The cantenna I was using was a makeshift for testing a 3cpx5000a7 homebrewed
amp I had constructed. I used 3 gallons of veggie oil in a plastic storage
container. I drown nine, 18" long carborundum resistors in the oil and
covered the container with a thick aluminum plate. I could only test to 2500
watts output because of the bird 2500 watt element limitation. But, I could
test for a long, long time.
With the dummyload lying on the concrete floor in the garage, I figured
it wouldn't radiate very well. One morning I forgot to switch from the
dummyload to the trapped 40/80 inverted vee and ended up QSOing a friend 200
miles away on 75 mtrs with S9 signal.
The veggie oil works pretty good for a while but tends to
gum up at hot points. This might be remedied by putting some type of
pump/circulator inline. Seems like lots of trouble for a dummy load but the
veggie oil is available locally at about 1/4 the cost of mineral oil. I have
no idea what the flash point is for veggie oil. Could be dangerous.
Larry N5BIP
-----Original Message-----
From: HAROLD B MANDEL [mailto:ka1xo@juno.com]
Sent: Tuesday, February 28, 2006 6:54 AM
To: lncarman@swbell.net
Subject: Re: [Amps] figuring tube output impedance
Hi Larry,
Remember 2 years ago when I was in a hotel in NJ and tried out
one of them tetrode Emtron DX-3's?
I used a Cantenna, too, and it got so hot in a few seconds of tuning
the steam was coming out the escape hole: "TSSSSST!"
Too bad it had a power supply with 18% sag on key down.
Imagine what a great amp it would be if the designers didn't
cut corners on everything?
I'm a-building another amp in my hotel room these days. The outboard
supply is meant to be desktop, but I can't lift it hardly
anymore and the covers and panels aren't even on yet!
I started with an Alpha 76 husk and put in some 3CPX800A7's with
elevated plate voltage and ampacity. The PSU is rated at
2 amperes CCS. BOOM!
Hal
W4HBM
On Mon, 27 Feb 2006 18:44:42 -0600 "Larry Carman" <lncarman@swbell.net>
writes:
>
> With 3900 watts you can fry tasty chicken in the dummy load if you
> use
> vegetable oil. Think the FCC would fall for that one???
> ... I actually had a dummy load filled with vegetable oil. Worked ok
> but oil
> gummed up around the heated metal contact points after a while.
> Regards,
> N5BIP
>
> -----Original Message-----
> From: amps-bounces@contesting.com
> [mailto:amps-bounces@contesting.com] On
> Behalf Of Partain, Chuck
> Sent: Monday, February 27, 2006 2:41 PM
> To: Bill Turner; amps@contesting.com
> Subject: Re: [Amps] figuring tube output impedance
>
> yea they're going to love me.
>
> and I guess with that line of thinking, I should drive home doing
> 145 in the
> 40.
>
>
>
> -----Original Message-----
> From: Bill Turner [mailto:dezrat@copper.net]
> Sent: Monday, February 27, 2006 3:37 PM
> To: Partain, Chuck; amps@contesting.com
> Subject: Re: [Amps] figuring tube output impedance
>
>
> ORIGINAL MESSAGE:
>
> At 10:36 AM 2/27/2006, Partain, Chuck wrote:
>
> >I run 3.9kv and I'm GUESSING 2 amp.
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> I'm GUESSING the FCC will be very interested in your amp.
>
> Even at a lousy 50% efficiency that is 3900 watts output.
>
> Bill, W6WRT
>
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>
> _______________________________________________
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>
>
Harold Mandel
Superintendent of Construction
Baran Telecom Inc.
606 - 205 - 0172
hmandel@barantelecom.com
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