[Amps] Overdrive protection

[Joe Subich, W4TV]

> 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.

Because many transceivers designers - particularly Icom - control Power
with the ALC circuit.  That does nothing to stop the spike due to a
slow ALC attack time and excess IF gain (excess drive to the PA).

73,

    ... Joe, W4TV


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.
>
> "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 at contesting.com [mailto:amps-bounces at contesting.com]On
>    > Behalf Of Michael Tope
>    > Sent: Friday, July 27, 2012 8:37 AM
>    > To: amps at 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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