...seems like too much of a good thing to me!
If you consider that most of the amplifiers in use are of the grounded grid
variety, with the attendant low input impedance, the Q of the tune network
at the input is not outstanding. As such, I consider installing such a
complex unit an overkill. The only practical advantage that might be gained
would be a less complicated band switching arrangement. Some band limited,
higher Q, true lowpass network would be a better choice at the input of the
amplifier. It's a set and forget arrangement, in any case.
73 and all the best:
Alex 4Z5KS
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of k7rdx
Sent: Thursday, February 12, 2009 6:46 AM
To: kc0hfl@cox.net; Amps@contesting.com
Subject: Re: [Amps] Autotuners in Amps
I have used the LDG board in my 3CPX5000A7/YC-156A amplifier since 2006 with
excellent results:www.k7rdx.w4zt.com. The tuner is an L network so adding c
at the cathode is a good idea for better harmonic rejection..Tune-up is
easy, just apply a few watts rf drive for a few seconds to initialize the
microprocessor and the tuner matches the exciter to cathode with very low
SWR.I recommend mounting the auto tune board in an rf proof compartment with
the interconnect no more than six or seven inches from the tube cathode. I`m
sure LDG didn`t sell enough units to make keeping them on the market a
profitable venture..Jim..K7RDX..
----- Original Message -----
From: <kc0hfl@cox.net>
To: <Amps@contesting.com>
Sent: Wednesday, February 11, 2009 7:25 PM
Subject: [Amps] Autotuners in Amps
>I seen the new handbook had an amp project using an LDG auto tuner for the
>tuned input and was curious what the groups thoughts was on this. After
>some research I came across an add where LDG actually marketed a tuner for
>this but has been discontinued. Seems like a good idea or is it?
>
> 73, Bob kc0hfl
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
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