Basically it was done as per wb2wik's posted note.
The EB104 4xMRF150 was built as per moto app note and the CCI sheets, with
their copper spreader. This was then mounted on a big heatsink with 2 24V
blowers at each end. A metal box was then created over the amp. I
incorporated overtemp shutdown, high vswr shutdown and eventually overdrive
shutdown (to protect against not setting the Ft1000MP to 10W o/p and hitting
it with 100W)
There is a dunestar multi band BPF on the input (you will need it anyway to
protect the rx in a multi tx environment). Externally on the output i use
either a homemade 10MHz 1kW LPF when operating LF or a commercial 35MHz LPF
when on the upperbands. The measured output spectrum exceeds FCC
requirements.
This amp hs now been superceded by one based on MOTO APP AR347 using
2xMRF154A. The advantage of this design is that it is slightly more QRO
(capable of 800W) and that it also covers 50MHz, which the EB104 doesnt
Dave
G4FRE
--__--__--
Message: 4
From: "Alan Ibbetson" <g3xaq@hotmail.com>
To: amps@contesting.com
Subject: RE: [Amps] How light can you make a 500W amplifier?
To: <amps@contesting.com>
Date: Tue, 15 Oct 2002 23:58:38 +0100
Dave/G4FRE ( robinda@nortelnetworks.com ) in a private email outlined his
successful use of MOSFETs
>I now use the motorola 2 x mrf154 amp for expeditions capable of 800W
>2-50MHz, the main weight of which is the >copper spreader/heatsink. I used
>to use the 4 x mrf150 but that got retired as it did not cover 6m
Please Dave: I think it would be of general interest to hear the details of
how the EB104 application note was turned into a fully functioning multiband
amp.
Thanks to everyone who took the trouble to follow up to my original posting.
73,
--__--__--
Message: 17
From: Steve Katz <stevek@jmr.com>
To: "'Frank Mayer'" <domino@worldlynx.net>, Amps@contesting.com
Subject: RE: [Amps] Solid State
To: <amps@contesting.com>
Date: Wed, 16 Oct 2002 07:43:07 -0700
That surely depends on the amplifier, but I've used the "CCI" packaged,
Motorola ap-notes based solid-state amps many times and cleaned them up with
Dunestar relay-switched BP filter networks. Using the outboard bandswitched
filter array, the CCI amps clean up very nicely and seem to meet FCC purity
requirements. -WB2WIK/6
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