[TowerTalk] stacks on 40

[Dave Sublette]

I wish I had the expertise with computer analysis that is being displayed during this discussion.  If anyone would like to do some analysis on my location, I would love it.  For 28 years, until last Fall, I had a Rohn 55 tower.  It was 200 feet tall and the top 150 feet rotated using the RTS hardware.  I had 2 element Cushcraft 40 meter yagis at 70 and 140 feet. My guy rings were at 100, 140 and 190 feet to accommodate this arrangement.  I did do some analysis with a computer program before I put it up.  I think it might have been the K6STi software, but it was 30 years ago.  What I found was that the  f/b ratio of the 2 element yagi was typically 10 dB or so … when I added the second yagi, and only at the heights of 70/140 feet the system f/b went to 20 dB.  So that’s why I chose to do it that way.

I cannot tell you that I did that analysis properly.  Further, I’m sure it was simulated over flat ground, not free space.  At this location, I am nearer to free space than over flat ground.  My Qth is on a ridge, the highest point in the county.  I am higher than average terrain for 30 miles in all directions.  The view from that tower was spectacular.

Now here is the sad part and probably should be entered in a psychoanalysis reflector.  I didn’t use it all that much.  I didn’t have a BIP BOP — whatever switch.  It was hard wired in Phase.    I never ran more than 100 watts and the phasing coax was RG8X.   I worked everything I heard with one call.  I made probably less than 1000 QSOs in 28 years.  I worked a lot (relatively speaking) of QRP.  Again — most were one call QSOs.

So I had the tower taken down in the Fall because the doctor doesn’t want me climbing.  Since then I have begun to feel a lot better and am climbing to 60 feet regularly.  I’m putting the tower back up to 155 feet and the rotary joint five feet above ground so I don’t have to climb to  work on the motor/gearbox.

Again, I plan to put a pair of 40 meter two element yagis. This time I think it will be the Moxon.

The tower is at 55 feet right now, awaiting the installation of the first guy ring.  The tower should be up by the end of the Summer.  I have a good friend who is doing the tower work while I drive the tractor.  When it’s up, I have a design in my head for a power winch for permanent installation on the tower.

So if any of you would like to take a crack at some analysis, now is the ideal time.  My private email is my call at arrl dot net.  I would love to work on this with some experienced guidance.

73,

Dave, K4TO


SNIP