Amateur Radio Hardware

Mobile Radio Upgrade

I’ve had great service from my trusty Yaesu FT-7800E transceiver for around 15 years. It’s lived in a few different vehicles, performed really well and been easy to operate on the go. That is until a few months ago, when I started to get reports from other stations that my transmitted audio was weak intermittently…

Mobile radios can sometimes suffer, given the harsh conditions of mobile radios in terms of vibration and extremes of temperature. Cleaning all of the plugs and sockets on the connecting cables would usually fix things, but sadly not this time. Even swapping the microphone didn’t help.

Studying the circuit diagram, I found there are a few semiconductors in the transmitted audio signal path which control gain and it seems one of these might have become faulty. Due to lack of time and the small surface mount nature of these parts, I decided the easiest fix was to upgrade the radio to a newer model. I’ll repair the FT-7800E in due course, as I need a dedicated radio in my shack to park on the local FM repeater channels.

I chose another Yaesu transceiver for the replacement, and went with the FTM-300DE. This offered more features than the radio it replaced:

  • True dual band allowing simultaneous reception and transmission
  • C4FM Digital Voice capability, and access to internet gateways
  • APRS (Automatic Packet Reporting System)
  • Bluetooth
  • MicroSD card for easy programming of channels
  • And finally, a fancy colour screen!

The only drawback compared to my current radio was that the microphone attaches to the radio body, rather than the display head so I had to reroute some cables in my vehicle:

A mess of wires behind a dashboard

I also had to change the antenna on the vehicle roof. My previous antenna was designed only for UHF use on 70cm. The new radio would need to transmit regularly on 2m VHF as well as UHF, so I swapped to a dual band antenna, which was also slightly shorter. I’ve lost some of the range I had on 70cm, but I’ve gained 2m TX capability and of course APRS.

After an afternoon of fiddling around, the new radio body is hidden away with the control unit neatly on the dashboard and an extension speaker providing crisp audio directly into the cab:

Final install with dashboard refitted

I didn’t really think I needed APRS, but it has been interesting so far. I’ve had text messages from stations in neighbouring countries who have received my position beacons, which has allowed me to assess how far my signals are travelling. I can see local amateurs driving around near me, so I know to give them a call. One day, I started receiving position reports from lots of stations I don’t normally hear. So the radio is automatically giving me a ‘heads up’ on enhanced propagation events without me having to pay too much attention. Finally, the location of my vehicle is recorded by the APRS internet system, and so I can be tracked live on websites such as Google Maps APRS and this has resulted in a fresh cuppa being ready as I pull up outside home!

I’m usually monitoring the local repeaters GB3GD and GB3IM as well as the FM and Digital Voice calling frequencies when I’m driving around. Feel free to give me a call!


Putting the Weather Online

For Christmas I decided I would like my own weather station. I knew that I wanted it to upload the data to the cloud so that I could see trends and access the information from anywhere.

I did a fair amount of research and settled on what I wanted, but the UK company wanted to charge me about £45 on top of an already steep price just to ship it to the Isle of Man! This seemed a little bit excessive, especially as they were only shipping by Royal Mail, so I decided to look elsewhere.

I came across a website supplying a whole host of Youshiko branded weather stations. I couldn’t find much information about these online, and suspected they would be of dubious quality, but took a punt anyway.

I was pleasantly surprised. The build quality isn’t *that* bad, and everything worked first time and was easy to set up. The external sensors are powered by AA cells, and use an 868 MHz link to the mains powered indoor display unit. This unit then connects over WiFi to my LAN so that it can send the data on to two popular online weather sites.

The internal unit has a web server built in, so it was easy to add the necessary API keys for the online services. Data was flowing from my back garden to the internet within minutes of powering the thing up for the first time.

Accuracy seems OK for the price. Both the local temperature and atmospheric pressure agree well with the Ronaldsway Meteorological Office, at EGNS. My device was even sensitive enough to capture the pressure shockwave from a volcanic eruption about 10 thousand miles away!

I suspect the Manx wind and rain will finish off the outdoor unit within a year or so, but time will tell. Certainly it’s not a serious weather station, but for casual hobbyist use I would recommend these as easy to use and accurate, with the ability to upload to the cloud.

You can see the data for yourself by visiting:

Hardware Stuff

Ad-Blocking On The Go

After a recent trip away and having to endure the torrent of adverts and tracking that hotel WiFi and mobile internet connections provide, I was definitely missing the ad-blocking features of my Raspberry Pi running Pi-Hole back at home.

I’d also been thinking for a while that I should do something about securing my phone a little bit from the risks associated with using an unencrypted WiFi connection like the one available to me at work. Using insecure WiFi is a bad idea because anyone else on the same network can examine your traffic and potentially log in to all your internet accounts by stealing session cookies and account details.

So, I decided to add PiVPN to my Raspberry Pi and Pi-Hole setup. Now when I’m away from home, my phone encrypts all of its traffic using WireGuard and sends it back home to my Rasberry Pi. Here, all the usual blocking of adverts and trackers happens and I get the same nice experience out and about as I do at home. There’s also the added peace of mind that means nobody on an insecure WiFi link can see the traffic between my phone and the internet any more – everything is encrypted on its way back to my house. Lovely.

PiVPN was a breeze to set up. It took just seconds to install and set it up, and adding the phone’s connection was as simple as pointing my phone at a QR code. Amazing work by the community.

Hardware Stuff

Fighting Back Against Internet Advertisements

I’m old enough to remember the World Wide Web in its infancy in the early 1990s, when the focus was on information sharing. These days the main aim of the web seems to be to make money by tracking people’s habits and showing them adverts.

I missed the old experience, and I wanted some protection against being tracked everywhere online, so I installed Pi-Hole on a Raspberry Pi and tucked it away behind the sofa. It was very easy to set up, and has worked perfectly for over a year, protecting all of our devices from the spying panopticon of advertisers.

I have genuinely been surprised at just how much of modern internet traffic is related to tracking and adverts. In fact, my Pi-Hole has blocked more than half of the total requests for data! That’s right – there’s more stuff flying around for the adverts and trackers rather than the actual content that you see. Crazy.

With Pi-Hole blocking things silently, you end up with cleaner web pages without the clutter of adverts, and pages load noticeably faster when they aren’t reporting back to big brother too. Mobile apps and games no longer show annoying full-screen adverts and things just work much much better.

In fact, Pi-Hole blocking has been so good that as soon as I go out and about away from my home network it is very jarring to see the internet as everyone else sees it. Full of adverts and junk. Yuck. I do have a plan to fix that little problem soon though…

Amateur Radio Hardware

SDR Trouble

One of my colleagues asked me to have a look at receiver that wasn’t behaving well. It was one of the many USB receivers that are around based on the RTL 2832U and Rafael Micro R820T tuner chips. The device was very intermittent, but he wasn’t sure if it was a problem with the hardware, or with the software (and drivers) on his Windows PC. I don’t run Windows myself, so would be able to easily rule that out as a potential problem.

On connecting the device up to my Linux machine, it appeared to be behaving itself and showed up listed as a DVB-T device when I typed ‘lsusb’ into my terminal. However, when trying to actually use the device, it returned lots of errors before disappearing from the USB bus. Re-plugging it would make it come back to life again.

In my experience, complex microprocessor based things generally either work or they don’t. So to see a device that would speak happily over USB but fall over when used was a bit odd. What might cause something to misbehave in this way?

Thankfully my first hunch was correct. I swapped the rather long and thin USB cable for a short fat one. Hey presto – the device behaved perfectly and I left it running for a few hours without any issues. The resistance in the original cable, combined with the high current draw by the receiver was causing the voltages to drop, interfering with the normal operation of the device.

So, it’s always worth trying different cables when troubleshooting something, even if (as in this case) the original cable appears to be doing its job.