How To Build A MILSAT SATCOM Turnstile Antenna

Here I build a Turnstile antenna for UHF, specifically for listening to MILSAT SATCOM satellites.
RF Vector Analyser Used To Check VSWR:
uk.banggood.com/custlink/mKv5...
s.click.aliexpress.com/e/_ExL...
Original Blog Post:
diebastelkammer.wordpress.com...
3D Print I used:
Flashforge Adventurer 3
s.click.aliexpress.com/e/_Dlr...
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[@coriscotupi]

For anyone wondering, in the hilarious exchange heard from 07:04 the guy is talking about the day he crashed his vehicle into an F-4000 truck because he was mesmerized by the hot blonde lady catwalking down the street. He didn't notice that the truck ahead of him had stopped, and he rear-ended into it. He then wraps up the narrative with an expletive at 08:03. 😂

[@timdixon1166]

Hi. Small tip...trim the sharp corners off the ends of the elements and put some tape/heatshrink over them or you will scratch everything it touches if you are going to carry it around!! I used tape measure antennas for foxhunts for many years...

[@AustinSteingrube]

If anyone is doing an antenna build and can’t get solder to stick, three tips: Use a bit of fine sandpaper to remove oxidation, apply generous flux, and use silver solder.

[@rRadioON]

Use soldering acid :)

[@chrishammett119]

Nicely done turning a very costly antenna into a perfect DIY project that really does not take up that much time. Very cool and well presented. Thank you, Keep up the great videos,

[@TechMindsOfficial]

Thank you very much! Your comment is MOST appreciated!

[@AdamSWL]

Well done Matt! Some black glue lined heat shrink over the elements and paint the boom and brackets. Will look the part and be pretty weather resistant.

[@beboom]

All the chats you've picked up were between Brazilian truck drivers. These transmissions are usually a bit dodgy and done using American military satellites. Considering the frequency, the type of chat you caught, and when you posted the video, I'd say that the satellite in question is the UFO 10 (also called USA 127, NORAD ID: 25967, International Code: 1999-063A).

[@g0nad716]

Another good one Matt, proper HAM radio : building stuff, testing it and move on to the next challenge. Love it thanks for the inspiration as always. 👍🏻

[@miroslavm2503]

Just to make something clearer, the SWR has very little to no impacts on the quality of signal reception but the quantity of Reactance in the overall Impedance does. So the downlink for SATCOM, that is the satellite transmissions, is between 240-270MHz (roughly) and the uplink is between 290-310MHz, this is where the channels that the satellite is tuned to receive. The SWR is important in the uplink range (290-310MHz) but in the downlink range (your ground reception) it's important that the quantity of Reactance for the antenna in the overall Impedance is as small as possible. The reactance can be Capacitive or Inductive, whichever it is, you want it to be in the pico range not the nano. So idealy you want a few tents of pF or pH up to a few hundred, as soon as you go beyond 1 nF or nH the reception will be worse. That being said, I have seen some antennas that with enough gain will work well even in those condition but it's not ideal. The radio he is using can be also found under the brand Radtel Rt-470, I have it, and it's very good, it can even transmit in the uplink band with a usable 4-4.5W. The reception is very good, better than most 100-150 USD radios.

[@dcmoisan]

There are many cheap LNA's that can be fed with 5V. Put one at the base of the antenna, and you should get excellent signals no matter where your SDR is. Nooelec sells them.

[@opastorello]

As a Brazilian, I understand a captured conversation😲

[@MhzUHF]

Love the Satellite Videos

[@florentleider222]

With a log periodic antenna 130_470, I got results at least s good as yours. The antenna was orientated broadly to the East. I had even the opportunity (about 20:00 UT) to capture a US military transmission in clear on one channel of the first pack of channels (+- 251 Mhz). I think there are others users of the milsat , which sound like russian or similar.

[@n1vca]

Wow, that works surprisingly well, considering your beautiful but "noisy" house is in the way, because the elevation is fairly low, the RX is a wideband radio with almost no preselection and most likely not an ultra low noise front end. I have had a 16 element wideband log periodic and my signal to noise with a better receiver was not better than this. It seems the SatCom satellites use a circular polarisation which I guess is one of the factors your turnstile works great and the second one is that your antenna is a resonant system for this band only. I am surprised the coax transmission line doesn't get strongly influenced by the aluminium carrier that has its own resonance and being so tight in there, there should be a capacitive coupling, shifting the phase of the transmission line away from where it should be, but in practice it seems to be good enough for a great result. I guess if you put this up on a pole/tower overlooking the houses and use a band filter for this band and an ultra low noise pre-amp, the signal to noise should be outstanding. From what I know the Brazilian pirates use helical antennas for up- and downlink, underlining that fact that a plain H or V yagi may not do the trick, because you miss one half of the energy because of only receiving a single polarisation layer. For a permanent outdoor installation a different choice of element material would be better because this stuff is great for foxhunting when running in between trees, where these bendable elements are ideal and will instantly flip back into position, while you don't want these to move with the wind 🤣 when on the roof. They may actually start to oscillate and make noises, not ideal for anyone around. And make sure to use PET-G instead of plain PLA, because most (or all?) PET-G materials are UV resistant and will not fall apart after a few sunny days. Many thanks for sharing - this is great work and I love the idea that anyone can built these for a few bucks and building something and getting good results is so much more fun to be creative than buying something ready made, because you don't learn from it.👍

[@DigiLab360]

You live in a beautiful place. Thank you for the great video. Greetings from NYC.

[@TechMindsOfficial]

So nice of you

[@sipansibabdreddknot5179]

Great video!

[@TechMindsOfficial]

Thanks!

[@dennistate5953]

Outstanding

[@victorcharlie7491]

Great info tnx bro!

[@DitoZBR]

I think you captured Brasil southwest guys. Their accent looks like folks from Rio de Janeiro. Very nice catch. Cheers!

[@winstonchurchill6506]

Used to pick these up years ago on my old standard scanner whip ariel

[@fermtr1939]

Thanks for video !!!. Very very nice yr ANT. In spanish : Muy chula tu antena. !! Thanks for video.

[@x_CrossHair_x]

Epic!! (good Job).. I Wish that I lived in your town.. (I would love if you were my Buddy) aka Best Mate. I seen your other video regarding this topic.. I did the same RX using my Helical for (NOAA weather satellite) 137-138 Mhz. It worked quite well.. but.. This project is perfect, and the best.. (Thanks for the details for this project) I don't have a 3D printer but my neighbor has one. so.. (It will finally be used for something useful 😉)...Thanks for the Post... & 73's 👍👍👍👍

[@TechMindsOfficial]

You’re welcome 😉

[@surplusdriller1]

i did make one almost finished, but when i was going to compleat it the 3d printed parts had warped, should be re designed with 2 screws on each tape mesurer

[@plenus7392]

hahahaha they are talking about having sex and crashing trucks, i love those brazilian truckers

[@ValenteEspinosa]

Nice!

[@JW12345.]

nice

[@RoadRunnerMeep]

I never thougth about using a tape measure for some cheap elements. Basic metal but strong enoughs in the lengths to stay rigid

[@aquahood]

What about multi-freq mil sat UHF/VHF I've seen the cool dual Yagi seperatrd by s beam and an aiming set of motors.

[@m6kzt]

This is seriously cool Matt, do you know the sat's callsign/designation? also I recently took down my beams so have a ton of coax... free to a good home, get in touch if you want it!

[@kensejkora4424]

Likely satellite designations WGS F1 (USA 195); WGS F3 (USA 211); WGS F5 (USA 243); and/or WGS F9 (USA 275). All four of them have a footprint that covers Europe and South America. You can map them in Orbitron, Gpredict, and WXTrack if you load the "Geo" TLE file from Celestrak for the satellitetracking software. Ken -- WB0OCV

[@bumbozambumbazebulon6738]

Awesome. Quick translation 7:07 Brazilian pirates (truck/van drivers?) possibly hailing from Minas Gerais State "can't lose dude b/c of a **unintelligible slang** once I crashed a truck because of a woman back home, in Cachoeira..." "...a super hot blonde, dude, she was fit like one those thoroughbred mares. She didn't just walk: she paraded... when I looked back forward (at the road) the Ford F4000 truck in front hit the brakes and I went *WHAMMO!*" Others: **laughs** "that's nuts!" "...**unintelligible**" asking what happened...I looked at the lass when I looked back at the road the car (in front) stopped. 'Wasn't the traffic that stopped, the car in front stopped to turn the wrong way " "...then comes another (driver) I want to go through but he comes about such as **unintelligible slang** I hit my horn full blast **unintelligible slang**... I bet he remains deaf to this very day." "... I need to get me some... 'cuz, holy f_ck"... 9:41 "(... worked until 7 in the morning.. ) 9:46 "man...spent **unintelligible** from Monday to Friday" 11:16 "how much it ended up (costing?) " "532, Zenildo said he'd give 500"

[@Djzleite]

perfect

[@raymatoso5270]

Aqui e Brasil 🇧🇷🇧🇷🇧🇷🇧🇷😮

[@rohnkd4hct260]

Not a bad looking antenna

[@matthaxx7137]

Great Video. Thank You. I feel a project coming on. Is there anything interesting to be heard apart from Brazilians shouting at each other? I don't mind if the good stuff is encrypted, I'd be happy enough to pick up different codecs.

[@W4TRI]

Do you know of a cheap Az/El system? One that you can actually get parts for now?I've seen so many attempts where someone built a one off then tossed about half of what you need to make it into a Github then it just goes away after a bit.

[@mscir]

WEll done.

[@RossJNunn]

I would love to do this project using the original instruction URL but unfortunately, I can’t read or speak German. Any idea if there’s an actual STL for this 3D print?

[@TheShaunksread]

SDR Angel has a satellite tracker etc etc

[@hotquebec]

The 3d printer presents a bit of a problem- how do I make one?

[@Alek_YU1IS]

Radiation diagram looks weird. Are directors and reflectors in contact with boom? (Not sliced in half?)

[@stargazer7644]

Yeah reflectors and directors have to be one piece and close to a half wave long. If you cut them in the middle like the driven element, they become 1/4 wave and no longer do anything. So make sure to short the ends to the boom.

[@dennis8019]

are u sure about that? @techminds can u confirm this?

[@JAKOB1977]

Dont you have one of these handheld HackRF with PP screen and speaker? I often see people turn to these when ealing with satellites. why SDRplay?

[@TechMindsOfficial]

I do indeed have a HackRF. And I used SDRPlay because that’s my main SDR which is always connected. Any SDR capable of receiving around 220 will work

[@blackops84321]

ok, it works.

[@dennis8019]

this antenna wil work also if u drop the director and the reflector.. they are not connected its only the driven elements that work.. looks cool though but thats about it.

[@jamesmoore6424]

Off the record... you could transmit yes?

[@karwanagry5387]

hi. please tell me this device how many kilometers of range,30km.50km. or than,

[@davidbridge3542]

Great presentation, but is it worth it with what you get to listen to?

[@TechMindsOfficial]

If you speak Portuguese lol.. I guess there are other Milsats to work with, needs more investigation.

[@arthurtwoshedsjackson6266]

I was thinking the same. Great build. Only ever heard either prayers in Russian , music or just general waffling in Portuguese

[@canalcomentario]

Essas pessoas que falam dão caminhoneiros brasileiros, que eles usam esse sistema em rodovias onde a fiscalização é precária.

[@tseckwr3783]

you need AN/OE-82C for a true SATCOM antenna. Of course, you might find it difficult to get onboard a US NAVY ship to take one of the two.

[@ruidelgado5294]

Brazilian...some really bad words were said

[@UrRealestCritic]

Can you TX with this antenna

[@alexjh47]

Not legally on this frequency, but even if you wanted to you'd need a radio that allows it as well.

[@Ixquick979]

Which radio is best for transmitting towards the satellites 290--320 Mhz?

[@steveparkes]

One that a licenced amateur won't point you towards due to potential licencing restrictions but those frequencies that are illegal to transmit on in my region are often advertised as 3-4 Band FM VHF/UHF transcievers and a quick look at the sales page will confirm that you will have to be careful not to transmit on these frequencies. Many devices use the same chip but different firmware and you have to be sure if you flash a new firmware on a device you're not accidentally transmitting on a frequency not licenced for use so I really wouldn't do this at all unless you happen to have an existing handset with flashable firmware that has different operating bands when sold in different countries and know exactly what you are doing. HTH.

[@gibbywankenobi66]

These are pirates transmitting on us military satellites. Might not be the best idea to transmit on them.

[@bigpimp347]

257.150 the Toad alarm, that's been on there as i know of over two years..!! why ??

[@gibbywankenobi66]

Some have said it is a marker frequency to keep it clear in case the military needs to use that frequency. They may be right. Makes sense.

[@bigpimp347]

@@gibbywankenobi66 possibly, or i thought it was a warning to tell the Military the battery was failing or some other indicator..

[@gibbywankenobi66]

@@bigpimp347 could be. That sounds reasonable as well.

[@bigpimp347]

why not just buy an old band III antenna ?? after all band II isn't far off Sat-Com frequencies

[@TechMindsOfficial]

Polarisation is a short answer. Also, where’s the fun in buying something when we can make it :) cheers

[@bigpimp347]

@@TechMindsOfficial oh so you're telling us they use RHCP or LHCP ?? also not every one has a 3D printer.. and Band III gear is readily available.. that said there was a guy selling old band III Radio or what ever they were antennas, for £14.99 which could easily cut down... tuning isn't that essential for receive, i use a simple VHF center-fed on my stack with URM76 on it.. NOW unless you wanted to TX a cheap UV-5R-III would work and of course a suitable antenna..

[@dennis8196]

@@bigpimp347 Before I owned a 3D printer I used what I had around me, wood, DIY fittings such as brackets and hinges, and if you need plastic parts made to shape, use old milk bottles heated slowly until they become 'gloopy' and poor in to a mould you have already prepared using wood or even papier-mâché. if you cant use the fundamentals to find solutions, then you could always take up other hobbies like sleeping.

[@legendarycatmaster]

This transmission is from Brazil, probably from a truck driver

[@matthewlee2686]

You should sell some kits

[@TechMindsOfficial]

I had thought about that, but to be honest it means my 3D printers would be running 24/7 lol.

[@matthewlee2686]

@@TechMindsOfficial I'll buy one if you do

[@evandroesm2009]

7:31 brazileiros falando em vhf!

[@LoftBits]

All we need now is a translation!...

[@juliorocha4178]

It's all nonsense, don't bother yourself with such conversations. The first one was joking in a rude manner about a sexy woman he met the other day. The kind of people that use to chat through this satellite is usually the most uneducated, ignorant and low level part of the population and they speak as they were on a bar or something like that. Nothing important at all.

[@beboom]

Apparently he managed to pick up a conversation between 2 Brazilian truck drivers... one of them said the following: "Once I crashed a truck because I was staring at a woman... [interference]... a really hot blonde... she looked like one of those quarter-mile racehorses, you know? She wasn't walking, she was strutting... When I looked back at the road, all I saw was a stopped car... Bam!"

[@danwalkley304]

All you need is,,,,,,, a 3d printer... lol

[@michaelmichael8406]

FWIW, many libraries have them now & there are services that will print for you from a file. That's more expensive if you do a lot, but for a one off, and cheaper, much easier, and more certain, since you are renting their expertise along with the printer.

[@miquel9898]

Way too complicated for this kind of stuff.

[@skankhunt9078]

Would this work for transmitting also?