[Milsurplus] The ART-13 revisited

[Pete Williams]

Seasons  greetings.. After being very idle for 35 + years in my storage  the
ART-13 ex RAAF  came out for a wash and polish---- I had set it up with the
dyno and a  CDA xtal unt installed I got  from Robert Downes  but the  DC
supply always a problem and  seldom used impressed the odd visitor  tho'.
 I made an  AC supply, ideas from various sources ..., AOK in the
operating/generation of  RF---- however, no matter what, listening to the
carrier on both TUNE  and OPERATE via  the R-390A, the  hum was, to my ear,
somewhat objectionable . Any FM'ing minimal as BFO note pretty pure . we are
50 Hz users in OZ.
I've used 28V from batteries to light the  heaters  as a check, and revamped
the  2 section filter in the 400v supply. Hum reduction  negligible  from
all these actions --- Thinking of  some form of overload in the  R-390A, the
antenna  reduced to a short  wire----- no difference .
I've been a bit  diffident  about putting it to air to get a  comment---- in
the interim, I'd take input  from anyone having  gone this  route and has
done  anything special to  alleviate any similar problem. The only  thing I
haven't  tried is  a separate ground for the AC  supply and tx..
To reiterate .
1.  Hum is  evident  on carrier  on calibrate ,  tune  and operate.-(phone
of course- we've outlawed CW here !)

2. The 1000V adds nothing--- it's not used in tune .

3. Hum on sidetone via  phones.

4, Maybe an on air  comment the only way to go  and leave it as is if not
tarred  and feathered  come 2008.
Finally. I can't  say how impressed I am with the  frequency accuracy of a
60 year old plus tx...... setting the frequency on 3600 kHz per the  book,
only put it out by 520Hz as measured on my counter! Remarkable .
With all best wishes for 2008.

Pete VK3IZ
jupete at bigpond.net.au