[ADXA] 6-Meter Antenna Height

Tue Jun 10 16:01:56 EDT 2025

I think the GodFather also claimed you might get more ground noise going above 50 feet?  I do trust Frank on this, but I violated that on my last 6m setup.  I guess if you are into very super weak signal work, then that is something to look into, but at my location, I usually have other noise issues!

Great stuff Joel!  73 de w5jay/jay..
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From: adxa-bounces at mailman.qth.net <adxa-bounces at mailman.qth.net> on behalf of w5znjoel at gmail.com <w5znjoel at gmail.com>
Sent: Tuesday, June 10, 2025 6:46 AM
To: 'ADXA' <adxa at mailman.qth.net>
Subject: [ADXA] 6-Meter Antenna Height

CAUTION – This is a long email.

I received several nice comments regarding my article on 6-meter EME. Thank you.

One question was central to all of the comments; How would the EME array work terrestrially?

I’m pleased that question was asked, and it almost warrants another paper as I have a large amount of data on this topic for 6-meters, and simulation results need to be presented as well, but I’ll explain here.

When I was heavy into VHF contesting, I utilized several different 6-meter antenna configurations, most were based on the work by my good friend Dave Olean, K1WHS the founder and original owner of Directive Systems. Dave built an impressive multi-op VHF contest station on a hilltop in Maine operating from 50 MHz thru 24 GHz. I was invited to be a team member for the September contest in 2011, the year K1WHS beat the perennial winner in the multi-op category, W2SZ. Having seen and operated from Dave’s station, and studying his antenna arrangement gave me a lot of good ideas to use for my station.

I have had four 6M7JHV’s (yes the same four referenced in the paper) stacked at 27’, 52’, 77’, and 102’ that I could switch individually, in pairs, or all four together. I have had three 6-meter large vertical arrays (LVA) which is simply four 3-element Yagi’s stacked vertically and fed all together. These are meant to be fixed in one azimuth direction that will produce a very low, sharp patter in the H-plane (elevation) but be extremely broad in the E-plane (azimuth) so with three LVA’s fixed in three different directions you effectively cover from California, thru north, to Florida and the Caribbean by simply and quickly switching antennas without rotating. These were all mounted between 30 to 50 ft high. Those who were here for the ADXA meeting a few years ago saw this array. Being way up in Maine, Dave only needed one (he had 8 stacked) to cover the entire USA!

My current 6-meter terrestrial antennas, which those who were here this past September saw, includes three M2 6M9KHW’s. One on top of the tower at 110’ feet rotatable, one at 83 ft fixed to the NE, and one at 56 ft fixed to the NW. These can all be switched individually, all three together, or in pairs. The concept is to be able to switch, without rotating, to three different directions quickly in a contest. With the middle antenna being fixed to the NE (that was planned), I could rotate the top antenna to NE, phase the two together and basically have a “blow torch” to EU.

I have documented data from 25 years of 6-meter antenna comparison here in Arkansas. That’s an important point, because if you are going to compare antenna performance you can NOT accurately do so with another station or from a different location hundreds of miles away. There are just too many variables that factor into the comparison equation.

If you’ve stayed with me so far, here’s the results summary.

Only on a very few rare occasions did one antenna, at a different height, produce a signal I could not copy on the others. What was very apparent is when I would switch between the antennas at different heights the noise level would be different. With that said, and this is why a paper would be order, is you must look at simulation results from antenna models at different heights and understand what happens the higher you go. You will develop many more nulls in the H-plane (elevation pattern) so depending on the arrival angle of the signal it may appear in a null.

So, what about using the EME array for terrestrial work? The center of my EME array is at 27 ft. That was not by accident. The optimum height for a 6-meter antenna for Sporadic-E is 27 ft. Depending on the propagation mode a higher level may be optimum. The Godfather (my code name for Frank, W3LPL) says around 50 ft is a great height to cover all propagation modes (Es, F2, MS, etc) and I don’t dispute that……..I may question, but never dispute, the Godfather!!!  ?? By the way, when it comes to HF antennas K5GO is a co-Godfather or, as a minimum, a senior Captain!!!

Over the past months since I have had the EME array in operation we have had some very nice 6-meter openings. I have compared terrestrial signals on the EME array to all of my current 6M9KHW’s. K5EJ is about 20 miles north of me and has a 6M9KHW around 100 ft or so high and we have compared received signal levels in almost every band opening over the past year so this is excellent data for comparison. There are times when EJ decodes a DX and I can’t, then there are times just the opposite. There are times when his decode is much stronger than mine, then there are other times just the opposite. Conclusion – location, propagation mode, and arrival angle based on a specific location determine what you will hear (or decode).

My EME array has consistently outperformed the 6M9KHW’s on my tower BUT that requires some explanation. The EME array is four antennas that has around 5 to 6 dB more gain than a single 6M9, and more than two phased together. My EME array is out in the open without adjacent trees or buildings. I basically have a clear shot to EU, SA, the Pacific, and JA with the array at 27 ft. I can elevate the array, so maybe a little 2 to 5 degree elevation tilt helps at times.

To give you an idea of how convinced I am regarding the performance of the EME array for terrestrial work, this summer I plan to remove the 6M9KHW’s. What does that mean for you and your location? I can’t answer that question without evaluating your specific QTH but if you can only erect 6-meter antenna 30 feet high don’t assume it’s a lost cause.

Now, GET IN THERE AND WORK ‘EM!

73 Joel W5ZN

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