[amsat-bb] Re: L band amplifier group buy

Mark L. Hammond n8mh at embarqmail.com
Mon Oct 29 04:58:42 PST 2007

Thanks for the comments, Ed.

The unit I purchased from KJ6KO was retuned to 1269; he said it was a slight improvement over stock (1296).

With about 5W in, I get 60W out at 29.7V at full load.  Nice!

The amp is very well made.  Some comments for those interested:

1) He recommends 6W as the MAXIMUM input power (thus running mine at 5W).

2) There is no T/R relay, which for me at the moment is not an issue.  I intend to use the 1.2GHz as an uplink only.  

3) The amp is very hefty (but not all that heavy) and well made.  I am very impressed!  

4) The amp has a bias activiation PTT line that is rated at something like 7 mA at 30V; check his page for specifics.   The TS-2000X literature rates the EXT.CONT (pin 4) 1.2GHz AMP relay at DC 20V, 20mA max.   BE CAREFULL: I am using it at the 30V for now; I think I need a keying circuit!! Don't want to damage the TS-2000X.  (I'll be interested in other people's keying circuits as they put these amps into service.  I built one from an NPN, a PNP, and a few resistors but I'm too chicken to try it out yet :)  )

5)I'm using an ASTRON LS-10A for the 30V supply.  It seems welll suited for the task.   Info here:  http://www.astroncorp.com/w28.shtml 

6) Last night I was able to access the GO-32 BBS with a 1.2GHz uplink--that's a first for me!  I couldn't get into it before with just 10W.

I can put this purchase on the "highly recommended list"!  He was great to deal with. 


Mark L. Hammond [N8MH]

----- Original Message -----
From: "Edward Cole" <kl7uw at acsalaska.net>
To: "Andrew Glasbrenner" <glasbrenner at mindspring.com>, amsat-bb at amsat.org
Cc: "Mark L. Hammond" <n8mh at embarqmail.com>, kj6ko at innercite.com
Sent: Sunday, October 28, 2007 11:28:03 PM (GMT-0500) America/New_York
Subject: Re: [amsat-bb]  L band amplifier group buy

At 12:00 PM 10/28/2007, Andrew Glasbrenner wrote:
>Hi guys,
>I'm sending this from the airport waiting for my flight home from Symposium.
>As I discussed with a few of you here, I have just this weekend arranged a
>discounted price for AMSAT members on what looks to be a real deal on an
>L-band amplifier. I'll let the seller's webpage provide the details, but he
>has indicated that he will sell these amps, tuned for 1269 if so desired,
>for $195 dollars including shipping (lower 48 US). I'm ordering one this
>week, and I believe Mark Hammond N8MH has one already. I'd like to thank
>Mark for turning me on to these, and being the early adopter. Check them out
>We need 5 people to get this pricing, so please drop me a line if you order
>73, Drew KO4MA

Just a note to tell you I bought one of these from KJ6KO about 
3-years ago for 1296.  With 29.5 volts and 10w drive I am seeing 70w 
output.  Since the amplifier is broadband tuned it may work at both 
1296 and 1269.  You probably should contact Greg for his experience 
in converting these amps; he would know how wide a band they perform 
over.  I heartily recommend these amps!

Ed - KL7UW
  BP40IQ   50-MHz - 10-GHz   www.kl7uw.com
144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w
DUBUS Magazine USA Rep dubususa at hotmail.com

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