Roger, that's because you have a very well-designed amp that behaves itself
and responds benignly with whatever's thrown at it.... :-)
Leigh
VK5KLT
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of Roger (K8RI)
Sent: Friday, 27 July 2012 11:59 PM
To: amps@contesting.com
Subject: Re: [Amps] Overdrive protection
On 7/27/2012 10:11 AM, Jim Hargrave wrote:
> Duh...
> Why not just use the RF PWR adjustment on the front of the transceiver and
> save all that costs and wasted heat dissipated by the attenuator.
>
That is the problem. With the power turned down, the first dit comes
through at full power on some rigs. This approach works just fine in
both of my rigs.
Although the 756 Pro line is notorious for this, mine does not do it,
nor does my FTDX5000MP.
As to ALC I do not use it. The amp has its own internal ALC so the
tiniest amount of grid current will not only shut it down, but requires
a reset and wait for the tube warmup cycle again. It is protected for
about any thing I can think of.
Other than during a tune-up I've never had it kick out.
73
Roger (K8RI)
> "Discipline" is the keyword. With proper drive power management, most
> linears will operate trouble free for decades.
>
> I have a Clipperton-L (1980) with the original tubes. I also have a
> homebrewed 4-400(2) that I built in 1979. I did not even bother to include
> an ALC circuit. Both have been trouble free.
>
> 73s de Jim
> W5IFP
>
> > -----Original Message-----
> > From: amps-bounces@contesting.com
[mailto:amps-bounces@contesting.com]On
> > Behalf Of Michael Tope
> > Sent: Friday, July 27, 2012 8:37 AM
> > To: amps@contesting.com
> > Subject: Re: [Amps] Overdrive protection
> >
> >
> > On 7/27/2012 6:13 AM, Michael Tope wrote:
> >
> > With an extra SO-239 on the rear panel and a coax jumper, the amp
> > manufacturer could provide a "loop-thru" for an external power
> > attenuator. This would allow the user
> > to tailor the drive requirements of the amplifier to their
> > transceiver output characteristics by selecting the appropriate
> > attenuator value.
> > >
> > > 73, Mike W4EF.....................
> > >
> > Oh, duh, I should have said two extra SO-239s, otherwise you couldn't
> > insert the attenuator after the input T/R relay.
> >
> > Mike W4EF.................
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