[Amps] Multiple Amplifier Switching Box

[Dave Hachadorian]

I have run an AL-1500 and SB-220 in series.  Absolutely do not do 
this if the second amp in line is equipped with QSK circuitry, 
because RFI from the high level of other-band power may switch 
its relay into transmit.  As N2BC says, at that point the second 
amp is toast.

I have a Ten-Tec Titan 417A that will switch into transmit just 
from 20 meter energy coming back down its coax from the antenna. 
For example, while the AL-1500 is transmitting on 20, I'll look 
over and see idling current on the 417A, because it has switched 
itself into transmit.  I don't  use QSK on either amp.  I had to 
put a 20 meter reject stub on the 417A to keep it from doing that 
evil behavior.  Maybe if you flip the manual standby switch into 
standby, it won't happen, but you can't be fiddling with that all 
the time, and you only have to forget once - then you're cooked.


Dave Hachadorian, K6LL
Big Bear Lake, California




-----Original Message----- 
From: Michael Clarson
Sent: Thursday, August 23, 2012 9:23 AM
To: n2bc at stny.rr.com
Cc: amps at contesting.com
Subject: Re: [Amps] Multiple Amplifier Switching Box

N2BC: Not sure I understand why QSK would be an issue -- if your 
amp is in
Standby, you should be able to run exciter through it, correct? 
You do have
a point -- one needs to make sure IF series amps are tried, that 
the bypass
around the amp can handle another amps full power and not just 
exciter
power levels. --Mike, WV2ZOW

On Thu, Aug 23, 2012 at 11:40 AM, N2BC <n2bc at stny.rr.com> wrote:

> Amps in series....  not so good.    I would guess that most QSK 
> amps have a
> form of RF 'sniffer' on the input to prevent hot switching.
>
> Following a massive brain cramp, I cabled a KWS-1 (600W) 
> through a TenTec
> Titan.  Was a bit confused when smoke started to curl out of 
> the Titan & it
> was powered off.   Result: charcoal grid circuit.
>
> -----Original Message-----
>
>  Tessco ( www.tessco.com ) sells RG-400/U in one foot 
> increments. If your
> > amps have built in antenna relays, have you considered 
> > hooking your
> > amps in series and just switching the PTT line? --
>
>
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