Where do you find those caps Carl?
Thanks
73
Jim W7RY
----- Original Message -----
From: "Carl" <km1h@jeremy.mv.com>
To: <amps@contesting.com>
Sent: Monday, December 07, 2009 6:37 AM
Subject: Re: [Amps] TITAN II tuning and loading padder capacitors
>
> ----- Original Message -----
> From: "Bill, W6WRT" <dezrat1242@yahoo.com>
> To: <amps@contesting.com>
> Sent: Monday, December 07, 2009 12:54 AM
> Subject: Re: [Amps] TITAN II tuning and loading padder capacitors
>
>
>> ORIGINAL MESSAGE:
>>
>> On Sun, 6 Dec 2009 14:30:38 -0500, "David J Windisch"
>> <davidjw@cinci.rr.com>
>> wrote:
>>
>>>Are these N750 capacitors suitable as padders in this r-f application?
>>
>> REPLY:
>>
>> A lot of manufacturers use N750 or similar caps and they do drift. If the
>> drift
>> isn't excessive, I'd ignore it. Does the power output actually change or
>> are you
>> seeing just the plate and grid readings changing?
>>
>> If you want to fix it , try finding either some NP0 ceramic or
>> transmitting-rated mica capacitors. They are hard to find with high
>> enough
>> current ratings for legal limit amps, and they are expensive if bought
>> new.
>> Don't be tempted to use the little ones the size of postage stamps unless
>> you
>> parallel a bunch of them to spread the heat dissipation.
>>
>> 73, Bill W6WRT
>
>
> Be careful with any mica cap as the older ones are prone to leakage. I
> wouldnt use any without a leakage test of least at 500-600V.
>
> The 12KV teflon disc caps are in wide use these days and seem quite stable
> even at 2500W.
>
> Carl
> KM1H
>
>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|