Leakage from Eico 315 generator
 

Hi gang,
Before I re-invent the wheel, has anyone here solved the low level
signal leakage from an old Eico model 315 signal generator?

Thanks
Bob WB0POQ

Bob Liesenfeld wrote in message ...
Hi gang,
Before I re-invent the wheel, has anyone here solved the low level
signal leakage from an old Eico model 315 signal generator?

Thanks
Bob WB0POQ

=========================
I don't know about the EICO, but most of the "kit" type signal
generators have the same problem. Lots of the leakage is through the
AC line cord. Usually it is bypassed to the chassis, but adding
ferrite beads/sleeves on the AC line inside and outside the cabinet
should help. Commercial signal generators have one of those "canned"
type EMI filters in them, adding one of those should to the trick.
Also, make sure all the cabinet and chassis screws are tight.

Best Regards,

Ed
Canyon Lake, TX

Ed Engelken wrote:

I don't know about the EICO, but most of the "kit" type signal
generators have the same problem. Lots of the leakage is through the
AC line cord.

Hi Ed,
Thanks for the response. I did originally suspect the line cord and added some
filtering but no change.
Interestingly, I have run some tests and most of the RF seems to be spraying off an area
of the aluminum front panel behind which is the frequency setting variable capacitor.
Also, I get some very intriguing nulls in the leakage around the disk screwed to the cap
shaft that has 0-100 calibration markings as a logging scale. I'm suspecting it is acting
as some sort of Faraday screen.......but maybe I've been chasing this problem too long.
Hi hi!

Bob

Interestingly, I have run some tests and most of the RF seems to be spraying
off an area
of the aluminum front panel behind which is the frequency setting variable
capacitor.

The large aluminum dials on many RF generators had phosphor-bronze "fingers"
behind them to keep them well grounded. Also, the paint around the front lip of
the case where the panel is screwed on should be scraped off if it isn't
already. The attenuator assembly should be shielded from where the RF enters it
to the output connector.

RF leakage is one of the big differences between service type generators and
professional equipment. The other is, of course, accuracy of calibration.