[TowerTalk] 6-meter antenna height

Jim Brown jim at audiosystemsgroup.com
Sun Jul 31 04:44:43 EDT 2016


On Sat,7/30/2016 10:50 PM, Roger (K8RI) on TT wrote:
> Keeping in mind that the ideal height for HF is statistically derived, 
> where is the point (frequency) where we should typically be switching 
> over from the way we figure HF antenna height to the higher the better? 

I've worked 6M since I was a kid -- I was in WV for the great 1957-58 
solar cycle when we worked South Africa in the morning, then W6, then 
KH6, and then JA. For weeks at a time! It was all AM, and 50W was high 
power. I also worked a lot of AU on 6 in those days all CW, of course.

I worked 6M again from Chicago in the '70s the'80s, and the '00s. 100W 
and a pair of PAR loops at about 50 ft. I remember working a guy in Long 
Island with an antenna in his basement, and he had a pretty good signal.

Before I had a SteppIR at 120 ft, I loaded high 80/40 fan dipoles on 6M 
and made at least a couple of dozen double hop QSOs, including at least 
one KH6.

6M is primarily tropo and Sporadic-E, and sporadic is the key word. We 
don't even know the mechanism that establishes a cloud in the E-layer, 
and I strongly suspect that we want to hit that cloud at various angles 
depending on how far away it is. But I'm only guessing. I've worked no 
AU from my CA QTH -- I'm too far S. But I have worked some meteor 
scatter and tropo. My guess is that higher is better for these modes, 
but again, I'm guessing. Tropo, for example, includes ducting.

My QTH is looking into a ridge to the N, E, and SE that rises 200 - 600 
ft from my ground level, so higher is better. That SteppIR at 120 ft 
gives me a horizon between about 12 and 15 degrees to all of NA. And 
it's looking into a dense stand of redwoods in all directions. But I've 
still managed to work 352 grids and confirm 342 in ten seasons. This was 
a bad season, and it still yielded 11 new grids.

73, Jim K9YC



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