I have a MARCONI Q-Meter set. The manual says that a special cable
is needed to connect the generator to the measuring part. I do not
have this "special" cable. Now my question: what is special about
this cable ? How can I built one ?
Claude
Hello Claude,
you may have better luck with your question on this group
rec.radio.amateur.boatanchors
I have a generator TF1246 that bolts on to the side of
a number of other measuring instruments, or can be used
on its own.
The output circuitry of this generator is nothing special,
but the front panel does mention
"for 50 ohms use matching unit TM5726"
which I am guessing is just a little box with a coax cable
that goes to the generator and contains a little resistor
network to give a much reduced output level somewhere
near 50 ohms output impedance to drive the associated
measuring instrument.
Open up your generator unit and check if the output
connector goes to a potentiometer, which means that
the output impedance is all over the place, which means
the connecting cable need not be anything special at all.
Maybe this "special cable" is like the matching unit
referred to on my generator. I am guessing here, Claude,
give us some equipment type numbers. Someone may
have an old Marconi test equipment catalogue.
You could try e-mailing Marconi Instruments, I did have
success a couple of times when I wanted parts for an
old CRO and old signal generator but the cost was
rdiculous. A couple of years ago I asked IBM here in
Sydney for some sticks of ram for an old computer. The
nice lady I spoke to said, "Yes we have some 4 MB
ram for four sixty five." I am thinking OK that's good, I'll
have a few of those at $4.65 each. Then she tells me
over 1400 dollars with postage.
"Why do people always scream down the phone
when I tell them the price?" she asked.
Regards,
John Crighton
Sydney
