Hello:
I have a high power attenuator that could be inserted beetween the
transceiver and amp input to minimize variations in amp input impedance. If
there are any? I think we can forget the loading impedance variations of
grid current across a 50 ohm or less. This attenuator is oilfilled, good for
400 watts under a short period of time and avaiable from me free no charge
under a test period of the DAF.
As for standard testing procedure, why not modulate the rig with one of the
music standards found on CDs all over the world? So, just any ham can
reproduce the test? You let the spectrum analyzer memorize ( freeze )
everything that happens under, say, one minute and read after that the
maximum distorsion that occured. You must do this with different ALC
readings on the transceiver. Use a TS 950 that has very low pa intermod.
For years DL1BU with his commercial lab and testing knowledge tested in the
German CQ-DL many amateur gear including antennas. One test that was very
good and not done nowadays is, that he made several pa linear tests with
different ALC readings on the meter - one also just a the start of the ALC.
He got often very different results.
Now back for the Timor hunt on 21200.
Sooner................. de Hans SM5KI
----------
>Från: Peter Chadwick <Peter_Chadwick@mitel.com>
>Till: amps@contesting.com, "'Steve Thompson'" <rfamps@ic24.net>
>Ämne: RE: [AMPS] test signals
>Datum: tor 30 mar 2000 07.54
>
>
>Steve says:
>
> >The only problem will be finding a radio that's good enough to
>deliver a
> >clean drive signal.
>
>I don't think that's the only problem. There is also interpretation of
>results. At the end of the day, the results will indicate either:
>
>1. The principle is capable of producing a clean signal
>
>2. The principle as embodied in the test amplifier is not capable of
>producing a clean signal.
>
>If case 1 is the result, that's all it proves - not that all G2DAF type
>amplifier implementations produce clean signals.
>
>If case 2 results, it still doesn't mean that it is impossible to produce a
>clean signal under some conditions. If case 2 results from tests on the
>original G2DAF (assuming that the original tubes are still good), then it
>definitely throws doubts, but doesn't prove that the principle can never
>work under any circumstances.
>
>
>Incidentally, in view of the grid current loading, I would suggest that
>either a tubed exciter with a tuned output network, or some form of input
>tuned circuit be put in the line between exciter and amplifier be used to
>minimise difficulties with load change caused by grid current. Preferably
>the former, since the intention is to reproduce the original work.
>
>By the way, can anyone get hold of the original UK patent?
>
>73
>
>Peter G3RZP
>
>
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>
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