On the subject of Amplifiers

[dw-4]

The recent thread on a possible new Elecraft Amp has made me ponder
about TR switching circuits to an external amp from the 10-watt K2.

I'm guessing that for QSK operation, one has to have a TR relay with a
fast transition speed.  And on top of that, the relay contact ratings
would have to handle the expected output wattage.

I've never used an external amp....are they all GROUND triggered for TR
switching?

Thanks
N1BBR

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[Cookie]

Most are ground triggered, but not all.  Check before you buy!  I am having good results from an AD5X QSK kit on my Dentron Clipperton L that puts out about 600 watts.  I am not sure that it would switch a more powerful amp, but if you are now at 10 watts, you will probably find a 600 watt or less amplifier sufficient.  However, 10 watts is not enough drive for most amps, so check the drive required before you buy.  I get about 30 or 40 watts out of the 4-572Bs on 10 meters with 10 watts of drive.  Many amps will require less drive than the Clipperton L, so check.
 Willis 'Cookie' Cooke
K5EWJ




________________________________
From: dw <[hidden email]>
To: Elecraft_List <[hidden email]>
Sent: Wed, February 17, 2010 8:00:31 AM
Subject: [Elecraft] On the subject of Amplifiers

The recent thread on a possible new Elecraft Amp has made me ponder
about TR switching circuits to an external amp from the 10-watt K2.

I'm guessing that for QSK operation, one has to have a TR relay with a
fast transition speed.  And on top of that, the relay contact ratings
would have to handle the expected output wattage.

I've never used an external amp....are they all GROUND triggered for TR
switching?

Thanks
N1BBR

--
[hidden email]

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[dw-4]

Hi Willis,
I looked at AD5X's web-page and I see he is using a pair of SPDT relays.
One of the cool aspects of that design is the incorporated AMP bias
switching.

I wonder how much switching noise the relays make?

I've seen a few articles on the use of reed relays for switching the AMP
in/out of the signal path.
But the caution there is making sure you get relays that have separate
contacts to avoid possible contact bridging.

I believe the Centurion utilizes one single SPDT relay also.

Interesting stuff!!  :~]
N1BBR


Subject: Re: On the subject of Amplifiers

Most are ground triggered, but not all.? Check before you buy!? I
am?having good results from an AD5X?QSK kit on my Dentron Clipperton L
that puts out about 600 watts.? I am not sure that it would switch a
more powerful amp, but if you are now at 10 watts, you will probably
find a 600 watt or less amplifier sufficient.? However, 10 watts is not
enough drive for most amps, so check the drive required before you buy.?
I get about 30 or 40 watts out of the 4-572Bs on 10 meters with 10 watts
of drive.? Many amps will require less drive than the Clipperton L, so
check.
?Willis 'Cookie' Cooke
K5EWJ
--
 [hidden email]

______________________________________________________________
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Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html