Instead of placing the Preselector in the antenna line, why don't
you connect it directly in the RX circuitry - specifically just
before the input bandpass filters. All you need is a couple of
RCA phono jacks on the back panel. Then QSK will work just fine
because you don't have to switch the Preselector in and out.
73
Rick
-----Original Message-----
From: tentec-bounces@contesting.com
[mailto:tentec-bounces@contesting.com]On Behalf Of old neta
Sent: Tuesday, December 16, 2003 5:24 PM
To: tentec@contesting.com
Subject: Re: [TenTec] Preselector/Jupiter
The MFJ-1040B is an active preselector. I have used it and it
works.
At 50.1 MHz it has some VSWR on transmitt.
It has a relay so you can not QSK.
I was using it to keep out a strong local station at 1100 kHz.
Now I have a Industrial Communications Engineering, LTD
Model 402X highpass filter that does a better job of filtering
the 1100 kHz station.
I turned up the IF gain all the way to improve 28120 kHz psk31.
I only have a vertical so I need every bit of gain I can get to
get the
weak signals.
Jim FitzSimons W7ANF
----- Original Message -----
From: "Bill Miner" <wg6h@postoffice.pacbell.net>
To: <tentec@contesting.com>
Sent: Monday, December 15, 2003 19:14 PM
Subject: Re: [TenTec] Preselector/Jupiter
> Bob,
>
> The MFJ passive preselector is a low Q device with only a
single series
> tuned LC circuit. I have tried one on my T-T 1254 SWL receiver
with
> some improvement but the 1254 has only a broad bandpass filter
for the
> entire HF band. I believe the Jupiter has bandpass filters for
each
> amateur band and probably would not really benefit much from
the MFJ
> unit.
>
> A multi element high Q preselector might be of benefit but I am
not
> aware of any off the shelf units so it would have to be
homebrewed. Not
> sure it would be worth the effort however.
>
> 73,
> Bill - K6WLM
>
> Bob Stephens wrote:
> >
> > I'm wondering if anyone has tried using the MFJ passive
transceiver
> > preselector with a Jup/Peg or Argo V during a contest ? It is
supposed
to
> > increase dynamic range. Is it effective ?
> >
> > tnx & 73
> > Bob KB1CIW
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