On 07/25/2010 06:10 PM, Antonio Vernucci wrote:
Are you testing into a dummy load?

yes, 50 ohm

If you have an antenna impedance bridge you may be able to measure the
effective impedance of the output stage. If the transmitter is
operating normally you may need some sort of external tuner.

I like to operate boatanchors in the way there were supposed to operate.
So, if the ART-13 was not designed to operate on the 80 / 75 MHz band
with a 50-ohm load, I'll just give up.

What I would like to know is whether all the ART-13s behave that way, or
I should instead suspect that a problem occurs on my particular ART-13.

So, I am looking for somebody who can readily fire-up an ART-13 and
confirm or deny my experience.

73

Tony I0JX

In the CQ surplus conversion manual, the one of the chapters on the
ART13 refers to using a 118' flat top antenna feed with a single wire
feeded 17' off center (windom?). The author claims on 80 it acts as a
singe wire feed matched impedance half wave. On 40 and 20 it is a large
T type Marconi. So someone got the rig on 80, but using an old style
wire antenna. I suspect using a modem coax fed antenna with this rig on
80 may be a problem.

Also note that art13's can't normally reach 10 meters, but they have
been converted to this in several ways. One way was to install and
extra multiplier stage where the optional low frequency unit would have
been installed. An extra 10 meter tank coil for the 813 is also added.
Operation on the lower bands is not affected.

There is something to be said for leaving the rig as it was in the
airplane, but I suspect most hams modified these radios somewhat to make
them more useful for civilian use.

Check on the ARRL website and search the QST back issue index for
articles from the late 40's through early '60s and you should find some
articles on the ART13.