K3: RE: OT Expert 1k Amplifier

[Enno, PF5X]

I have an Expert 1K-FA for almost a year now. It is relatively expensive,
but still, I would make
the same decision if I had to choose again. Why?
 
1. Very flexible in/output switching => you can run with two exciters and 4
different antennas
2. HF + 6m coverage (but so has the ACOM1000 and a few others)
3. Instant full power out after switching it on. The 2.5 min warm-up time is
simply unacceptable for serious DXing on 6m.
    By the time the amp switches on, the opening has switched off. Thank you
ceramic tube for loosing a valuable new one !
4. Very flexible interfacing for band switching covering all the big TRX
brands, a generic option (covering Elecraft) and HF sensed bandswitching
5. Good protection circuitry + build-in semi-auto antenna tuner (with option
for manual adjustments).
6. The price of an MRF-150 is about US$60 I think, so if you are unlucky you
need to spend about US$360 for a full set of replacement
   transistors, which is still reasonable.
 
I am very satisfied with it. I mostly run it at half power, because that
puts me above the crowd in most cases already.
If the going gets really tough I am going all the way ...
 
ALC interfacing is recommended with this kind of linear. I have already
asked on this reflector how this should be done with the K3. The K3 delivers
a positive
ALC voltage whereas the linear - like other types - needs a negative
voltage. Wayne had replied that this needs a little external circuitry
which will be described in due time. (Looking to the schematics I believe
the K3 does not carry any negative voltage line at all).
 
Before buying a linear (whatever brand or power class), improve your antenna
system first to the best possible, given your local situation !
 
Enno, PF5X
K3, S/N ? (ordered for beginning July 2008 delivery)
 

No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.503 / Virus Database: 269.16.4/1145 - Release Date: 22-Nov-2007
11:49
 
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Doug Faunt N6TQS [phone]]

   From: "Enno J. Korma, PF5X" <[hidden email]>
   Date: Thu, 22 Nov 2007 20:40:30 -0000

   ALC interfacing is recommended with this kind of linear. I have already
   asked on this reflector how this should be done with the K3. The K3 delivers
   a positive
   ALC voltage whereas the linear - like other types - needs a negative
   voltage. Wayne had replied that this needs a little external circuitry
   which will be described in due time. (Looking to the schematics I believe
   the K3 does not carry any negative voltage line at all).

Take a look at the io board- there's a negative voltage generator
there that drives the RS232 level converter.  Page 9 of the
downloadable schematics, KIO3 Main, sheet 2.  

It's not really our Elecraft until we've modified it ourselves.

73, doug
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Enno, PF5X]

OK, that may come in handy.

Made a stupid mistake in my ALC comments though. It is the linear which
generates the negative ALC voltage (0 ~ -5V) and not the other way around as
I described. The K3 is set-up to receive a positive ALC voltage, which need
some external circuitry to adapt for a neg. ALC.

Oh, and do not panic about my stated delivery time. It is on MY request and
not because Elecraft cannot deliver earlier.

 
Regards,
 
Enno Korma, PF5X
 
-----Original Message-----
From: Doug Faunt N6TQS [phone]
Subject: Re: [Elecraft] K3: RE: OT Expert 1k Amplifier

   From: "Enno J. Korma, PF5X"
   Date: Thu, 22 Nov 2007 20:40:30 -0000

   ALC interfacing is recommended with this kind of linear. I have already
   asked on this reflector how this should be done with the K3. The K3
delivers
   a positive
   ALC voltage whereas the linear - like other types - needs a negative
   voltage. Wayne had replied that this needs a little external circuitry
   which will be described in due time. (Looking to the schematics I believe
   the K3 does not carry any negative voltage line at all).

Take a look at the io board- there's a negative voltage generator there that
drives the RS232 level converter.  Page 9 of the downloadable schematics,
KIO3 Main, sheet 2.  

It's not really our Elecraft until we've modified it ourselves.

73, doug

No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.503 / Virus Database: 269.16.4/1145 - Release Date: 22-Nov-2007
11:49
 

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com