A similar method has been in use here for a couple years. It let me snag VP8STI among others underneath a big noise last winter.
This year, I made a wire flag for 80/160 as a noise pickup antenna, and pointed the null 180 degrees away from the noise source(s). The flag is routed to a variable gain preamp before the phasing unit. It appears that adding the noise pickup antenna, can add lobes or skew the pattern of my 4 square rx antenna. That doesn't mean that the desired signal's SNR won't be improved. Often it is. Prior to the flag, bogs were being used here as the pickup antenna. I still use them when the signal can be improved from polarity diversity. . de Art NK8X ᐧ On Sat, Dec 3, 2016 at 9:01 AM, Tree <[email protected]> wrote: > Last night - around 8 PM or so - this HUGE noise signal showed up on 160 - > sweeping up the band slowly. Probably a DC power supply with signals every > 80 kHz or something. But - it has some energy all over the ban - thus > rasing my noise floor. Sorry if I was an alligator last night. > > I put a Beverage up to the East just before the contest started - so I had > two RX antennas - the other being a Hi-Z 4 square. The Hi-Z said the noise > signal was East - perhaps a bit stronger in the South direction than North > - so call it just South of East. The Beverage picked it up very well - so > it agreed. A feeble attempt at DFing last night was unsuccessful - but > will be tried again if it stays on during the daytime. It is still on this > morning before Sunrise. > > The nasty part of the noise is about the same signal strength as most good > signals coming in that are not local (looking at the band scope). It has a > 10 kHz or so wide peak. > > I was able to put the two RX antennas into a MFJ-1026 - with the output > going to the RX input of my K3 - and adjusted the controls to null out the > noise. With a local signal - I have been able to obtain deep nulls and > this proved to be true with this noise. I was actually running guys on the > East coast right in the middle of the worst part of the noise after doing > this. > > This technique would likely be useful for those who have a similar noise > situation - so I wanted to share. You obviously don't need a beverage for > the "noise" antenna - just something that is good at picking up the noise > and perhaps nothing much else. If you have a neighbor that has a noisy > device - just put something that is close to their house. > > It's a battle out there to keep your noise sources under control. I'll > report back if I am successful in finding this one. > > 73 Tree N6TR / K7RAT > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > _________________ Topband Reflector Archives - http://www.contesting.com/_topband
