Hi Dale.....
I don't have a sig generator that goes high enough...about 144mhz...so I
can't test it.
All I know is that I can find what I am looking for when I use it.
I use a pair of earbuds as well.
Dave Harmon
NSRCA 586
K6XYZ[at]sbcglobal[dot]net
Sperry, Ok.
-----Original Message-----
From: Dale Svetanoff [mailto:svetanoff@earthlink.net]
Sent: Monday, April 23, 2012 9:48 PM
To: Dave Harmon; RFI@contesting.com
Subject: Re: [RFI] MFJ-856
Dave and Charlie,
Well, you guys appear to be agreeing to disagree, at least insofar as use
(or not) of an attenuator goes. Question: Has either of you ever put
either MFJ unit onto a sig gen and measured the dynamic range of its meter?
While I respect both of your opinions, I'd respect them more if I knew 2
things: 1) What is the usable metering dynamic range of the MFJ units? 2)
What was the actual field strength of the RFI each of you was tracking at
the point of closest approach to the source?
Without knowing more data, I will take Charlie's side and suggest that an
attenuator should at least be available for those times in which you "run
out of meter". If a given receiver never runs out of meter on even the
strongest signals, I submit that it has then gone into gain compression.
Granted, we do not need to know the actual field strength in order to solve
the question of what and where is the RFI source, but we do need to know it
if we are to get usable empirical data on the performance (or lack) of these
RFI receivers.
73, Dale
WA9ENA
> [Original Message]
> From: Dave Harmon <k6xyz@sbcglobal.net>
> To: <RFI@contesting.com>
> Date: 4/23/2012 7:03:01
> Subject: Re: [RFI] MFJ-856
>
> 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
> >
> > _______________________________________________
> > RFI mailing list
> > RFI@contesting.com
> > http://lists.contesting.com/mailman/listinfo/rfi
> >
> >
>
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|