I like the switch used in the Johnson Thunderbolt II aka Tempo 2000.
The fiberglass plate was attached to the end of the large coil and populated
with heavy duty contacts and wiper (similar to B&W tank coil)and with real
long arc paths. It was not a shorting switch. The fiberglass shaft went
thru the center of the coil as did the copper strap connections. The one I
worked on last year was a one owner and had seen a long, heavily used, and
trouble free life until the PS let loose.
Carl
KM1H
----- Original Message -----
From: <TexasRF@aol.com>
To: <paul@n1bug.com>
Cc: <amps@contesting.com>
Sent: Wednesday, November 17, 2010 9:38 AM
Subject: Re: [Amps] 2010 Handbook
> Now that band switching scheme shows some real innovation! I bet it never
> arced did it?
>
> I once built an amplifier that used a plexiglas disc/cam that pushed on
> scavenged relay leaf/contacts in a similar manner, one cam per contact.
> Ugly
> but worked well. Allowed switching cap A, cap B, cap A+B and so on. Your
> screw driven switches would do that also of coarse.
>
> 73,
> Gerald K5GW
>
>
>
>
>
> In a message dated 11/17/2010 7:35:42 A.M. Central Standard Time,
> paul@n1bug.com writes:
>
> That's true Gerald. :-)
>
> The 1/2 inch wide brass "U" clips on the grid, cathode, and filament
> were quick enough, but the 6 screws for the clamp plates to hold the
> tube in place (by means of clamping its screen to the chassis) took
> most of the time!
>
> Band switching could take almost as long, with lots of little knobs
> which drove screws, which pushed flexible fingers of aluminum (!)
> against contacts on the tune and load padder capacitors, thereby
> grounding one side of them. This in various combinations was
> required on 40, 80, and 160 due to the way-too-small air variables used.
>
> Those were the days! Uh..... or not!
>
> 73,
> Paul
>
>
> TexasRF@aol.com wrote:
>> Well Paul, if you used alligator clips for the tube connections you
>> could change the tube in half the time!
>>
>> 73,
>> Gerald K5GW
>>
>>
>> In a message dated 11/17/2010 5:19:00 A.M. Central Standard Time,
>> paul@n1bug.com writes:
>>
>> Roger (sub1) wrote:
>> >> 4CX1000A?
>> >
>> > 4. It uses an oddball socket
>>
>> I once built a successful 160-10m amp around a 4CX1000A with no
>> socket at all. OK, it took 10 minutes to change out the tube, but
>> you rarely if ever have to replace one.
>>
>> > Maximum frequency for full power is only 110 MHz, but I
>> believe
>> > it will operate at 144-147 MHz at reduced ratings and a pair in
>> PP will
>> > easily run more than the legal limit.
>>
>> I ran a single 4CX1000A at legal limit on 144 MHz for years, never
>> had any issue at all with it. These tubes have also been used at 222
>> MHz, though one doesn't see that too often.
>>
>> 73
>> --
>> Paul, N1BUG
>> Aurora Sentry: http://www.aurorasentry.com
>> Piscataquis ARC: http://www.k1pq.org
>> N1BUG: http://www.n1bug.com
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>
> --
> Paul, N1BUG
> Aurora Sentry: http://www.aurorasentry.com
> Piscataquis ARC: http://www.k1pq.org
> N1BUG: http://www.n1bug.com
>
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