Not so long ago some expert on here said I was optimistic about my erp and
divide by 2. I have been worried ever since !!!!!!!!!!!
g3kev
----- Original Message -----
From: "James Moritz" <james.moritz@btopenworld.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Thursday, September 29, 2011 6:06 PM
Subject: Re: LF: Wilkinson combiner
> Dear Mal, Scott, LF Group,
>
> The Decca design does not only use a combining transformer (effectively
> connecting the 3 PA module outputs in parallel). Each PA module has a
"guard
> circuit" RF current limiter that protects the individual PA in the event
of
> a low-impedance antenna fault, or a fault in one of the other PAs. The
Decca
> design concept provides a measure of redundancy - if one PA fails, a new
> module can be "hot swapped" while the other two continue to produce some
> output. This isn't really needed for an amateur radio TX - with the bigger
> SMPS MOSFETs available today, it is easier and cheaper to design and build
a
> single large PA.
>
> But with a large antenna as you often describe, a high power PA really
> shouldn't be necessary - 100 - 200W should be plenty to reach 1W ERP. If
it
> really takes so much power, perhaps you really need to investigate why
your
> antenna efficiency is so dismal before running up your electricity bill!
>
> Cheers, Jim Moritz
> 73 de M0BMU
>
>
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