[amsat-bb] L band gear

Thu May 14 12:34:53 UTC 2020

Ed,

Just curious if you have looked at the DEMI L band TX upconverter.  This
was designed for the L band satellite uplink and is a transmit only
converter.  The IF can be 28 MHZ, 50MHz or144MHz.  What I like about the
idea is there is a verion design to be mounted at the antenna which gets
around the feedline loss issue at 1267 MHz.  Still looking at it - as
anyone purchased one?

John

On Thu, May 14, 2020 at 8:28 AM Ed Krome via AMSAT-BB <amsat-bb at amsat.org>
wrote:

> Hi Zack
> My comment about how much easier it is to get to 23cm today was based on
> W1GHZ’s transverter. Great little device. I have been meaning to try mine
> on 1267. Also have thought about using my DigiLO as the LO, since it goes
> to 6ghz. It was slated for a 10ghz transverter but I don’t think it cares.
> You and I should compare notes more often! W1GHZ also has some multiplier
> boards that would simplify use of a lower freq as a base. Not (yet)
> familiar with the Arduino based Si synthesizer. Need to look for that
> thing. Do you have a link? Oh great, a new project to grab my interest and
> devour limited (time) resources. 😁
> The amplifier I referenced was my article. Easy to build, works great and
> 30 watts.
> OK, so I’ll dig out and sweep/tweak the W1GHZ transverter and see what
> happens. Stay tuned.
>
> Ed Krome K9EK
>
> Sent from my iPhone
>
> > On May 14, 2020, at 12:00 AM, Leffke, Zachary via AMSAT-BB <
> amsat-bb at amsat.org> wrote:
> >
> > 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
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> > _______________________________________________
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> > Not an AMSAT-NA member? Join now to support the amateur satellite
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> _______________________________________________
> 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
>