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Re: [RFI] MFJ-856

To: <RFI@contesting.com>
Subject: Re: [RFI] MFJ-856
From: "Dave Harmon" <k6xyz@sbcglobal.net>
Date: Mon, 23 Apr 2012 19:02:55 -0500
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
The 852 rx is the same unit as the 856. The only difference is the antenna.
I completely disagree that the dipole unit is 'worthless'.
I have both units and each have some advantages. 
It's easy to df the noise with the dipole.....when you get a null on the
meter the noise is parallel to the antenna along that 180 degree line.
Move a few hundred feet and do it again and then you can get a pretty good
indication of where the noise is coming from.
Also....I hold it out the window when I am driving along....I watch for the
loudest signal....then I stop, get out and use the unit with the yagi.
I can find a noisy pole very quickly. There is no point finding the actual
insulator....the power company guy will do that although I have done it.
It's somewhat easier at night if its dark enough....the arcs are visible is
you look carefully.
I do it this way because I can....I have both units.
If anyone is gonna buy one...get the yagi.
Its easy to track down multiple noises...you can get a direction on each
noise.
Oh....neither unit needs an attenuator.


Dave Harmon
K6XYZ[at]sbcglobal[dot]net
Sperry, Ok.

-----Original Message-----
From: rfi-bounces@contesting.com [mailto:rfi-bounces@contesting.com] On
Behalf Of Missouri Guy
Sent: Monday, April 23, 2012 11:38 AM
To: RFI@contesting.com
Subject: Re: [RFI] MFJ-856

Well, I have to check in on this....

I have the MFJ 852, the RFI RX with the "dipole.  The RX, I'll bet is the
same as the newer 856.  The 852, was worthless with just the dipole.
Otherwise it's a simple but very effective RX!

I built the 2-el Moxon antenna that was in QST some years ago.  
That, with the 852 "worked" but it too was next to worthless until I added a
homebrew ATTENUATOR.  Only THEN did it become a good RFI tracker.
 In my
attenuator, there are 3 DPDT switches for 6, 10 and 20db settings, for a
maximum total of 36db.  Sometimes that's NOT enough!  

So, I'm saying that if the 856 has a *good* beam, by all means DO add a
attenuator (say, up to 50db or so) and you'll be ready to track down the
noise!  (Hey, MFJ, are you listening?)

73,
Charlie, N0TT
 
On Sun, 22 Apr 2012 19:52:42 -0700 "KD7JYK DM09" <kd7jyk@earthlink.net>
writes:
> : However, the MFJ-856 has a signal-strength meter, and the 3-el 
> antenna
> : boom length (with the rcvr on it) may be easier to manage/handle 
> than
> : what I've been using for nearly a decade.
> 
> >From my experience and the experience of three other Hams, in the
> city,
> where noise is relatively everywhere, it is useless.  Readings are the 
> same pointing at a source, the ground or the sky when tracking down 
> power line noise.  The unit we used is now on a shelf, the parts used 
> for other
> 
> projects.
> 
> Out in the field where you may have only one noise source and you are 
> a large fraction of a mile away, it might be OK.
> 
> Kurt
> 
> _______________________________________________
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> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
> 
> 
 
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