Topband: Directional Receive Antennas

[W2pm@aol.com]

I have been diligently experimenting with receive antennas here in suburban, NOISY, NNJ for several months and have carefully studied the many great posts here as well as ON4UN's book and other sources.  I have a 1 AC lot in a neighborhood with buried utilities EXCEPT for a 12KV power line feed thru my rear yard about 100 ft from the back of the house. The line runs E - W and my property ends just behind the cable swath making any directional receive antenna to EU (45 deg) having to "look" thru those lines - not very nice.  Also, my Inv L runs parallel to those lines with a 40' separation so you can imagine the noise level from the tx antenna! Somehow, however, several magnetic receive loops (round and square) AND a full size pennant have ended up in the woods behind the 12KV line. It didn't hurt to paint the supports for those with brown and green paint.. I have also built a HALF SIZE FULL FLAG - 7 X 14.5 ft thanks to Steve, VE6WZ (see his web site - www.qsl.net/ve6wz/flagscalecomp.htm) and have tested it fairly extensively finding it to perform very closely to the EZNEC model - verifying the deep 40dB sharp rear null and seemingly fairly wide 147 deg beamwidth.. It does have very low output tho - minus 44db - (but better than the mag loops) so my ICE preamp works double time here.  I also use Gary K9AY's very FB 16:1 xformers which are a dream to build with. (had to paint them camoflage too)  

In a very noisy small lot situation nulling to the noise is THE LIMITING FACTOR - hence the (stealth) placement BEHIND the 12KV lines to EU and in front of them with the Mini Flag to VK/ZL.  The mini flag is very easy to build and rotate too. I have found that the null is sharp enough to nearly null out a strong BC stations less than 15 miles away with the S meter going from s9 plus to S1 or less to the rear.  I have seen this on W1AW 1818 too(less than 100 mi NE) - going from S9 to S0. The magnetic loops are great for nulling to 12KV noise source but still provide considerable pickup in a far wider "beamwidth" than the mini flag - I have tested the loops vs the mini flag on 160 and noted the considerable S/N improvement from the cardiodal pattern.. And on 80 thru 30 the effect is even better as the output is greater (no preamp nec) This is an excellent rotatable low noise antenna for small lots..

By far the full Pennant (and I also tested a full FLAG) are much better because of the greater outputs but the XYL has used several unflattering adjectives to describe the property after installing them in the clear back yard..  Altho I still think the full Flag would make a neat volley ball net properly disguised.

So my recommendation is consider BOTH a mag loop and a mini flag, and by all means get a MFJ1025 nuller - on a small noisy suburban lot you need all the help you can get.. BTW - I have worked 29 countries since early December including VK and KH6, AF and the usual easy ones from EU -- could never have done it without the RX setup here..