Hi
I re-measured the RFC resonanse of my ameritron amp (I replaced the RFC
after a previous burnout on 30 meter).
For the new measurement i shortcircuited the choke, while normally mounted
in the amplifier, with a short wire. The wire had a one turn winding, I used
to couple to the dip meter.
The results are:
fo = 19.780 MHz
fo = 11.550 MHz
fo = 23.380 MHz
fo ~ 35.000 MHz
The first set of measurements I did (6/12), I just held the dip meter close
to the RFC. This measurement had dip fo= 27.711 MHz and rised some concern
of safe operation on 10 meter. This dip is gone now, but can I be sure all
is well ?
What is the best methode of measureing the parasitic frequences of a RFC - i
hate to have "dismount" the RFC :=( ?
--
OZ1AXG Flam
----- Original Message -----
From: "OZ1AXG Flam" <oz1axg.nospam@dxmail.dk>
To: "Carl" <km1h@jeremy.mv.com>; <amps@contesting.com>
Sent: Sunday, December 07, 2008 12:06 PM
Subject: Re: [Amps] Plate choke resonanse and safe operation
> the RFC is Installed
>
> I will try to measure the resonans again. For 27 MHZ i did the measurement
> 3
> times. A grid dip meter is not the most accurate instrument, so i will try
> it again. but how close is "safe" ? what would the symptoms be at tuneup
> if
> resonans is close by ?
>
> Then old RFC fried (broke a wire) when i accendential tranmitted 125 watt
> (1/2 second) in the amplifier. Had forgotten to reduce the drive before
> tuning :=( This has happened before on other band - but this was a first
> for 30 meters ...
>
> OZ1AXG Flam
>
> ----- Original Message -----
> From: "Carl" <km1h@jeremy.mv.com>
>
>
>> Is that installed or on the bench? That first one is too close for
>> comfort for 10M CW.
>
>
>
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> http://lists.contesting.com/mailman/listinfo/amps
>
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