[amsat-bb] L band gear

[Leffke, Zachary]

In line with Ed's thoughts on homebrew....

somewhere on my todo list is to take a look at the W1GHZ 1296 transverter kit (SUPER cheap to get on the air, great documentation) with an eye towards 'tweaks' for 1267(ish).  Very high(hi) level ideas include different LO (I think, but haven't confirmed, the digiLO may have an output suitable for this) to produce a useable IF.  I also just discovered the Si5351 arduino controllable synthesizer (~$10 for a breakout board), which with a few multiplication stages and some filtering, might make for a suitable base chip for a configurable custom LO design on the cheap (there's probably already a QEX article somewhere for this).  The builtin PCB hairpin filters on the 1296 transverter might be an issue....but also might not be an issue, and maybe also 'tweakable' (razorblade style....or maybe with a little copper foil tape).

W6PQL has some good reference designs as well for the RA18H1213G Ed mentioned (he might also be the author of the referenced articles, not sure haven't checked).

Wanted to get the basic idea out there in support of the homebrew concept:  W1GHZ transverters for satellite bands.....the idea might be extendable to higher bands as well for future birds (i.e. GOLF) for cheap access to microwave for satellite....the pipecap filters used on higher frequencies are probably more easily tuneable than the PCB filters on the lower bands...so in a way, the higher bands might be easier to tweak for the satellite sub bands.

As is probably obvious, not fully thought through idea, so not sure of the feasibility, and currently pretty far down on the todo list.....but I'd be happy for someone to beat me to the punch!  Adventures in this area would make for some great articles for the Journal and help spread the word and stimulate some microwave activity.

-Zach, KJ4QLP
-- 
Research Associate
Aerospace & Ocean Systems Lab
Ted & Karyn Hume Center for National Security & Technology
Virginia Polytechnic Institute & State University
Work Phone: 540-231-4174
Cell Phone: 540-808-6305


-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces at amsat.org> On Behalf Of Ed Krome via AMSAT-BB
Sent: Wednesday, May 13, 2020 10:22 PM
To: 73 Bob W7LRD <w7lrd at comcast.net>
Cc: amsat-bb <amsat-bb at amsat.org>
Subject: Re: [amsat-bb] L band gear

I’m a bit surprised that so few are using portable (and no homebrew) 1267. Here’s an alternative, homebrew style. Something old and something new. 
Antenna: 12el hb yagi with folded dipole DE, mounted on top of Arrow with 8” fiberglass rod spacers
Amplifier: hb brick amp with RA18H1213G. See AMSAT Journal Jan-Feb 2019 for construction details. Can do 30W, but never use that much. 
Transmit-converter: ancient hb, dbm + discreet transistor amps. Would be so much easier today with MMIC’s. ~1/2W out. Originally built for AO-10 and used  a lot on -10 & -13
RF (2M) source: Baofeng UV5R+ ht. Why? Because that thing has no problem transmitting slightly below the 2M band edge. The trans-converter was crystaled so 145 in = 1269 out. AO92 is 1267.x, so the trans-conv requires 143.x input. In the AO10&13 days, the driver was a Drake T4X driving an hb 2M transverter. Complicated, but as a fixed station (100+W out from 2x7289) it worked well. 
The whole portable rig runs on a single drone battery. 
Now if I could just get around to operating once in a while. 

Ed K9EK

Sent from my iPhone

> On May 13, 2020, at 12:53 PM, 73 Bob W7LRD via AMSAT-BB <amsat-bb at amsat.org> wrote:
> 
> Hi all-  I would be curious to know what "everyone" is using for L band gear.  Perhaps others would like to know.  example I run
> IC-910- at 10W
> 70 feet of LMR600
> 24 element looper yagi horizontal polarized
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions expressed
> are solely those of the author, and do not reflect the official views of AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb

_______________________________________________
Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
to all interested persons worldwide without requiring membership. Opinions expressed
are solely those of the author, and do not reflect the official views of AMSAT-NA.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb