Updates on Portable Satnogs

 

 Here is an update on my portable satnogs rotator rig. 

I control using Bluetooth, and Stream data over Spyserver.

All runs on 12v either batter or PSU. 

Antenna is collapsible, tripod is colllapsible, rotator can be removed. 

Youloop + Preamplifier = HFmazing

 It was that time of year just now, Black Friday - Cyber Monday. I found a great deal on a Youloop antenna which included a little blue preamp box. 

My HF 0.5-30Mhz experience has exclusively included an RTL-SDR dongle and an Airspy Mini with Spyverter upconverter. I used a random longwire with balun stuffed in my attic and thought I was getting ok reception. However I can now confirm that it sucked horribly and my new youloop with preamp antenna is quite simply amazing. My HF experience is what I consider to be incredible. I would never think it possible to receive so many signals so clearly and noise free using an indoor antenna, but here I am raving about it. I feel like I have been given a new gift, a feeling of joy excitement and love for radio.

I am not or have ever been paid to endorse things so I hope you can understand when I write so highly of a piece of equipment. Using the Youloop and preamp with airspy mini + spyverter is just mindblowing. Go get one and watch your SDR waterfall light up and come alive. 

With the Airspy mini + spyverter & Longwire unun it is: Meh....
With the Airspy mini + spyverter & Youloop it is: Uhhhh this is interesting....
With the Airspy mini + spyverter & Youloop + Preamp it is:Hollllly Sheeeeeeeeeeeee!!!!!

I can't really say much more, i'm getting 80m Ham crystal clear, Volmet, DX, SSTV, So so much.

Buy it and relight your love for radio.

Updates on portable parabola antenna

 Just a quick update on my portable parabola design. From the first version I wanted to add a few features such as
-having the coax go through the centre tube and have a connector at rear.
-using a solid tube for the whole centre pole to increase rigidity over the first version
-designing various feed horns, at the moment i have feeds for 1.7ghz(hrpt), 1.5ghz(inmarsat) and 10ghz(Xband).

For a 1 Metre parabola the weight is around 350g and the pack away size is very satisfying.

redesign images are below. I find the more I make redesigns the more time consuming manufacturing becomes, I might sell as a kit thus putting the build time upon the buyer.

X-Band LNB for receiving QO-100 sat

 

X-Band LNB mount

iteration using 3D printing design

magnetic holder for phone

coax connector at base

Thanks for reading.

Parabola design

 For a while now I have been designing parabolic reflectors for Space satellite research purposes.

One of my favorite parabolic antenna of all time is the erectable S-Band antenna used by the Apollo 12 space mission.

A super lightweight highly engineered device.

It's purpose as in the description was to be a compact erectable antenna which would open out into both a receiving and transmitting antenna to send and reeive S-band frequencies directly from the Moon surface to the Earth.

So I have been looking into it to reproduce.

Here's my working functional prototype. it is 1m diameter and the feed is desgned for 1.7ghz reception of weather satellite data.

Slide arm design.

at it's full erection.

Here we see the opening and closing in action.

Anyway, i'm forever continuing the iterations and it's functioning better than i expected. I hope I did NASA proud :)
Oh and i'm now a fully qualified certified Devops and Cloud computing specialist. Go me!

Thanks for reading.

Things this week

 I have been doing a few things this week. 

I re-did my ebike. I built it in 2016.

 

 

And it is still going strong, same batteries still working, same motor, same everything. Brake blocks have been replaced a few times. It has paid for itself many times over, and given wonderful freedom and mobility to my everyday life, taking care of grocery shopping, adventures, food delivery work, alsorts. It is over 6 years ago it was built and it still goes fine. You can read about that here.

I decided to give it a few new things.

I scrubbed it clean, removed the decals and made it look all polished. I added full rain fenders. I relocated the 10ah 48v lipo battery to hang from the top tube. New Schwalbe Energizer tyres which are just amazing. And I added some suspension forks to cancel out the potholes. Much smoother ride.

So that's that.

I also have been experimenting with Horn antenna for satellite data tracking.

 

 

Using hardware store xps foam cut into shapes.

working along side a helical antenna.

We start to shape the horn.

 Then we repurposed all these scraps to line the horn.

Creates microwave reflectance.

Me so Horny.

So that is that. Test results coming soon.

HF Airspy Mini + Spyverter + Random Long Wire

 

Hey you. Look what I got. Thats right, I got an airspy mini & spyverter :)

I have had the airspy mini for a while now, I use it for listening to satellite communications. It seems to be my go to SDR, having also a RTL-SDR and an SDRplay RSP1. I won't go into reasons why it is my go to more than that it is more able to pick up signals and is more user friendly with my computer, and has bias tee.

my rtl sdr HF usb dongle - beginner level on HF?

I wanted to see if I can extend it's capabilities to using HF bands (0-30Mhz) just to be able to explore RF and learn a bit more. I tried with my RTL SDR HF dongle which gives basic results (0-14Mhz) but lacks bias tee and has EMF noise in the waterfall, the SDRplay has good potential but it is so terrible at integrating with SDR# or SDR++ on Linux or Mac it is just not worth going down the Rabbit Hole; if this issue is sorted then I might come back to SDRplay.

So, I bought myself an Airspy Spyverter last week and here are my first impressions. I bought all devices myself and I am not doing paid promotions or product endorsements.

Firstly, the Airspy and Spyverter do not come with a printed manual, so you must research ho to hook it all up correctly or else you could damage the devices. I connected my Airspy Mini & Spyverter up like this:

note the position of the micro usb socket on the spyverter. It helps to know this for orientation. Also it is suggested not to connect usb power to it while at the same time using bias tee power, as it might cause damage.

I get it connected like this:

I stuck on the self adhesive heat sinks to the airspy mini as i was worried about the amount of heat it produces - I am told on forums that the very high heat is a normal feature of airspy mini, similar to the heat produced from running Jetson nano's, Raspberry pi 3's or 4's wihout heatsinks or fans attached.

My antenna for basic first time HF reception is a random long wire antenna connected to a 9:1 unun. I use over 16m of wire for the main element, and a few metres of wire going to a grounding source which is supposed to reduce electrical noise. in between I use a self-made unun/balun using a ferrite ring, wire, and connectors housed in a plastie box:

my homemade 9:1 unun/balun

And so onto the results of the Airspy mini + Spyverter HF combo. Am I pleased?

Well, it's a mixed bag. I am only a week or so into using it so perhaps I have not got the setup creases smoothed out yet. 

Things I like about AirSpy Mini + Spyverter:
1 - this combination gives me the HF 1-30Mhz I was looking for (the rtl-sdr only does 0-14Mhz HF).
2 - the gain controls seem to actually have an effect on signal performance.
3 - it is more straight-forward to get up and running receiving signals.
4 - it has bias tee power.
5 - I am definitely getting more radio stations than I did with either RTL-SDR HF dongle or RSP1 dongle.
6 - The stations I get are more clearer than when using either two other dongles.
7 - using the Airspy Mini + Spyverter with SDR# software, it is the best combination I have used to fine-tune audio and noise reduction to achieve clear speech even in high static, faint HF radio stations. It almost seems like a magic trick sometimes.

Things I am yet unsure about Airspy Mini + Spyverter:
1 - Is my location in the centre of a busy built up urban area causing me to pick up more EMF and RF noise using the more sensitive Airspy mini?
2 - What is causing the different wave pattern in the SDR software?
3 - Is my antenna sub-par?

Using the various SDR devices I own, they all produce different and varying outcomes on the RF waterfall of various SDR computer software. As a mostly MacOS user I have used GQRX, CubicSDR, SDR#, and SDR++.

I tend to use different software packages mostly because as yet, I haven't been able to find a one-for-all complete software package yet. SDRplay devices are the big stumbling block here. My RSP1 I can only get working using CubicSDR on Mac or SDRuno or SDR# on Windows 7/10. I  very rarely use my RSP1 maybe once a month I take it out the box, and that is just to compare against other devices.

SDR++ comes close to being the most one-for-all complete package, but as yet, it does not have the magic audio processing that SDR# has. And as you may realise, SDR# is a Windows only package. Having a Mac version would be tremendous. Many people would be happy.

So onto my signal tests.

Using my Airspy Mini + Spyverter combination, it does undoubtedly produce lots more radio stations and listenable signals for me than my other devices. It is as simple as that.

However I am now contending with some other things which I want to know more about and try to find solutions for.

Mostly. What is causing these RF peaks?

When I read up on HF sdr, I saw waterfalls which looked like this:

Nice, flat spectrum, with nice clear well-defined station peaks. 

Using my Airspy mini + Spyverter setup I get this:

I get the nice clear well-defined station peaks. But I also get this huge fat arch of doom. Why do I get this? What is causing it? Why! Why! Why! My life!

I don't get this result using RTL SDR HF dongle, but I also get fewer clear stations. Here is my result using RTL-SDR HF dongle:

 

Is it because the Airspy mini or Spyverter is damaged?
Is it because the Airspy mini and Spyverter are more sensitive to ALL RF signals including noise?
Is it because of my long wire antenna?
Is it because of my location and my antenna position (in the attic of my end terrace urban house)?

I can reduce this mound by reducing the airspy mini gain to level zero or 1, but also I reduce the clear stations too, they are synchronous:

Airspy Mini + Spyverter set to Linear gain level 16:

 

 

 Airspy Mini + Spyverter set to Linear gain level 8:

 

 

RTL SDR HF Dongle set to max gain level 49dbi:

Using Airspy min + Spyverter this mound also exists all through the HF reception, an example at 7Mhz is here:

I have tried to correct using:
- Ferrite chokes on the wires - no noticeable difference

Then:
- Testing on a different computer, a laptop:

Laptop - Airspy Mini + Spyverter + Long Wire antenna set to Linear gain level 16: 

 Laptop - Airspy Mini + Spyverter + Long Wire antenna set to Linear gain level 8:

 It seems to be a different RF noise pattern than with Desktop computer. So what now?

- Testing with a different antenna:

I try also using a simple telescopic antenna with 'First test' Desktop like this:

Airspy Mini + Spyverter set to Linear gain level 16 (using simple telescopic antenna): 

 

It looks like the RF noise 'Desktop' mound is gone, but I think it is because the antenna is simple, it is not picking up stations as good perhaps less sensitive? It is similar to Airspy Mini + Spyverter set to Linear gain level 2 or less.

But because my RTL-SDR HF dongle at full gain is not making this, then it could be assumed that it is something to do with the Airspy mini + Spyverter combination? or Long wire Unun Antenna? What next?

It seems that with the Airspy mini + Spyverter combination it is much more sensitive to RF noise from various things perhaps?

So what next?

Further tests:
- Testing outside far away from the house.
- Testing using laptop on battery power instead of AC power adapter.
- Testing using a antenna far away from house.
- Somehow shielding from RF the Airspy mini more? Or is the noise coming from USB computer?

Will update soon.

My HRPT setup

Hello there, I would like to share with you my HRPT satellite setup which I use to collect weather images.

It is a 1m folding parabola with a custom antenna feed tuned to 1698Mhz. It all mounts onto a tripod, but I tend to hold it and handtrack the satellite. It is extremely lightweight and as such it is comfortable to hold for a 14 minute pass without feeling like you need to put it down. It allows you to track very accurately.

It all fits nicely together, and it can be quickly taken apart and stored safely.

I use a Nooelec Sawbird Goes+ LNA along with an Airspy Mini. I power the Sawbird using an external Bias Tee because the spec sheet says that the airspy mini is unable to power the LNA effectively.

Sample images using this setup:

NOAA 19

Meteor MN2

I capture using satdump, I use the live decode feature and the image is produced just after the satellite has passed.

If you would like one of these setups please get in touch or if you have any feedback please let me know.

Thanks for reading :)

Harmonic Drive Antenna Rotator

Here is an example of a Harmonic Drive rotator I have been working on.

Video example 1:

Video 2:

The antenna in this example is a 1546Mhz Helical.

Thanks for reading.

:)

What...The...F....Unun?

 

Hi, Yesterday I decided to test a long wire antenna I got cheap last year. It came with a 9:1 Balun...Or so it was advertised. Anyhow, I decided after first test that it worked, but I wanted to open it up and have a look inside to see what was going on.

 Opening her up there seemed to be a spare loose wire. So I posted a quick question about it over to the nice bunch at rtl-sdr group on facebook. It quickly turned heavy, and we all debated Balun vs Unun until the sun came up.

But some great information was given, and we decided that this cheap WTFun must in fact be (possibly) a type of unun. It is still ongoing lol. Balun/Unun/Autotransformer Balun. You tell me in the comments.

So anyway, today I decided to do a simple test to see if any of the suggested alterations help with signal noise or performance.

To test, I soldered some dupont connections to quickly allow me to change through the ideas.

Pin 1) dupont pin soldered to original loose wire which we think should be counterpoise/GND or to pin 2

Pin 2) Another dupont pin to test the connection that Watcharapong Chuginda did

Pin 3) Another dupont pin which runs a few metres of wire to a crocodile clip to connect to a good ground source.

Pin 4) Another dupont pin to connect to Ground/Counterpoise on pin 3

Now to test (p.s i don't have an antenna tester yet, so I have to just compare in SDR software sorry for my amateurishness haha)

So onto the quick test.

Test number one) - in original format

 

Connecting up the long wire to the WTFun Red connector, and connecting RTL-SDR device to BNC connector at the base.

Picking up some signals on 19Mhz. It seems to be a good day to get HF signals, yesterday was stormy and things were dropping in and out a lot. from 1Mhz-30Mhz I can receive some stations.

I am however getting quite a lot of static and what seems to be POCSAG interference/overloading as I am in between two hospitals. There must be a lot of pagers going off.

Test number two) Pin 1 to Pin 3

Ok. Looking at the same 19Mhz station, it seems to be a little bit stronger, clearer, less noisy.

A marked improvement. The POCSAG interference seems to still be there. But stations which were inaudible before are now listenable. I can pick up stations at 7Mhz. 9Mhz is much more strong than before.

Test number three) Pin 1 to 2

 

 

This connection was described by Watcharapong on the RTL-SDR group.

 

Seems to be between the factory wiring and setup two. There is a signal improvement, however it does not improve as much as test two. It feels a bit different does test three.

Test number four) Pin 1 to Pin 2 - and - Pin 3 to Pin 4

This setup was suggested by Harold over at RTL-SDR facebook group. It seems to work similarly as test two and three.

The same 19MHz station comes through well. I'm starting to struggle to hear any major differences to the tests apart from the original wiring as that was definitely worst of all.

Bonus test five) - Pin 3 to Pin 4
For some strange reason... I don't know why, this wiring setup seemed to be best of all.

Things just seemed least statically noisy, stations seemed clearest. I have no idea how or what the maths onvolved is, but it's just an observation. It is a narrow margin but I think this might be the best. Correct me if I am wrong.

Conclusion
It seems for now I am choosing test 5 setup. it is all about personal preference, but at the time i did this test it seemed to give the clearest sound.

The test shows that connecting a ground or counterpoise is the most important thing to add to this 9:1 WTfun (balun or unun?) to obtain a much improved signal compared to how it arrives from the store. I would say it is junk as it comes from the store. However making a simple ground connection will significantly improve it to the point that I feel I already have made progress with my HF reception.

I would like to thank all the RTL-SDR contributors over at the Facebook group for making suggestions and providing feedback. I hope this provides some answers to this device for others.

Thanks for reading.

Update:

For comparison to the wtfunun from china, this morning I made a true 9:1 Unun using a micrometals toroid and It provides significantly stronger cleaner HF reception. So there you go
Thanks again for helping. I plan on later removing the insides of the wtfunun and placing the micrometals unun inside.

Reference Circuit:

Update 2:
I rewired the Wtfunun. I learned that if we follow the above unun schematic then the wtfunun is wired backwards. I did not have to rewind the wiring just change the connections to the above image.

rewired to match the wiring of the micrometals unun i made. Now testing it with gqrx

 

rewired wtfunun to 9:1 unun top, micrometals 9:1 unun bottom

 

It is similar. But different if we look around 1Mhz the radio stations are much higher peaks.

Now, I must work on reducing overall RF noise
- setup long wire outside instead of attic
- Try SDR HF using battery power instead of household mains
- Go out to the countryside and test
- Try a different HF adapter such as Airspy spyverter.

I read that most RTL SDR devices use a 1.2v switching power supply and that it is a source of harmonics and RF noise. I could modify the pcb, but I may just search for a better noise-free device.

Thanks.