[TowerTalk] Terrain Modeling (was choke on vertical dipole)

[john simmons]

I too feel into the 'higher is better' trap. I had a TH11 at 50' (remember I don't have a big antenna farm) and thought that if I went to 80' (highest I could go with my site) life would be much better. Nope. After some time with HFTA, negotiating sessions with my XYL and a large $$$ on a Yagi, I put up a 50' tower, moved the TH11 to the new tower at 50'. I then put a 4 el 20/2 el 40 Yagi at 80'.

Comparing the 50' 20M Yagi to the 80' Yagi is fascinating. Both Yagis have the same boom length; the 50' one is 3 elements on 20 and the 80' one is 4 elements on 20. MOST OF THE TIME THE 3 ELEMENT AT 50' BEATS THE 4 ELEMENT AT 80'.

I'm in the process of building a 10/15 stacked array per N6BT's plans. The top Yagi will be at 45', the lower one at 23'. We'll see.

73
-de "Curly" John NI0K
QRZ.com<https://www.qrz.com/db/ni0k>
Hamshack Hotline<https://hamshackhotline.com/> call me: 6100271
On 1/15/2026 3:57 PM, Jim Brown wrote:
If used extensively with good data, will tell us the relative effectiveness of mounting heights. With that information, we can make more intelligent decisions about what to do with what our real estate, budget, and other capabilities allow.

In my case, I learned that 120 ft was near optimum for EU, my most difficult direction, that a few more tower sections were not better, and that to get better, I'd need to go to at least 300 ft! :)

I also learned that 20 ft at different location on my property was a minor sweet spot for a small 10M yagi.

I spent close to a month on it. Neighbor K6XX, 4 miles up the ridge from me, used it extensively in planning his antenna farm.

73, Jim K9YC

On 1/15/2026 11:21 AM, Wes Stewart via TowerTalk wrote:
  Speaking primarily as a ham radio DXer, constrained by county zoning limits, my take on terrain modeling is, "What am I going to do about it?"  Propagation prediction is pretty much the same question.


_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk at contesting.com<mailto:TowerTalk at contesting.com>
http://lists.contesting.com/mailman/listinfo/towertalk