On Fri, 27 Mar 1998 15:34:40 -0000 "Geurts, Gerard" <email@example.com>
>> I didn't think we could find a subject with so much agreement
>> This suggests the inputs are technically correct................
>> I have this nasty idea that I'm going to have to build a GDO.
>> BUT is it possible to test using a resistor plate to ground (of
>> resistance as the plate wants to see), no DC, a VTVM with a good RF
>> probe at
>> the plate and feed in at say 5 watts from the antenna end and check
>> that the
>> volts at the plate are correct when tuned up? Do it on all bands of
>> Not as easy as dipping the RFC with a gdo, but easier than building
>> GDO to
>> do the job.
>> Peter G3RZP
>Or test using a resistor plate to ground, no DC, RFC not connected or
>maybe even not present. Measure return loss at antenna port, tune
>circuit for desired frequency, connect RFC. The only thing you should
>see is a change in the tune capacitor setting, especially at the lower
>bands. Could be done with an antenna analyser, TX and SWR meter or
>that is by far the easiest way to do it) with a Network Analyser.
>fine for me.
>Gerard, MoAIU / AA3ES
All good info Gerard and Peter. See, there are alternatives BUT a GDO is
such a useful device for anyone working around RF...without the benefit
of an HP equipped lab...should have one.
Peter, the last time I checked, CIRKIT on ur turf was still selling a
fine GDO kit.
On this side of the pond GDO's are showing up quite regularly as older
hams die off and new ones cant figure out how to attach a PL-259.
Check the various Internet swap groups, HF swap nets and flea markets.
For amp use even the old Heath and Eico types are more than adequate. I
use a 1950's era Measurement Corp Model 59 ( still has the National Radio
ID tag) and the one I built in 1956 from a 1949 CQ article works just as
73 Carl KM1H
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