Hello Domenico I8CVS, I did take pictures while I had the cover off :) You can see and download them here:
https://sites.google.com/site/marklhammond/hamradio Indeed, they are labeled "COAXIAL RELAYS" as you suspected. You can also see the "little white button" on the relays that I mentioned previously. 73! Mark N8MH At 02:42 AM 6/2/2011 +0200, i8cvs wrote: >Hi Mark, N8MH and All guys on the list. > >I am very happy that you solved the problem on your preamplifier and since >you took the cover off I would like to know if the relays are or not >"COAXIAL RELAYS" or just non constant impedance relays for AC or DC >applications. > >Can you take a picture on the inside of preamplifier and send it to me by >email ? > >I remember that the owner of Landwehr was a 432 MHz EME'r in the early 1973 >and I worked him off the moon but actually I don't remember his call letter >from Sweden. > >I believe that he dismitted the production of the above preamplifiers many >years ago. > >Tanks > >73" de > >i8CVS Domenico > >----- Original Message ----- >From: "Mark L. Hammond" <[email protected]> >To: "Amsat - BBs" <[email protected]> >Cc: "i8cvs" <[email protected]>; "Vince Fiscus, KB7ADL" ><[email protected]>; "K5OE" <[email protected]> >Sent: Thursday, June 02, 2011 1:44 AM >Subject: Fixed! Re: Landwehr 70cm preamp device question? > > >> Hello All, >> >> You gotta love a happy ending ;) >> >> Thanks to I8CVS, Domenico; Vince, KB7ADL; and Jerry, K5OE for the advice >and coaching with troubleshooting my Landwehr 70 cm preamp. >> >> I took the cover off and applied 12V, and the two relays closed----or did >they?!? >> >> One side looked good, while the other side didn't quite push the "little >white button" enough to make the contacts meet. It was stuck--just a gentle >push with the finger, and I could tell it had become "unstuck." Inserted >back in line, and bingo! It's working just fine. >> >> I have resisted my urges to spray something down in there...figure I can >unstick it the same way another time, should it happen. Looks like the >preamp was made in 1990, based on the dates of the relays. >> >> What I was seeing seemed like it might be a relay issue on one side (could >hear a rise in noise, so the relay at the output side (rig) was working--but >the relay on the input side (antenna) wasn't. So, when powered, the input >relay didn't switch over correctly--what I was seeing now makes sense! >> >> Anyhow, it wasn't the GaAsFET after all. >> >> Thanks again for the help, guys. >> >> 73, >> >> Mark N8MH >> >> >> >>----- Original Message ----- >> >>From: "Mark L. Hammond" <[email protected]> >> >>To: "Amsat - BBs" <[email protected]> >> >>Sent: Tuesday, May 31, 2011 8:00 PM >> >>Subject: [amsat-bb] Landwehr 70cm preamp device question? >> >> >> >>> Hello All, >> >>> >> >>> I have an old Landwehr preamp that apparently uses the MGF1402 device >> >>> (does that sound right?). It's not working so I presume it's the >> >>> GaAsFET. >> >>> >> >>> Can the MGF1302 be substituted for the original MGF1402? Or can >> >>> anybody recommend another device for the 70 cm Landwehr? >> >>> >> >>> I need to do something... >> >>> >> >>> Thanks in advance! >> >>> >> >>> -- >> >>> Mark L. Hammond [N8MH] >> _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
