Paul,
I agree, though I didn't notice that earlier.
73
Don
N8DE
Quoting Paul Decker <kg7hf@comcast.net>:
I admit, I don't know anything about the SB-230, but 100W drive
seems excessive for an 8875/8874, is there some sort of attenuation
for the input?
My 432 MHz amp using a single 8874 tube takes 25 drive to produce 500W out.
Paul,
KG7HF
Date: Tue, 19 Mar 2013 00:55:42 -0700 (PDT)
From: K4MT
To: "amps@contesting.com"
Subject: [Amps] SB-230 Power Question
Message-ID:
<1363679742.11720.YahooMailNeo@web120205.mail.ne1.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1
I recently acquired a SB-230 thinking the tube was probably bad with
an idea of doing a GI7B project. To my surprise the amp puts out
650 watts plus on my peak reading wattmeter on SSB 80/40 Meters
with 100 W drive..
On the bands from 20 and up the power output drops. ?20 Meters is
about 550, 15 meters about 350-400 and I ?have not tried 10m. ?
I recapped PS, rebuilt tube grid circuit and repaired some bad
soldering and out of tolerance parts, replaced grid bypass
capacitors, removed entire tank circuit and band switch. Cleaned
bandswitch and cleaned/resoldered all connections.
Still power on higher bands drop as above.
Any experts on this amp out there who might have an idea what might
be going on. Is this a sign of a weak tube? ?Since I get so much
power output on 80/40M I would think the tube must still have some
life in it.
_______________________________________________
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
|