RES: [1000mp] 1000MP Field - RTTY wiring

Wed, 28 Aug 2002 12:17:30 -0300

Gary

Answers/comments in-line

> -----Mensagem original-----
> De: [email protected] [mailto:[email protected]]Em
> nome de Garry Shapiro
> Enviada em: ter�a-feira, 27 de agosto de 2002 21:31
> Para: [email protected]
> Assunto: RE: [1000mp] 1000MP Field - RTTY wiring
>
>
> 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:
>

I got your point . However it did work ok.  The decoding seems to be perfect
without any noticeable distortion on both VFOs. I have not notice any major
problem. But I understand we better avoid that

> * 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.

Actually you never get to decode both signals correctly. So, to correctly
decode one or another you need to switch to main/sub anyway. However it
seems to be easier to track the calling station using the sub-receiver when
the dx frequency is calm.

>
> 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.
>

Finally Gary, the advantage to use the sub receiver is limited to a certain
cases. Perhaps the old fashion way to select individual VFOs is still a
reasonable way.

> 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.

You know Gary, I have a terrible memory for calls but yours is l well kept
in my mind. Thanks for being on the dxpeditions and thanks for helping my
countrymates with the rtty operations. Best regards

>
> 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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> > >
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> >
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>
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