[Amps] a common topic here tspa

[John T. M. Lyles]

There are numerous commercial (HF frequency, ISM) 8877/3CX1500A7 
amplifiers on this planel which don't have nor need VHF suppressors 
around the tube. I have one from RF Power (Plasma) Products which I 
converted to 5 MHz from 13.6 MHz a couple of years ago (got advice 
and a schematic from folks on this forum). It is very stable, into 
horrible VSWRs, even sweeping the input drive frequency around while 
testing large ferrite cores under high power. However, maybe the 
correct wording is the only "Ham" HF amplifiers? Because of the need 
to operate multiband, with some sort of shunt feed RF choke, it is 
possible that they require more stringent controls on parasites. 
Fixed frequency ISM power unit manufacturers don't seem concerned 
either.

John
K5PRO

>Date: Mon, 4 Apr 2005 03:23:35 -0700
>From: R.Measures <r at somis.org>
>Subject: Re: [Amps] AL1500
>To: n4xp at juno.com
>Tom -- It has the ability to occasionally oscillate at VHF -- because
>it is the only HF 8877 amplifier on this planet that uses no VHF
>suppressor whatsoever.


>On Apr 3, 2005, at 4:29 PM, n4xp at juno.com wrote:
>
>>  Would those with or having had an AL1500 please provide me insight as
>>  to
>  > its abilities.  Also pros and cons would be appreciated.