Topband: Monopole Elev Pattern w.r.t. Earth Conductivity

[Tom W8JI]

Herb's experience below echoes mine at my house here in GA and at BC 
stations in the Midwest. Others besides Herb have reported the same.




----- Original Message ----- 
From: "Herb Schoenbohm" <herbs at vitelcom.net>
To: <topband at contesting.com>
Sent: Wednesday, October 24, 2012 6:58 PM
Subject: Re: Topband: Monopole Elev Pattern w.r.t. Earth Conductivity


>I used or tried to use a 308 foot self supporting base insulated Blau-Knox 
>in the late 70's and early 80's (Picture on QRZ.com) and although I could 
>not do A-B tests I found it horrible and that was over a 2 degree  buried 
>260 foot radial ground system for 970Khz right next to the ocean.  I found 
>better use for it by using it to run a rope up to the top and hung 1/2 wave 
>slopers down to the sea, and that was much better for RX reports on 160 
>from Europe.  I really expected better results but was amazed at the 
>difference over many years of testing.  I would drop the sloper(s) to the 
>ground when trying to use the 308 foot free standing tower...which the 
>books said would be an optimal low angle radiator.  The slopers and even a 
>full sized corner fed delta loop were always much better.
>
>
> Herb, KV4FZ
>
>
>
>
> On 10/24/2012 5:44 PM, Tom W8JI wrote:
>>> Did you --or anyone else you are aware of-- ever A-B test a ~120' tower
>>> against a ~300' tower on 160?
>>
>> I A-B or A-B-C tested several antennas, including a low dipole, the high 
>> dipole, an element from my four square, a ~318 foot insulated tower 
>> vertical, and I think my tall omni vertical was about 190 feet at that 
>> time.
>>
>> The tall vertical tower was definitely worse compared to shorter 
>> verticals, and had almost no short skip signal around Georgia. I had 
>> isolation chokes for lights and a base insulator, but that 300+ foot 
>> tower was so poor I never used it as a vertical.
>>
>> By the way, to show how bad interaction is, I had to detune unused towers 
>> even when they were 300 feet or so apart.
>>
>> If you recall W8LT and the balloon verticals, they didn't do so well with 
>> that antenna at 5/8th wave. I used WSPD, WOHO, and WXEZ (King Road 350 
>> ft) towers also, but had no A-B tests.
>>
>> Anything tall or new received good reports, if I told the other person it 
>> was tall or new. This is a common result, similar to the well-known G5RV 
>> effects. Pick an unpopular antenna like a G5RV and say you are using it 
>> in a test, and even if you do not actually switch antennas the G5RV will 
>> get a weaker report over long averages of tests. You can see a similar 
>> effect with guest operators and a no-change switch position. They always 
>> like the better antenna, even when it is the same antenna.  :-)
>>
>> To avoid the G5RV effect when making A-B tests, I never said which 
>> antenna was actually A or B. I also would randomly change A or B around 
>> in different tests. Just watching reports without changing antennas at 
>> all is interesting.
>>
>> 73 Tom
>> _______________________________________________
>> Topband reflector - topband at contesting.com
>
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