On 05/13/20 21:21, Ed Krome via AMSAT-BB wrote:
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.
Ed-
I'm an avid home-brewer, but family, work, grad school, and volunteering has gotten in the way of me getting a real satellite station on the air.
I have a mostly-built 23cm FM rig (http://www.pe1jpd.nl/index.php/23cm_nbfm), which I bought as a first-pass attempt at getting on 23cm. Just needs to be buttoned up into a chassis and we're ready to roll.
I've also duplicated a few preamp designs (https://www.n0zgo.net/lna), and started building a SatNOGS v2 rotator using laser-cut mounting plates (https://www.n0zgo.net/satellite/satnogs/rotator_build).
Some day, I'll get this stuff done and on the air. :-)
I hope more amateurs build their own equipment. So many diagnostic aids (SDR, o-scopes, spectrum analyzers) are available for cheap compared to 20 years ago!
--- Zach N0ZGO
Ed-
I'm an avid home-brewer, but family, work, grad school, and volunteering has gotten in the way of me getting a real satellite station on the air.
I have a mostly-built 23cm FM rig (http://www.pe1jpd.nl/index.php/23cm_nbfm), which I bought as a first-pass attempt at getting on 23cm. Just needs to be buttoned up into a chassis and we're ready to roll.
I've also duplicated a few preamp designs (https://www.n0zgo.net/lna), and started building a SatNOGS v2 rotator using laser-cut mounting plates (https://www.n0zgo.net/satellite/satnogs/rotator_build).
Some day, I'll get this stuff done and on the air. :-)
I hope more amateurs build their own equipment. So many diagnostic aids (SDR, o-scopes, spectrum analyzers) are available for cheap compared to 20 years ago!
--- Zach N0ZGO
Zach, all,
You'll also need an antenna. Surprised that's not been mentioned in this drift into homebrewing...
Before I got my 30 element Beam at a swap meet, I was using a homemade 17 turn Helix. It was easy to make, and worked quite well. I would not say that the beam was any better, especially since the helix is circularly polarized. I still have it, and may swap it back into service some day.
Greg KO6TH
On 05/14/20 13:41, Greg D wrote:
You'll also need an antenna. Surprised that's not been mentioned in this drift into homebrewing...
Before I got my 30 element Beam at a swap meet, I was using a homemade 17 turn Helix. It was easy to make, and worked quite well. I would not say that the beam was any better, especially since the helix is circularly polarized. I still have it, and may swap it back into service some day.
Yep! Plenty of designs out there, should one want to build vs buy:
https://vk1sotaon23cm.wordpress.com/23-cm-antennas/
One of these cheap, perhaps-not-perfect-but-good-enough VNAs would help tune it up:
https://www.tindie.com/products/hcxqsgroup/nanovna-v2/
(I have the v1, which is good up to ~900 MHz, and have been pleased with it.)
--- Zach N0ZGO
Following up on an earlier request from Ed...here is the QEX article on a GPS Disciplined VFO based on the Si5351
https://hamsci.org/sites/default/files/publications/2018_QEX_Downey_GPSDO_Si... (link will download a pdf).
There are a lot of example projects out there in terms of example Arduino code and libraries for controlling the Si5351, particularly if you google 'Si5351 WSPR transmitter'. I saw at least one post about some building a quadrature LO out of one as well (implying some ability to control phase relationship that I don't fully understand yet between the three outputs). 'etherkit' and some of the products on QRP labs (that use the etherkit software) are also useful search terms.
Also the adafruit breakout can be found here: https://www.adafruit.com/product/2045, approx. $8. The etherkit folks also make a breakout board: https://www.etherkit.com/rf-modules/si5351a-breakout-board.html ($10) which is the one used in the above link (though they are pretty interchangeable). The base part is something like $2 on digikey for the custom PCB enthusiasts.
Again, not a drop in replacement for something like the DigiLO (Though I did confirm the digiLO has specific switch settings that would produce Ifs at 2m or 70cm for a 1265-ish RF freq.....there are a couple options). The Si5351 goes up to 160 MHz for starters (not 6 GHz), is a square wave generator and produces lots of harmonics (filters!)........but it is cheap, simple to use, and that first link above shows how to make a pretty cheap, GPS disciplined signal generator.........There are other 'watch outs' about the base crystal frequency when using the higher frequencies....not sure exactly what the issue is, something about step size......but that's the fun of homebrew.....lots of threads to pull.
For the really adventurous that like messing with untested HW and SW, there is this: https://github.com/zleffke/kicad_wspr/tree/master/si5351_featherwing_v1/rev-, I'm attempting to get an Si5351 breakout into featherwing form factor (I like the adafruit feather microcontrollers, and I like that adafruit posts their EagleCAD files on github, making something like this fairly easy to produce). There is also this for more Arduino code related to the Si5351.... https://github.com/zleffke/arduino_wspr ...my attempts at custom Arduino code, obvious from the name, I'm messing with WSPR, but the base code for interfacing with the chip is in there as well as an example (I use the etherkit libraries, unmodified). For the last two links.....USER BEWARE....not sure if I actually know what I'm doing yet or not (though my breadboarded WSPR transmitter based on this chip appears to work just fine). Hihi
Hope this helps! Slight tangent from the core L-Band discussion, but relevant. -Zach, KJ4QLP
Yes, help it does. Now to spend the rest of the day trying to figure some of that magic out... Thnaks! Ed
On May 14, 2020 at 2:57 PM "Leffke, Zachary via AMSAT-BB" amsat-bb@amsat.org wrote:
Following up on an earlier request from Ed...here is the QEX article on a GPS Disciplined VFO based on the Si5351
https://hamsci.org/sites/default/files/publications/2018_QEX_Downey_GPSDO_Si... (link will download a pdf).
There are a lot of example projects out there in terms of example Arduino code and libraries for controlling the Si5351, particularly if you google 'Si5351 WSPR transmitter'. I saw at least one post about some building a quadrature LO out of one as well (implying some ability to control phase relationship that I don't fully understand yet between the three outputs). 'etherkit' and some of the products on QRP labs (that use the etherkit software) are also useful search terms.
Also the adafruit breakout can be found here: https://www.adafruit.com/product/2045, approx. $8. The etherkit folks also make a breakout board: https://www.etherkit.com/rf-modules/si5351a-breakout-board.html ($10) which is the one used in the above link (though they are pretty interchangeable). The base part is something like $2 on digikey for the custom PCB enthusiasts.
Again, not a drop in replacement for something like the DigiLO (Though I did confirm the digiLO has specific switch settings that would produce Ifs at 2m or 70cm for a 1265-ish RF freq.....there are a couple options). The Si5351 goes up to 160 MHz for starters (not 6 GHz), is a square wave generator and produces lots of harmonics (filters!)........but it is cheap, simple to use, and that first link above shows how to make a pretty cheap, GPS disciplined signal generator.........There are other 'watch outs' about the base crystal frequency when using the higher frequencies....not sure exactly what the issue is, something about step size......but that's the fun of homebrew.....lots of threads to pull.
For the really adventurous that like messing with untested HW and SW, there is this: https://github.com/zleffke/kicad_wspr/tree/master/si5351_featherwing_v1/rev-, I'm attempting to get an Si5351 breakout into featherwing form factor (I like the adafruit feather microcontrollers, and I like that adafruit posts their EagleCAD files on github, making something like this fairly easy to produce). There is also this for more Arduino code related to the Si5351.... https://github.com/zleffke/arduino_wspr ...my attempts at custom Arduino code, obvious from the name, I'm messing with WSPR, but the base code for interfacing with the chip is in there as well as an example (I use the etherkit libraries, unmodified). For the last two links.....USER BEWARE....not sure if I actually know what I'm doing yet or not (though my breadboarded WSPR transmitter based on this chip appears to work just fine). Hihi
Hope this helps! Slight tangent from the core L-Band discussion, but relevant. -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
Sent via AMSAT-BB@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
On 05/14/20 13:57, Leffke, Zachary via AMSAT-BB wrote:
Again, not a drop in replacement for something like the DigiLO (Though I did confirm the digiLO has specific switch settings that would produce Ifs at 2m or 70cm for a 1265-ish RF freq.....there are a couple options). The Si5351 goes up to 160 MHz for starters (not 6 GHz), is a square wave generator and produces lots of harmonics (filters!)........but it is cheap, simple to use, and that first link above shows how to make a pretty cheap, GPS disciplined signal generator.........There are other 'watch outs' about the base crystal frequency when using the higher frequencies....not sure exactly what the issue is, something about step size......but that's the fun of homebrew.....lots of threads to pull.
Zach,
Someone industrious person could create a break-out board for the MAX2870/MAX2871 and get 6 GHz. It would require careful engineering, but would be interesting.
--- Zach N0ZGO
Sorry for the dupe 'Main Zach' (I'm the other 'Zach in a hat'), meant to send to the list.....
Def agree that would be awesome.......I've looked into doing a layout myself, but as always got distracted by other projects and my coding skills are quite lacking when talking about the base C libraries for interfacing with chips like this, which unfortunately tends to discourage me if I don't know for certain there is already a library somewhere.....(preferably for Arduino, another limitation in my case, wish I were more comfortable with TI chips.....).
But, I did just find this (though commit history goes back a few years......not sure why I didn't find it way back when, but also not surprising), and there may be other libraries out there now (or more that I missed back when I was looking around).
https://github.com/PeraZver/Microwave-Transmitter
KiCad designs and Teensy SW (maybe Arduino compatible or easily portable) for controlling the MAX2871. Haven't actually downloaded and taken a look, so no idea if it works, but it looks encouraging, looks like there is also a digitally controllable attenuator for tighter output level control......the images alone look like they have maybe 0402 and smaller components (that would be a challenge for me with my little tweezer/hotplate surface mount technique......0805 no prob, can do 0603 if necessary......anything smaller and I get 'twitchy').
Might be worth giving it a shot.....
-Zach, KJ4QLP
-----Original Message----- From: AMSAT-BB amsat-bb-bounces@amsat.org On Behalf Of Zach Metzinger via AMSAT-BB Sent: Thursday, May 14, 2020 3:06 PM To: amsat-bb@amsat.org Subject: Re: [amsat-bb] L band gear
On 05/14/20 13:57, Leffke, Zachary via AMSAT-BB wrote:
Again, not a drop in replacement for something like the DigiLO (Though I did confirm the digiLO has specific switch settings that would produce Ifs at 2m or 70cm for a 1265-ish RF freq.....there are a couple options). The Si5351 goes up to 160 MHz for starters (not 6 GHz), is a square wave generator and produces lots of harmonics (filters!)........but it is cheap, simple to use, and that first link above shows how to make a pretty cheap, GPS disciplined signal generator.........There are other 'watch outs' about the base crystal frequency when using the higher frequencies....not sure exactly what the issue is, something about step size......but that's the fun of homebrew.....lots of threads to pull.
Zach,
Someone industrious person could create a break-out board for the MAX2870/MAX2871 and get 6 GHz. It would require careful engineering, but would be interesting.
--- Zach N0ZGO _______________________________________________ Sent via AMSAT-BB@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
For other LO considerations:
https://zl2bkc.com/projects/zlpll/
I've all three... (DigiLO included)
Mike
On 5/14/2020 2:57 PM, Leffke, Zachary via AMSAT-BB wrote:
Following up on an earlier request from Ed...here is the QEX article on a GPS Disciplined VFO based on the Si5351
https://hamsci.org/sites/default/files/publications/2018_QEX_Downey_GPSDO_Si... (link will download a pdf).
There are a lot of example projects out there in terms of example Arduino code and libraries for controlling the Si5351, particularly if you google 'Si5351 WSPR transmitter'. I saw at least one post about some building a quadrature LO out of one as well (implying some ability to control phase relationship that I don't fully understand yet between the three outputs). 'etherkit' and some of the products on QRP labs (that use the etherkit software) are also useful search terms.
Also the adafruit breakout can be found here: https://www.adafruit.com/product/2045, approx. $8. The etherkit folks also make a breakout board: https://www.etherkit.com/rf-modules/si5351a-breakout-board.html ($10) which is the one used in the above link (though they are pretty interchangeable). The base part is something like $2 on digikey for the custom PCB enthusiasts.
Again, not a drop in replacement for something like the DigiLO (Though I did confirm the digiLO has specific switch settings that would produce Ifs at 2m or 70cm for a 1265-ish RF freq.....there are a couple options). The Si5351 goes up to 160 MHz for starters (not 6 GHz), is a square wave generator and produces lots of harmonics (filters!)........but it is cheap, simple to use, and that first link above shows how to make a pretty cheap, GPS disciplined signal generator.........There are other 'watch outs' about the base crystal frequency when using the higher frequencies....not sure exactly what the issue is, something about step size......but that's the fun of homebrew.....lots of threads to pull.
For the really adventurous that like messing with untested HW and SW, there is this: https://github.com/zleffke/kicad_wspr/tree/master/si5351_featherwing_v1/rev-, I'm attempting to get an Si5351 breakout into featherwing form factor (I like the adafruit feather microcontrollers, and I like that adafruit posts their EagleCAD files on github, making something like this fairly easy to produce). There is also this for more Arduino code related to the Si5351.... https://github.com/zleffke/arduino_wspr ...my attempts at custom Arduino code, obvious from the name, I'm messing with WSPR, but the base code for interfacing with the chip is in there as well as an example (I use the etherkit libraries, unmodified). For the last two links.....USER BEWARE....not sure if I actually know what I'm doing yet or not (though my breadboarded WSPR transmitter based on this chip appears to work just fine). Hihi
Hope this helps! Slight tangent from the core L-Band discussion, but relevant. -Zach, KJ4QLP
That's an interesting site. The hb antenna I mentioned using is similar to the dl6wu 12 el with folded dipole. A design that caught my eye was the piston trimmer gamma match arrangement. Clever. Simple. Worth a try. Be interesting to see what the VNA thinks about it. Thanks! Ed K9EK
On May 14, 2020 at 2:45 PM Zach Metzinger via AMSAT-BB amsat-bb@amsat.org wrote:
On 05/14/20 13:41, Greg D wrote:
You'll also need an antenna. Surprised that's not been mentioned in this drift into homebrewing...
Before I got my 30 element Beam at a swap meet, I was using a homemade 17 turn Helix. It was easy to make, and worked quite well. I would not say that the beam was any better, especially since the helix is circularly polarized. I still have it, and may swap it back into service some day.
Yep! Plenty of designs out there, should one want to build vs buy:
https://vk1sotaon23cm.wordpress.com/23-cm-antennas/
One of these cheap, perhaps-not-perfect-but-good-enough VNAs would help tune it up:
https://www.tindie.com/products/hcxqsgroup/nanovna-v2/
(I have the v1, which is good up to ~900 MHz, and have been pleased with it.)
--- Zach N0ZGO _______________________________________________ Sent via AMSAT-BB@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
Zach Metzinger via AMSAT-BB wrote:
On 05/14/20 13:41, Greg D wrote:
You'll also need an antenna. Surprised that's not been mentioned in this drift into homebrewing...
Before I got my 30 element Beam at a swap meet, I was using a homemade 17 turn Helix. It was easy to make, and worked quite well. I would not say that the beam was any better, especially since the helix is circularly polarized. I still have it, and may swap it back into service some day.
Yep! Plenty of designs out there, should one want to build vs buy:
https://vk1sotaon23cm.wordpress.com/23-cm-antennas/
One of these cheap, perhaps-not-perfect-but-good-enough VNAs would help tune it up:
https://www.tindie.com/products/hcxqsgroup/nanovna-v2/
(I have the v1, which is good up to ~900 MHz, and have been pleased with it.)
--- Zach N0ZGO
Wow, love some of those designs. Quite creative.
My helix was pretty basic. It ended up being 17 turns because that's where I ran out of wire :) I didn't (still don't) have any equipment to tune it up, so just depended on the helix being inherently pretty forgiving to make it all work. I forget the exact dimensions, but the idea was to mark the wire every "x" millimeters, then twist and stretch the turns to space them every "y" millimeters. I can't find my reference to "x" and "y", but I expect x is one wavelength at the target frequency, and y has something to do with the speed of light and the velocity factor of the winding, with the idea that the rotating wavefront basically screws itself onto the helix winding. There are a number of "helix calculator" sites where the dimensions can be generated.
http://home.wavecable.com/~ko6th/IMG_0138.JPG
Fun project.
Greg KO6TH
participants (5)
-
EDWARD KROME -
Greg D -
Leffke, Zachary -
Mike Seguin -
Zach Metzinger