[Amps] Overdrive protection

[Vic K2VCO]

In some cases it depends on how you adjust the transceiver.

The TS930s had both a Carrier control and a Power control active in CW mode. The power 
control set the point at which the ALC would hold the output. So if you turned the carrier 
control all the way up and adjusted the output with the power control, you would get some 
overshoot. But if you controlled the output with the carrier control and then left the 
power control set no lower than the point that ALC just started to operate, there was no 
overshoot.

On 7/27/2012 7:32 AM, Joe Subich, W4TV wrote:
>
>> 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.................


-- 
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/