[VHFcontesting] horiz loops

[wa3tts at verizon.net]

>I think many try out the loop, don't
>hear anything because of its poor performance, and
>then give up on 2 meter SSB because there "is no
>activity."
>----------------------------
>It has been my experience that the typical new SSB >VHFer tries with their FM vertical and then gives up >for lack of both signals and DX.  A horizontal loop >would give 'em an extra couple of bels and a >significant amount of success.

I've run a three-band set of horiz loops for over 6 months now and find them a worthwhile addition to my current station, which is quite modest compared to what I ran 15-20 years ago. Then I had a killer hilltop and did not need a tower to work over 40 states on 2m and over 25 states on 1296. My current qth is about 50 feet in elevation off the west side of a hilltop, so I can hear and work stuff, but certainly not as well as the last qth where the elevation was 150 feet higher at ground level.
      Anyway, I had some yagis on my chimney around 30 ft up and wanted to have some omni antennas to listen around without wearing out the rotor. I also had 6,2 and 432 antennas on a single 6 foot mast and that was a lousy compromise.  I had to replace the rotor so decided to take down the 6M yagi and just run 2 and 432 yagis.
      I had a 3 inch steel vent pipe on the roof at the back of the house just off the apex, so I bolted a 1 inch pipe to it about 2 feet long and used that as a mount for two ten foot sections of HD radio shack mast. It's guyed at the 15 foot point where one 2M par loop resides and the second 2M Par loop resides at the top. Above that is one of those 4 stack 70cm Lowe's loop copper homebrews (July 2006 QST) on 3/4 inch copper waterpipe mast (5 feet tall bolted through the top of the RS mast) for 70cm. The 6 Meter loop is a few feet below the guy point.

     I went with this hoping that especially on 70cm, the extra 20 foot of elevation over the yagi would make a difference, especially to the east where the hill works as an RF absorber.  Well, the 4 loop stack on 70cm does get over the hilltop better than the yagi, by 3-4 s-units on tropo out to 150 mi or so. They are 6db down from the single 70cm yagi, but the omni rx feature does save on rotor wear. I basically listen on the loops all the time now and switch to a yagi once I determine the general direction where the other station is calling. With 50 watts and some enhancement, plus 350 mile contacts are possible.

      Twenty years ago we had vhf-uhf yagis that were good but still had side lobe "crud".  The latest computer modeled antennas put all the power where we want it and that is great. It's like a 3 db power improvement, but in many cases but we can't hear off the sides and back like 20 years B4. 

       I also noticed in a tropo duct event this fall the 70 cm loops were hearing beacons the single yagi was not. There are some high angle "flower pedal" lobes on the 4-loop stack and these manage to get into a duct at different angles than a horizon-mounted yagi. I wish I had my old az-el yagi setup as that would be ideal but the combination of separate omni loops and single yagis works out OK.  I think it was well worth the $400 or so I have tied up in them, especially since I could get the antennas up around 50 feet off the ground without a tower. They have stayed up in some 70-80 mph winds that snapped some pine trees in the neighborhood.

    As a final note I feed the 6,2, and 432 loops with a triplexers, one at the antennas and the other at the radios. That saves big bucks versus three low loss feed lines and the extra weight load on the support mast.

Mike WA3TTS