.com/group/2-meter-wspr.
For more options, visit https://groups.google.com/groups/opt_out.

[Leigh Rainbird]

From experience here, I would suggest that you would need a vertical and horizontal antenna (or perhaps a yagi that has both horizontal and vertical elements). I've seen at least 20dB attenuation from trying to run horizontal to repeaters, I can barely get local repeaters that are usually full scale on vertical.
 
Leigh VK2KRR
 

---

Date: Sun, 29 Sep 2013 13:43:22 -0700
From: benz...@mindspring.com
To: 2-mete...@googlegroups.com
Subject: {2 Meter WSPR} A bit of off-topic advice requested - horizontal polarization with repeaters?

[Scott Avery WA6LIE]

Leigh,

 

You are correct on the 20db vertical vs horizontal.

In reality, you need both especially on long haul refracted stuff.

That is why I use a Delta Loop fed at the bottom V.

Fed at that point, the antenna is horizontal and vertically polarized.

You can feed to make vertical or horizontal, or even change the loop orientation.

 

Add a reflector for a bit of gain in your favorite direction.

 

73, Scott WA6LIE

Salinas, CA.

[Line Printer]

Greetings!!

Sometime this evening, my power supply decided a lonche break was called
for and left me running from a battery. Deciding the power meter looked
low, it caused me to notice my power supply not being lit up.

The symptoms are as Astron with meters being dark and toggling the on/off
switch made no difference. I've put in an Astron power supply with no
meters. ^-^

Thank you for your patience!

73s,
Kevin Martinez
KI6STW


--
------------------------------------------------------------------------
Line Printer System | HODIE NATUS EST RADICI FRATER
lps at rahul 'dot' net | 645/6180 BOS/BCE
------------------------------------------------------------------------

[KD6RF]

Thanks for the replies.

 

As a result, I threw a 4 el yagi into EZNec, and fooled around with various tilts and rotations.

 

What I already knew, is that simply pointing up a horiz polarized yagi by 30 degs or so gets rid of the deep elevation nulls one sees when working satellites.  We lose about 2 dB at the first lobe (about 5 degs elevation), but the severe 20 or 30 dB nulls as we go up in elevation drop way down to 2 to 5 dB nulls as the satellite rises.  Very workable.

 

Thanks Leigh, I started thinking about changing polarization around – I started with a yagi, rotated it 45 about it’s axis to give 45 deg polarization.  Then point up by 25 degs or so, and we end up with the nice null fill-ins for sat work, and retains most of the horizontal polarized low-angle lobe for WSPR and other terrestial weak signal work.  And still end up with 9 dB or so gain vertically polarized for repeater work (a few dB better than a ¼ wave vert at the same height).

 

So, the good news is that sat and repeaters are workable.  The mediocre news is that low angle horiz gain drops from 14 dB of so to around 11 dB for WSPR work.

 

Just might be good enough in a “Jack of all trades, master of none” sense :)

 

The multiple angles and rotations look a bit funky to my eye, but that’s life.  A corner fed quad  would look much better.

 

Anyway, thanks again all for the real-world info.  Can’t wait to get the Efratoms up and running and get some stable hardware on the air.

 

 

Glenn – kudos on the wideband antenna.  Decades ago, I recall how mysterious it was that a single conductor could be used as a transmission line.  It wasn’t until I went through the course work at UCB that it finally started making sense.  You have a very cool design. 

 

Not sure how to post pix here, but my Vivaldi design is something I discovered when working with another antenna design entirely that turned out to be muuuuch broader band than it should have been, and ended up finding the “easy-button” way of feeding and constructing a useful, low cost and marketable Vivaldi.  VSWR is below 1.6 or so from 220 MHz through 4 GHz, gain starts out around 7 dB and goes quickly up to 12 dB+ and is pretty flat out to 4 GHz. No matching networks or cavities normally associated with standard Vivaldi designs.  Am getting the mechanicals finished up so that I can start selling it.

 

[Glenn Elmore]

I used to use yagis at 45 degrees to accomplish  "dual mode" operation in that way.  Yes, there's a 3 dB penalty relative to perfect alignment but don't forget there is very likely already a penalty bigger than that for stations at the horizon because of far-field grounds.  I measured sun noise on a 35' high middlin' length yagi at 2m and found the peak at around 35 degrees!  I don't remember how far it was down from that at the horizon but I think beyond my ability to measure at the time (1977).

You might be interested to note that the SWTL I describe is not the same as that described by Goubau and commonly taught in EM courses. Goubau's line was purportedly due to slowing of the wave by dielectric or surface roughening. In fact, I believe he was catagorically wrong. The line I use, a bare unfeatured conductor, is actually a TM mode that has been overlooked.  Heaviside's Telegrapher's Equation, commonly used to describe coaxial lines as well as many kinds of balanced lines, is in error (in a very profound way that I'll tell you about if you care to know) and does not predict the mode.  Stratton (Pres. Emer. MIT, 1041) Electromagnetic Theory finds theoretical basis for both TEM and TM modes in the general case of concentric cylinders (coax, fiber ... ) but dismisses it (also in error) in the practical case for coax. See the previous QEX article (also available as the 2nd article on http://www.sonic.net/~n6gn ) for some theoretical background and support if you are interested.

One of the problems we run into with VHF+ WSPR is that omni antennas, have smaller apertures and the "path loss" correspondingly increases with frequency. Of course there is no real loss on the path but a larger antenna that "catches" more signal is inherently directive. An electrically small antenna catches less. Thus, using yagis is a compromise for WPSR work.  My spots with KP4MD, for example, are not representative of the path because I am beaming 140 degrees to better catch KC6KGE.

K6PZB and I are playing with tri-band, 6,2,3/4 meter, designs that are still omni in azimuth but have more gain/aperture than dipoles or monopoles.

Best,

Glenn n6gn

[KD6RF]

Damn you Glenn!

I have enough on my plate in regard to projects that need to be finished up, and there you go, forcing me to read your articles so that I can understand the dielectric-less single conductor transmission line :)

[Glenn Elmore]

I let you off easy. :-)
The more complete article is at
http://www.corridorsystems.com/FullArticle.pdf
Glenn

[Line Printer]

Hello!

Sometime recently, my 2 meter amplifier has changed its job description to
resistor. It consumes power and radiates heat. Back in the "Good Ole
Daze", I had a power supply nicely optioned with meters displaying volts
output and current flowing. These days, I have a power supply optioned
with a flickering red power switch and a 60 Hz hummmmm.

As the new power supply has subtle ways, I hadn't noticed there was any
change in its operations or the equipment connected to it. The thing that
made me suspicious was the sound of the relay in the amplifier sounding
"softer" when the WSPR transmission began. The amplifier's LEDs look fine
but the power output check revealed that it was very similar to zero.

I'm now using the native IC-7000 radio with 10 watts and no amplifier.

With recent power events and Murphy-like events, my stack of equipment
needing repair is growing. ^-^

Patience is a Virtue!

[Steven Hess]

I still am printing you down here Line Printer at 10 watts..
Want me to drop power too and see what transpires?

Kevin you are running a halo antenna?

> --
> You received this message because you are subscribed to the Google Groups "2
> Meter WSPR" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to 2-meter-wspr...@googlegroups.com.
> To post to this group, send email to 2-mete...@googlegroups.com.
> Visit this group at http://groups.google.com/group/2-meter-wspr.
> For more options, visit https://groups.google.com/groups/opt_out.



--

____________
Apply appropriate technology. Use what works without prejudice.
Steven L Hess ARS KC6KGE DM05gd22
openSUSE Linux 12.3 KDE
Known as FlameBait and The Sock Puppet of Doom.

[Line Printer]

On Tue, 8 Oct 2013, Steven Hess wrote:

> I still am printing you down here Line Printer at 10 watts..
> Want me to drop power too and see what transpires?
>
> Kevin you are running a halo antenna?

Hi,

I've got a pair of M2 2 Meter HO Loops. The mast leans a little to the
north so perhaps there is slightly more gain to the south?

10 watts is almost 50 watts. ^-^

K