So, I came down to the RSGB Convention to see what's what in the world of radio.
After day 1, it's been good - Here's a disorganised selection of my notes and thoughts.
Session 1: Advances in Amateur TV
Given by Noel Matthews, G8GTZ
Noel started out telling us about the bands that ATV is on these days, the ones that caught my interest were:
- 13CM (Roughly 2432MHz)
- 70CM (2MHz, Digital centered around 437MHz)
2M Digital Amateur TV is really interesting, it seems.
It's been granted 500KHz in the middle of the experimental 146-147MHz band. Usually DATV is DVB-S with 2MHz bandwidth, so working with this reduced bandwidth has forced innovation!
The BATC has worked on Reduced Bandwidth Digital TV…
- 444KSymbols/s, 7/8FEC
It has the downside of not being compatible with regular set top boxes, unlike the DVB-S/2 stuff, but it does fit within the bandwidth and work. I'm really glad to see adoption of MPEG4 in this field - it looks like the BATC will be a cool group to interact with and experiment with more efficient video codecs in the future.
Noel showed a Rasperry Pi (of course) which can take video in from a source, encode it in MPEG4 onboard (using the native hardware acceleration) and Software by F5OEO. It looks super simple and cool, I'm going to try and get this running on a raspi & something like a HackRF soon… Assuming I can get the IQ outputs to work properly!
Other helpful stuff to fall out of this talk were:
- DATV Express software
- “Mitsubishi Module” for RF Amplifiers
- F7DZP Tutioune software
- QRM on 70cm and 2m is really bad. Filtering will make it much, much better. I might need to do some filtering.
After this one, I'm really interested in Digital ATV fiddling… I probably have the tools to do it in the flat too. Mostly.
Session 2: Making the most of 6m during the Downward Cycle
Given by Peter, G3ZSS
Some cool stuff on 6m - it's becoming really quiet due to the solar minimum we're approaching, but there's some near methods of propegation that people are using and abusing to make really long distance contacts.
Short Path Summer Solstice Propagation - this one's going over the pole from EU to Japan/China/Taiwan over summer. Super interesting.
Trans Equitorial Propegation (TEP) Cutting an equal path over the equator, and combines nicely with other effects. You can have Skip into TEP and go real far from the UK. You can also ride the greyline and get into south america.
There's a Scandinavian contest we could try from Aberdeen, 2nd Thrusday of every month!
- dxmaps.com looks a useful resource
Session 3: New World of Amateur Satellites
Given by Graham Shirville G3VZV
Lots going on here, my notes are extensive. Highlights are:
- Oscar 7 is still operational This was launched in 1974 and came back to life not too long ago. That's incredibly cool - it's a satellite from before the era of microchips, so it's running solely on discrete components.
They think that years after the NiCad batteries ran out of charge they failed totally, creating an open circuit. This moved the internal busses from 0V to their intended state. When the craft is in the sun, it can transmit!
Don't use too much power into the upling, though, you'll saturate the bus and kill it temporarily.
SDR Console V3 is about to be released by Simon, GK4ELI - I'll need to have a poke around there.
E079 is due to be launched soon with a U/V Linear transponder and sit at 600KM height, should be a nice big footprint. NAYIF-1, FOX1C and Fox1D are soon to be launched too
I'm super excited for Es'hail 2 - a Geostationary satellite with huge coverage. It'll do 2.4GHz and 10GHz, space for a transponder and a couple of DVB-S2 channels.
Session 4: HF NVIS Propagation: Findings associated with the 5MHz Experiment
Given by Dr Marcus Walde, G0IJZ
This was great.
It wasn't recorded, I didn't take any notes but it was highly technical, maths-y and fascinating.
HF-NVIS is a propagation mode that really interests me, it was fantastic seeing someone talk at length and in great, technical detail about it was very enjoyable.
Major takeaways were:
- NVIS is cool
- 5MHz is cool
- Happy hour happens on HF
Session 5: Microwave Links for Remote Stations
Given by John Regnault, G4SWX
He's running a totally remote EME station using microwave link as backhaul. It's about 16KM away from home, and it seems to work very well.
I had no idea you could do this. It's really cool and it's totally captured my imagination.
John ran a couple of types of hardware:
- Ubiquiti 5.7GHz Airgrid M5
- Ubiquiti Bullet 2HP w/ 24dBi TP-Link Dish.
The former didn't work for him, but the latter did and I'm quite taken with the form factor.
The Ubiquiti Bullet is a tube which takes PoE in one end and has an N connector at the other.
With dd-WRT it'll run in amateur allocations, like 2344 MHz too. This is how he avoided QRM amongst other things. This is very cool - I'm really interested in doing high power, Amateur microwave stuff and this is a great, relatively cheap starting point.
Also interesting was:
- EP-AB003 2.4GHz amplifier
With a 19dBm (79mW) input, this will output 6.5W @ 2.4GHz-ish, and seems to work on the lower part of the amateur allocation. It costs about £40 from ebay, and I could use a HackRF as my input. It's got my brain excited.
As before, QRM is an issue (we're in the ISM/wifi bands at 2.4 and 5.7GHz after all) - filtering really helps here.
In short, John was running an SDR, with the I/Q coming over the microwave link as UDP/IP. It means he can do all his ‘real’ radio at home, and just have the last stage (I/Q Conversion, amplification) essentially on the mast at a better location. That's a really, really exciting idea that I'm super taken with.
Session 6: Raspberry Pi & Red Pitaya
Given by Mike Richards, G4WNC
This was interesting, but not as technical as I'd have wanted.
There was lots of talk about the ever popular Raspberry Pi and a brief introduction to Linux. Not the most accruate, but it was sufficient for the purpose it served.
The end was on the Red Pitaya itself, and it seems a cool device for receiving radio with.
Most exciting is the ability to have 6 or so separate receivers running simultaneously. He gave a demonstration of receiving WSPR, and it was pretty solid at doing that.
To learn more about this I think I'm gonna have to do my own research!
- HPSDR might be worth looking into!
This kind of event gets me super excited for amateur radio again. There's lots to see and do, and some really intersting stuff going on.
I'm really looking forward to joining and tracking the BATC and keeping up with developments in AMSAT-UK. Also looking into microwaves in general more, now I know it's not impossible to get into.
Time to press ahead and get that full license.