My experience in running digital (since 2002) is that RF can creep into the
computer and that can cause some nasty issues. I finally fixed my problem by
purchasing a properly shielded computer (a older Dell GX1). I use a home brew
OPTO isolated interface from the computer to the PTT of the radio; very easy to
make. Many computers today, especially clones, are not RF tight. There is some
conductive paint that you can apply inside the plastic covers. If you are
hearing RF trash from your computer on your receiver you can be pretty sure it
may be susceptible to interference as well. Getting rid of the CRT monitor
also helped eliminate any RFI from the computer.
Try some ferrite beads on the audio lines and the mic input; that might do the
trick but I suggest the 1:1 transformer is the best bet.
73, Bernie, Ottawa, Canada
----- Original Message -----
From: Dan Reed
To: digitalradio@yahoogroups.com ; digitalradio@yahoogroups.com
Sent: Wednesday, January 03, 2007 11:11 AM
Subject: Re: [digitalradio] New to PSK31 - advice please ??
Radio Shack some times ha isolation transformers
N0ZIZ
-----Original Message-----
From: adrianrav4
Sent: Jan 2, 2007 4:10 PM
To: digitalradio@yahoogroups.com
Subject: [digitalradio] New to PSK31 - advice please ??
Hi All
Having just moved house (& country!), and set up the HF radio gear for
the first time in quite a few years - I'm having a dabble with PSK31.
I suspect that I'm having problems with poor isolation between the
radio and the PC - at the moment the 'quickly knocked-up' interface is
'direct' - no opto or transformer isolation.
I can read the PSK31 quite nicely (using DigiPan) - and load up the TX
on low power (10W) - but higher TX power seems to generate odd squeaks
and general instability....
...also - I have yet to get a reply from any other station on PSK -
which makes me wonder if my signal's getting distorted past the point
of readability ?
Does anybody have a source for 1:1 audio isolation transformers ? I
can't seem to find them from the usual suspects (ebay, CPC...?) -
would need to be an organisation that ships to Ireland.....
Many thanks in advance
Adrian - EI5JV
