Re: [TenTec] Corsair II to Collins 30L-1 amp -- any issues?

[Ken Brown <ken.d.brown@verizon.net>]

Hi Adam,

I am going to answer your questions with generalities and let you figure 
out which specifics apply to your gear. You've got a ham license so if 
you have the manuals for the equipment, this should help you understand 
it well enough to figure it out by reading the manuals.

Amplifiers can require anywhere from one to five different 
interconnections to a transceiver as follows:

1) RF drive from the transceiver. Most amplifiers also let the receive 
signal from the antenna bypass the amplifier and go to the transceiver 
during receive. This is done with a single coax cable. It is also 
possible that the switching system could be external to the amplifier.

2) Keying from the transceiver to the amplifier. Usually this is just a 
single cable, typically a shielded cable, could be coax. The transceiver 
provides some kind of keying signal to the amplifier to tell it when to 
switch to transmit mode. There are several ways of doing this, and if 
the transceiver's way is not compatible with the amplifier's way, not 
only will it not work, it could also damage something. It could be 
pulling a low voltage to ground. It could be pulling a higher voltage to 
ground. Or it could be applying a voltage. Some newer transceivers use 
an open collector transistor output to pull a positive low voltage 
supplied by the amplifier to ground when it is time to transmit. Some 
older amplifiers have a high (about 150 Volts) negative voltage that 
needs to be pulled to ground. If you connect this combination together 
it will not work and you will blow out a transistor or perhaps worse. 
Interface circuitry can be  built to make it work. This could be as 
simple as a relay. Some transceivers have relay contacts available for 
this purpose. Also there are some amplifiers that have RF drive sensing 
that automatically key up when RF comes from the transmitter. I do not 
recommend using that kind of setup except for VHF/ UHF FM or CB, and 
frankly I do not recommend any of those things.

3) ALC (automatic level control) Some amplifiers have an output that can 
tell the exciter (transceiver) to reduce drive to prevent overdrive and 
distortion in the amplifer. This is also a single cable, typically a 
sheilded cable, like coax. If you adjust the drive properly you can do 
without this. This is another situation where different equipment may 
use different voltage levels and polarities which may not be compatible. 
Still it is better to get it working especially for SSB operation.

4) Transmitter enable from the amplifier to the transceiver. This is 
ususally only necessry for full QSK operation. This lets the amplifier 
tell the exciter when it is ready for drive power. It helps prevent "hot 
switching" relays. If you're not running full QSK number 2 above is 
probably sufficient. This is also a single cable, typically sheilded, 
like coax.

5) Band switching control. Some amplifiers can be automatically switched 
to the correct band by information from the transceiver. There are 
probably a lot of different systems requiring many different kinds of 
voltage levels, numbers of wires and kinds of connectors.

Have fun learning how to operate an amplifer.

73 DE N6KB


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