[CQ-Contest] Pre tuned Hf amps

peter.voelpel peter.voelpel at t-online.de
Sun Sep 24 23:15:14 EDT 2006

Hi Tim,

We do that as well at DF0CG/DR1A.
One 20KVA supply for amps with 2xQB5/1750, similar to 4-400A but a bit
bigger (500W dissipation). 
Additional at present, loaned modified Henry 3000D decks with their own P/S,
all sitting in a separate amplifier room.
The amps also retuned when there is a change from phone to CW and vice
We constructed similar amps for OTxA, where it happened that they
transmitted without antenna for almost one hour on 80m without recognizing
While listening on their beverages, some qsos where still made, probably
3by3? ;-))

My own amp is with 3 of those tubes and if tuned to our power limitation, it
does not matter to which portion of the band it is tuned and whether
antennas for the band in use are differently adjusted. 

You will see it there:


-----Original Message-----
From: cq-contest-bounces at contesting.com
[mailto:cq-contest-bounces at contesting.com] On Behalf Of Tim Duffy K3LR

USA Multi Multi stations W3LPL and K3LR are using home-brew mono band
amplifiers. LPL uses a single 3-1000Z in each amp and LR uses a single 8877.
These amps are not remote and sit close to the radio. They also need to be
tuned between CW and Phone.

Mono band amplifiers are very easy to build and as long as you have antennas
with similar VSWRs there is no reason to touch the amplifier during the
They work quite well!

You can see pictures of the K3LR amplifiers at http://www.k3lr.com

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