[NLRS] Left Field (or maybe even outside the ball park)

[Dr. Gerald N. Johnson]

On 6/17/2013 7:57 PM, Richard Clem wrote:
>
>
>>>> Some radios have line level in and out for data in SSB and FM modes, The
> FT-857 for one so all it takes is the 6 pin mini din cable split out to
> a pair of stereo plugs for the sound card. I used a Yaesu CT-39A cable
> which is just a 6 pin mini din to bared wires. Surely there is a 6 pin
> mini din universal cable in the audio shops that can be cut in half and
> spliced to a male to male stereo cable cut in half. Same cable fits a
> TS-450 I think. The 857 has provision for VOX based on the transmit data
> tone to keep the connections really simple and it works well.<<<
>
> I'm guessing the FT-857 is identical to my FT-817, but my PSK-31 interface
> consists of the plug cut off an old computer mouse, with a miniature plug on
> the other end.  It also has two resistors, one fixed and one variable.  Since
> the FT-817 doesn't have "digital VOX", I just use a switch to manually switch
> from transmit to receive.  The receiver audio goes directly from the rig's
> headphone jack to the computer.  I think I used the AUX input of the
> soundcard.  It's about as primitive as can be, without using coconut shells or
> something.  The original site where I got this is gone, but here it is via the
> Wayback Machine:

The 857 is not exactly the same as the 817. Digital VOX is one, another 
is allowing CW operation in SSB mode merely by closing the key, no need 
to change modes, just use the key and it transmits CW. You do have to go 
into the menu and enable that and also set the direction of the offset. 
Works super on VHF where mixed mode contacts are often made, but when 
its set for USB shift and I call a station on 40 m CW they don't hear me 
until I go to the menu and change that automatic shift direction for 
that handy mode shifting.

AUX is line level input to the sound board and the correct input for the 
line level output of the radio.

Some of the PS/2 extenders also have only 5 wires so I've not used one 
of them yet. There are mini-din 6 and 8 pin cables on epay wired 
straight through male to male. Mouser has sold mini-din chassis 
connectors with wire leads attached, but last week I bought a switch box 
with 5 8 pin mini-din chassis mount connectors and a mini-din 8 pin male 
to male for hooking up the relay controls to use separate PAs for 2m and 
432 with my 857. I'll use the box and one of the connectors, and put RCA 
jacks for the cables to the Mirage amplifiers, and something for keying 
the relays that will select the amps. Relays will have a bit lower loss 
than filter type duplexors. Though I think the duplexor up on the roof 
has failed because 432 contacts were really hard to make last weekend. 
Water has a molecular resonance near 520 MHz and so is a lossy insulator 
at 432 MHz.
>
> http://web.archive.org/web/20110702100606/http://members.cox.net/jrehak/DirtSimplePSK.htm
>
> For PSK-31, I just set the levels so that the rig's ALC was not kicking in.  I
> think I even turned it down a little bit below that point, so it's definitely
> QRP.  I worked all states with that setup, including KL7 on 80 meters.


Not kicking in ALC is a standard test level, but others watching your 
spectrum on the waterfall will let you know if you drive the rig too hard.
>
> I don't have any isolation transformers.  I was warned that I would get 60
> cycle hum by doing it this way, but that hasn't been a problem.  I don't see
> why the resulting audio couldn't be sent via FM.  I don't know what the mode
> would officially be called, but it would certainly be digital.

Hum can be a problem with the microphone input because its at a level of 
a millivolt or so, while line level can be a volt or two. 60 dB less 
sensitive to ground loop hum.

>
> I don't have the PSK-31 software installed on my computer right now, but if
> someone wants to give it a try, just let me know.
>
> 73,
> Rick W0IS
>
73, Jerry, K0CQ