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Horizontal FM

Something I have mentioned before is the lack of use of horizontal FM.
A mode I used years ago as a B class and worked very well over long distances.
I have worked SOTA activators on some occasions when conditions have been favourable with vertical polarization from Devon to the Penines.
To-day Richard G0IBE/P was activating WB005 and although I heard him and called to which he responded both using vertical polarization we were not able to complete.
He then changed to horizontal polarization as did I.
The exchange of reports were then up to 59+ both ways.
Only a single element dipole is required, for real DX on your HH why not try a 3 element sota beam horizontally on FM. 73 Don.

In reply to G0RQL:
Hi Don,
You are wasting your time, nobody takes any notice, I also was preaching horizontal FM when SOTA started to no avail!
One example was a station on a medium height NW summit using a 290R, 2.5W with the infamous ‘rubber duck’ went from nothing to a workable 4 x 1 by laying over the radio and lining it up square on to my location.
Well done with Richard.
Regards from the other Don.
G0NES

In reply to G0RQL:

That is okay if you tell people. By people I mean me of course so I can switch polarity on my cross Yagi. Ditto if you only have a vertical and you are on SSB. It is no problem if we know but the losses from cross polarity could mean I am beaming straight at you but hear nothing. Personally I prefer if everyone sticks to the conventional polarity then I know which radio to listen on.

Steve GW7AAV

In reply to G0RQL:

Something I have mentioned before is the lack of use of horizontal FM.
A mode I used years ago as a B class and worked very well over long
distances.

I’ve been preaching the Gospel acording to Saint Collinear for over a year now, Don. We worked on the 8th Feb from G/SP-004 a distance of over 190 miles and there was no VHF lift that day. OK, they are a bit of a PITA to carry and put together, however, the pay-back is well worth the effort. There are collinears out there with 9.3dB of gain, which is into beam territory. Ok, once again not ideal for poratable use, neither is the Antron-99, but the results speak for themselves.

In reply to G0RQL:
I worked Richard today 2m Horizontal FM on WB-005 and it was the only way i would of worked him. So well done Richard for doing it.

Regards Nigel 2e0nhm

In reply to 2E0YYY:

worth the effort. There are collinears out there with 9.3dB of gain,
which is into beam territory.

But in what kind of pattern? I’m always a bit suspicious of the gain figures for essentially omni-directional antennas. How about homebrewing a coaxial colinear - it’d roll up for easy transportation and rigging.

As regards the HFM, I just a a reliable chat with Don G0RQL for 15 minutes using HFM - approx 120 miles with the Brecon beacons in the way, seems pretty good to me. Surely if an activator noted HFM in their alert then people would flick over the coax switch?

73 de Dave M0MYA (on Geoff’s computer).

In reply to 2E0BTR:
Not much of an expert here, but was wondering does Horizontal Polarity actually travel further? If you had 2 beams that were exactly the same, if one was vertical and one was horizontal which one would go further? Or if so, does it make a significant difference?

As I mentioned is a post elsewhere, why use FM at all?? SSB has got to be the way forward! Beams and more efficiency, it really is a no brainer!

73

Matt G8XYJ

In reply to 2E0BTR:

But in what kind of pattern? I’m always a bit suspicious of the gain
figures for essentially omni-directional antennas. How about
homebrewing a coaxial colinear - it’d roll up for easy transportation
and rigging.

With a collinear /P, I think it’s a case of suck it and see, Dave. You’ll either love it or hate it. I’ve dragged all sorts of 2m antennas up Shining Tor, even a ZL special. Got fed up with that after about half an hour and sold it at the very next rally I attended :frowning:

Andy MM0FMF showed me his home brew roll up antenna which weighed nothing, IIRC. That seemed to have a good gain figure.

As regards the HFM, I just a a reliable chat with Don G0RQL for 15
minutes using HFM - approx 120 miles with the Brecon beacons in the
way, seems pretty good to me. Surely if an activator noted HFM in
their alert then people would flick over the coax switch?

Good point, Dave.

73 Mike
2E0YYY

In reply to G8XYJ:

but was wondering does Horizontal Polarity actually travel further?

Experimental results show that horizontal VHF/UHF polarisation has a noticeable and worthwhile advantage over vertical polarisation.

why use FM at all?

Because the radio you have with you doesn’t have SSB.

Andy
MM0FMF

In reply to MM0FMF:

Because the radio you have with you doesn’t have SSB.

Andy
MM0FMF

Their is the underlying issue, but if you use an 817 then it makes perfect sense!!

Halo on the car I think!!

Mike - You should seriously consider a Slim Jim made out of Ladder feed, Omni Directional and very cheap and easy to make!

73

Matt G8XYJ

In reply to G8XYJ:

Not much of an expert here, but was wondering does Horizontal Polarity
actually travel further?

I recall Brian G8ADD et al discussing this matter when SOTA was in its infancy. There were some very interesting reasons put forward as to why horizontal polarisation beats vertical. The one that stood out is that a lot of QRM is vertically polarised. I’m sure someone here can give us more details.

As I mentioned is a post elsewhere, why use FM at all??

For some I think it’s probably for the same reasons you run 4m FM and 23cm FM on the hill - the kit just isn’t available to the activator to do any other mode. I recall with great fondness my first few activations using a handheld and 2m slimjim (because it’s all I could afford), some of the most fun I’ve had with radios on hills. Now, if only it had been enhanced with a lovely bit of horizontal polarisation, my eyes would be popping out of my head as I looked at the long list on GM’s in the log, hi! I do miss the VHF FM days - perhaps you and I can have a role reversal on one of those HEMs sometime? :slight_smile:

73,
Dave M0MYA.

In reply to M0MYA:

Well, I’ve started using vertical polarisation on SSB. As I change over from SSB to FM I flip the beam over on its side and before I have moved over to FM, I’ve put out some calls on SSB. So far no real results, but I did change to vertical on Grange Fell GM/SS-249 in order to work Mike G4BLH on CW. Not all fixed stations can get a beam up and many exist with a simple vertical.

I’m considering putting a 45 degree clamp on the beam to try slant polarisation… but which way, left or right? I seem to recall that at least one chaser has a slant polarised 2m antenna, so I’d better get it right. :slight_smile:

Gerald G4OIG

In reply to M0MYA:
I do miss the VHF FM days - perhaps you and I can have a role reversal on one of those HEMs sometime? :slight_smile:

Always happy for you to have 4m FM mate! OK on your sentiments about budgeting for radios, I must admit that I am in a lucky position to own the 817, but it is somewhat annoying knowing that you could make the LD from where we live on 2m SSB but we both know on FM we dont stand half a chance! However as long as people are on the hills playing on the radio then who minds?

A more sombre G8XYJ

In reply to thread:

As I understand it horizontal polarisation in any mode travels further because it diffracts over edges such as ridges more readily. Horizontal FM would be a good mode if only one could persuade the chasers to adopt it, but most FM users are set up for local and repeater use and would probably not see much benefit in changing!

Colinears achieve omnidirectional gain by compressing the main lobe down towards the horizon, but this implies the need to keep them accurately vertical so that the gain is the same in all directions. Tilt them and you will get less gain in the direction of tilt and its opposite. I remember putting a Moonraker three band colinear on a flexible mast once, the QSB in a high wind was all too obvious!

73

Brian G8ADD

In reply to G8ADD:

Circular polarization anybody?

Sorry, I’ll get my coat :wink:

Seriously though, Horizontal polarization does have advantages over vertical in certain situations. Vertical VHF FM works well if the station you are working may be moving around & you have a fixed antenna, typical of the most common use of VHF by Taxi companies & the like.

Most amateurs do indeed have vertically polarized VHF FM antennas for this reason. It works fine for it’s purpose.

As Radio Amateurs, we can experiment, which taxi companies & the like cannot.

I am sure that the radiation pattern for a simple dipole at the typical height above ground we use when modeled in horizontal & vertical polarization would exhibit a more directional pattern when horizontal, due to the ground maybe :wink:

Certainly the natural noise level will be lower, as most, if not all natural noise is vertically polarized (At least the Electrical component is). Think of a Thunderstorm, or be caught in one & you get the idea…

Man made sources of noise are a different kettle of fish, & you should be as far away from them as possible in oder to enjoy good reception on your radio telegraphy apparatus.

Vertical Co-linear antennas do not work very well at the bottom of valleys.

I may well fire some 2m HFM towards Devon the next time I am out on a Hill :wink:

Best 73,

Mark G0VOF

The adoption of horizontal polarisation for DX working was, in part, based on the result of experiments by Ed Tilton W1HDQ back in the 1940s and 50s. He did extensive tests that seemed to show that horizontal polarisation was more effective on VHF at extended ranges.

Vertical polarisation was adopted for FM because it is far easier to implement aerials suitable for use by mobiles and handportables.

73

Richard
G3CWI

In reply to G8XYJ:

The reason for horizontal polarisation at VHF being better than vertical is simply one of directivity (and therefore perceived “gain”) in azimuth rather than directivity in elevation - ignoring other inconvenient facts like reflections!!

The use of vertical polarisation as a, de facto, standard came about for two reasons, it is easier to fix a vertical antenna to a vehicle and vehicles tend to work in built-up areas with multiple reflections from buildings. Azimuthal directivity would, at best, be inconvenient in this case.

Unfortunately most base stations equipped for VHF FM use a vertically polarised antenna and the cross polarisation loss between horizontal and vertical outweighs other considerations. However, for best VHF DX always use horizontal in preference to vertical polarisation at both ends and take advantage of the small element of directional gain.

If running HF forget all this, there are completely different arguments in play!!

73

Barry GM4TOE

In reply to G3CWI:

based on the result of experiments by Ed Tilton W1HDQ back in the
1940s and 50s.

Part of his results were explained by people suggesting that there are lots of vertical metal objects which tend to absorb vertically polarised radiation more than they absorb horizontaly polarised radiation.

Horizontal if you want DX, vertical if you want higher QSO numbers. Both if you want both. Simples.

To fully enjoy the benefits of horizontal and SSB, then between 8pm and 10.30pm on the first Tuesday of the month is the time to do it. These events are even better supported than the major weekend VHF contests these days.

Night is also good for FM contacts on vertical. There’s always plenty of people retreated to their shacks and monitoring the 2m FM frequencies after tea-time, and right through to midnight.

Tom M1EYP

In reply to G4OIG:

The other consideration is the effect on polarisation when the signal is reflected, something that happens a lot in these parts. I remember working a station over in the East of the Lake District (it may have been you Gerald) who was running SSB Horizontal & I was Vertical (since that is all I have for 2m) and got a good copy but when they switched over to Vertical the signal strength dropped significantly. So if you have the time and inclination (pardon the pun) it may be worth trying the opposite polatity for those marginal contacts whether you are using SSB or FM (or even CW).

73,
Colin