[1000mp] 1000MP Field - RTTY wiring

Wed, 28 Aug 2002 00:30:38 -0000

Fred:

My statement about the low source impedance was to warn you not to do what
you did. You combined the two signals, but. since each is the output of an
emitter follower, that essentially shorts them both almost to ground. That
creates distortion and, as I also said, you now have both signals at full
output, since the MP's AF gain controls have no effect (the output levels
are fixed). This will APPEAR to work:

* when either the DX or the pileup is transmitting, but if both are calling,
you print both.
* if you switch between RX channels with the green LED buttons; doing this,
you hear one or the other.

In the first case, you get the noise from both channels, so it does not work
very well if the DX is weak, and especially if the pileup is strong.

In the second case, you give up being able to monitor both frequencies
simultaneously.

You really want to combine the signals with a pot that is available at the
operating postiion, or with a switch and resistors to provide choices like
MAIN, BOTH, SUB.

Having said that, I have been using the second case, because my workshop is
torn apart and I have not made the little box.

My call is probably familiar to you because I have been on several
DXpeditions, and also because I tried to help with RTTY on some PY
expeditions, and also because we have worked several times on CW and RTTY.

Garry

> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of 50mhz
> Sent: Tuesday, August 27, 2002 18:16
> To: [email protected]
> Subject: ENC: [1000mp] 1000MP Field - RTTY wiring
>
>
>
> Gary
>
> Thanks for the info. I have tried the AF-out output very simply.
> I have used
> a stereo cable (with one stereo plug on each side). At the PK232
> side I used
> an stereo-to-mono adapter(short-circuited the two wires from the 2 audio
> sources). Worked wonder ! I am not sure if that is absolutely the way you
> suggested on the second paragraph.
>
> Gary, where I know your call from ? Sounds related to Dxpediton.
> I guess we
> met at Dayton too, didn't we ?
>
> Thanks again
>
> FRED PY2XB
>
> Fred Carvalho
> [email protected]
> Integral Sistemas e Com Ltda
> Sao Paulo - Brasil
> Tel 55-11-5522 2600
> Fax 55-11-5545 8246
> http://www.integral.com.br
>
>
> > -----Mensagem original-----
> > De: [email protected] [mailto:[email protected]]Em
> > nome de Garry Shapiro
> > Enviada em: domingo, 25 de agosto de 2002 22:50
> > Para: [email protected]
> > Assunto: RE: [1000mp] 1000MP Field - RTTY wiring
> >
> >
> > Fred:
> >
> > Yes, the AF OUT is the way, but with some precautions.
> >
> > * The AF OUTputs are 200 mV RMS, fixed-level; The AF GAIN
> controls do not
> > control them. A way of selecting either or mixing both outputs is
> > required.
> > A simple way is to feed them to stereo sound card inputs and use the
> > appropriate Balance control in the Windows Play Control window. However,
> > this is awkward in a pileup. A superior hardware alternative is a
> > small box
> > with a separate balance pot, at the operating position. The AF
> OUT drivers
> > are emitter followers, so their  output impedance is low.
> >
> > * You can run the mixed/selected output to the separate mono miniplug
> > labelled RXIN AUDIO on the PK232; cut the RX audio line from
> the 4-pin DIN
> > plug, or the main channel audio will always be present.
> >
> > Garry, NI6T
> >
> > > -----Original Message-----
> > > From: [email protected]
> > > [mailto:[email protected]]On Behalf Of 50Mhz
> > > Sent: Tuesday, June 25, 2002 18:25
> > > To: [email protected]
> > > Subject: [1000mp] 1000MP Field - RTTY wiring
> > >
> > >
> > > I have wired the PK232MBX to the 1000MP thru the RTTY jack at the rear
> > > panel. I have verified that only the main receiver audio is
> > routed to the
> > > PK232 via RTTY connector pin 2. This avoids the use of the
> > > sub-receiver and
> > > therefore makes not possible to monitor the transmitting side
> > of the RTTY
> > > pile-ups with the sub-receiver.
> > >
> > > I can overcome this problem by using the AF-OUT output where
> > both receiver
> > > audio are present. Is this the way ?
> > >
> > > I would appreciate feedback on this and information how you
> have worked
> > > around cases like this.
> > >
> > > Thanks de PY2XB, Fred
> > >
> > > _______________________________________________
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