[amsat-bb] Repairs Landwehr preamps ( VHF and UHF )

i8cvs domenico.i8cvs at tin.it
Fri Jun 6 00:02:07 UTC 2014

Hi Alan, WA4SCA and Jim WD0E

I have inspected the VHF and UHF schematic diagrams at


and found that for 435 MHz the input GaAsFET  Q1 is a
widely well know MGF-1402

For 2 meters VHF the input GaAsFET T5 is a N Channel GaAs-Shotky
Gate Tetrode  (for example TEXAS S 3030 ) wich is more difficult to find
BTW the 2SK571 or the 2SK406 should work equally well

see also:


In any case the Manufacturer of Landwehr was in Sweeden starting about
30 years ago and the owner of the Company was a radio ham active on
432 MHz off the moon.

I have contact him on EME several time but actually I don't remember if he
was SM6AKW or SM3CKU and unfortunately both of them do not
appears on QRZ.com

It should be nice to investigate onto the american callbook and sent to both
a letter.

Have fun

Best 73" de i8CVS Domenico

----- Original Message ----- 
From: "Alan" <wa4sca at gmail.com>
To: "'Jim White'" <jim at coloradosatellite.com>; "'AMSAT-BB'"
<amsat-bb at amsat.org>
Sent: Thursday, June 05, 2014 5:58 PM
Subject: Re: [amsat-bb] (no subject)

> Jim,
> Check with Radio Dan:
> http://www.radiodan.com/ted_stuff/landwehr.htm
> The schematics can be downloaded at the bottom of the page.
> 73s,
> Alan
> <-----Original Message-----
> <From: amsat-bb-bounces at amsat.org
> <[mailto:amsat-bb-bounces at amsat.org] On Behalf Of Jim White
> <Sent: Thursday, June 05, 2014 10:22 AM
> <Subject: [amsat-bb] (no subject)
> <
> <I'd appreciate any info on who repairs Landwehr preamps (VHF
> <and UHF).
> <Resurrecting mine from 1990 and they are both dead.  They have what I
> <recall to be the classic symptom of a blown GasFET, when you
> <apply power
> <you get about 30dB of loss.
> <
> <Jim
> <WD0E
> <jim at coloradosatellite.com

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