The 160/80/40 antenna is an Alpha Delta DX-B sloper, which uses the tower as a counterpoise. You may be correct. I do see a slight null, but only about 2 S-units. If I really want to knock the noise down, I can turn down the gain of both antennas, but then I'm not hearing anything.

Spent the day trying different noise antennas, run a wire parallel to the sloper, across the yard, around the roof, in none of the configurations is the noise antenna hearing the same signal the sloper is. So needless to say I am not getting the results I was expecting. May be time to give up 160 and 80.

The more I think about it, the more I think the issue is with the sensing antenna. I don't think using the center conductor of a length of coax will cut it. Problem is I can't get up the tower to hook it to anything. I am going to try my scanner antenna (it's a vertical) to see how well that hears the noise, but need to run that coax into the new shack before I can try it.

I would ideally like to run a wire parallel to the sloper, but not sure I can do that. I can run a longwire (a real one) from the chimney over to a tree and down to the pole where the end of the sloper is attached. This will at least get the sensing antenna over to where I think the noise is coming from.

As a test, I put the rig on 1.955, where the interference is the worst, and switch between the sloper and beam. They both hear the interference differently. On the sloper it is just a loud 20 over 9 buzz. On the beam its about S7 but does not have the same buzz characteristic. I think this is what the current sensing antenna is hearing.

Go the unit hooked up last night, unit is set up through the RX ANT loop on the FT-990. Currently I am using what amounts to a longwire antenna (the center conductor only of an used run of coax that goes up the tower) for the sensing antenna and the sloper as the main antenna. Interference problem is mainly on 160 and 80. Adjusting the noise antenna gain does increase or reduce the noise, while adjusting the main gain does the same on the signal. I have tried all different settings, followed the instructions to a "T" and cannot get the noise down more than a couple of db, say from 20 over down to about an S9. There is no deep null as was expected.

If I listen to the offending signal on the regular antenna, it is a very pronounced buzz, very easy sound to distinguish. When I turn up the noise antenna gain, the interference does not sound the same, it's more like hashing or a wider type of noise, so I'm not sure if maybe the problem isn't with the "noise" antenna. Just to test, I reversed the antennas, used the sloper as the noise antenna and the longwire as the receiving antenna. Still the same results.

So before I go stringing up another antenna, am I doing something wrong? I also hooked the unit up direct, antenna to unit, unit to antenna connector on the radio (not through the RX loop) and had the same results.

Any suggestions?

Max

I was thinking about what  I would use for the sensing antenna. On the tower I currently have an HF beam and sloper off the side. I use both. I have one unused coax hanging up there that fed a 2m beam at one point. On the sloper, the offending noise is 20 over 9 all across 160 and most of 80, where the interference is strongest. Just for a test, this morning I fed just the center of this unused coax into the radio and the signal strength was also 20 over so I think this will make an okay sensing antenna.

I really wish I had a KW amp so I could get some high power out there and let them know how it feels.

Thanks for the encouragement. I'm sure it will help. My antenna isn't very effective on 160 but I do like to listen. The noise is particularly strong on 1955 about 30 over. But the noise carries through right up into 40m. Very annoying.

73,

Hi group,

I have an MFJ-1026 on the way, hoping to squash the Plasma RF problem. The rig is a Yaesu FT990 and it has the RX antenna in and out jacks on the rear. I read somewhere these jacks can be used  with the 1026. I prefer to go this route, rather than put RF through it. Anyone have any experience with this?

Thanks,
Max

Well I figure for the few minutes it takes to alert other hams, it's worth my time.

I really don't mind. Sorry my post took a few minutes out of your day.

I posted an ad on another site looking for an MFJ-1025/1026 or ANC-4 noise canceler. I received an email from a ham using the call KE4EPT. Right away the language threw up a flag:

Hello ,
How is your day going?
I saw your WTB advert,that's why am sending this mail.
I have MFJ-1025  up for sale in an excellent condition.
Looking to read back from you soonest.
73

Just for fun I asked him if he could send a picture and what was his asking price (not telling me his asking price in first reply was another flag). He responded with a picture, and the following:

100% working condition with minor scratches to the top of the cabinet.Comes with power cord and copy of manual.
100$ shipped.

So on a whim I decided to search the net for the picture and found the exact same picture and ad text from an ad posted on this site in 2010 (unit sold). I emailed the "seller" back and told him I found the exact same picture from an ad in 2010, his response was:

I dont have a pic of mine for now... and that 1 looks looks exactly like mine.

Just for fun I asked him where he wants the money order mailed and what is his name. We'll see what he comes back with.

Beware!

Never seen a topic get more off topic in my life!

Thanks I'll take a look inside.

Excellent advise, I can get up to the 13m shortwave band on AM on my portable receiver. Waiting for some time to get through the neighborhood. I am just hoping it isn't some consumer electronics in a neighbors house, and maybe I get lucky and it is a utility pole.

Thanks for the tip.

Glad you tracked it down. I have a similar issue now with massive interference from the upper end of the BCB to just below 40m. It is about 20-30db over 9 on 1.995 MHz. Seems to have started just after Christmas so I'm thinking one of my neighbors must have picked up some cheap Chinese electronics for boxing day. When it warms up a bit I'll walk the neighborhood with my portable Grundig and see if I can pinpoint it. If it's coming from the house I think it is I'll be SOL. Called the cops on that guy a few years back after I caught him dumping his leaves over my fence!

I've posted a new video of the interference. The interference is all the same noise just depends which antenna I am hearing it on. The noise blanker does a good job of knocking it down but still puzzled by it's source.

Here's the link for the video:

 http://youtu.be/FBWZHNOifA8

Max