[Amps] stuff forsale!

[David Robbins]

They 'might' be ok on 160m, there are no big rtty contests on that band so
haven't actually tested one there.  The problem with 40m and 80m is due to
the shorted turns on the toroid creating lots of heat which eventually melts
down the plastic support.  I went through several of them before I modified
one for 80m single band and this one forsale for 40-10m.  For the 80m single
band one  I removed the network for the high bands and put a larger toroid
on top of the rf deck.  For the 40-10m mod I replaced the 3 band toroid with
one that has only turns for 40m on it and also opened up the tiny air holes
a bit more.  As an added advantage they tune much nicer and run cooler than
the originals since the toroid isn't wasting all that rf making itself hot!

David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
web: http://wiki.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://k1ttt.net:7373



-----Original Message-----
From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Bill Turner
Sent: Sunday, October 14, 2018 22:46
To: Amps group
Subject: Re: [Amps] stuff forsale!

------------ ORIGINAL MESSAGE ------------(may be snipped)

On Sat, 13 Oct 2018 00:32:46 -0000, you wrote:

>Commander HF-2500 amp s/n 443 = $1200 plus shipping
>                All band
>                this vintage does NOT have grid protection
>
>Commander HF-2500 amp s/n 698 = $1200 plus shipping
>                modified to do 40-10m only
>                modification will handle RTTY contests on 40m
>                this vintage DOES have grid protection
>                will include damaged toroid you could refurb for all 
>band

REPLY:

Beware of the HF-2500 in its original UNMODIFIED state. The toroid in the
output tank WILL NOT handle full RTTY power on 160-40 meters, as I learned
twice.  I suggest you ask the seller what the modification was which enables
it to do so. Otherwise, you will need ventilation fans in the shack.  :-)

Because of this vulnerability, the manufacturer came out with the Magnum
version, which is preferable if you can find one.  They are rare. 

73, Bill W6WRT
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