[Lowfer] Antenna mod at M P

[Mitch Powell]

Jon:

Yes - I built a 7 foot dia. "octoloop" using 1/2 inch copper pipe.
Burhans preamp.   Did some testing at mid-afternoon.
Had a branch at about 35 feet up - and in the clear.....
tied the rope to the top of the loop and kept increasing the height in 5 ft steps,
while checking signal strength on a couple of NDBs, noting the signal strength and the
background noise leel. At 35 feet - the bottom of the loop ( the preamp was at 28 then )
Can't find the actual records now - but as I remember:
5 feet off the ground - readable signals for reference - and low noise level.
10 feet off - signal increasing - nothing significant in noise level.
15 feet off - increasing signal strength - and noting a little more noise in the background.
20 feet off - signal strength seemed to level off and noise slightly stronger.
25 feet off ( 28 ft ) not much improvement in signal strength - and noise levlling off.

That's pretty subjective - but that's as I remember.
Now - the 12 foot "octoloop" resulted in much stronger signals without noticeable change in
noise level - and is mounted with the preamp at15 feet.... with a rotator driving the 2 inch
aluminum central pipe. 

Right now I am using the W1VD modified active antenna - base at 15 feet - with separate ground wire to ground pipe -
and W1VD DC coupler.  Having great luck with it - and gives me HF as well.

I have been using the active to find NDBs or signals then switching to the loop
for logging and capturing.

Hope that helps.

Mitch
On 2012-11-11, at 10:43 AM, JJ wrote:

> Mitch,
> I'm curious...Did you compare the Burhan's from mounted at ground level 
> to elevated and if so what were the results?
> 
>> 
>> Jon: I'm using the Burhans setup, with a 12 foot octoloop . Nice antenna, and
>> very directive - up 15 feet.
>> 
>> Thanks again all.
>>