Shack maps

Maps are important to radio amateurs – We like to make contact with countries all around the world so a good map is essential.

Some years ago I bought an Amateur Radio World Prefix map from DXMaps and it’s been on my wall ever since. I noticed that there was a tiny minor printing error on the map and contacted Mike, GM0PHW at DXMaps who very kindly sent me a replacement free of charge. Thanks Mike!

I really recommend these maps, they’re large, easy to read and printed on good quality glossy paper. That makes them quite difficult to photograph and this picture really doesn’t do it justice.

Amateur Radio World Prefix Map by DXMaps

Although this is an excellent map, the one I probably look at the most is the Great Circle map I have stuck to the inside of the shack door. When you look at a flattened map, like the one above, you assume that if you want to work North America from the UK, you’d point your aerial due west. Due to the shape of the earth and how this sort of map projection works, that’s not quite true. A Great Circle map shows the actual direction to point your aerial.

As you can see from the map below, if I want to work North America, the correct direction to point my beam is from 290° to 340° not 270°. Realistically, HF beams are quite wide so that it won’t make a lot of difference to stations on the east coast but consider that New Zealand is anywhere between 10° and 70° rather than the 140° you’d think from the map above and you can see how important a Great Circle map is.

This Great Circle map was produced from NS6T’s web page here. I simply put my latitude and longitude in the Location box (although it will take a grid locator), set the maximum distance to 19500, changed the paper size to the largest available and hit ‘Create Map’. This gave me a pdf file which I took to a local printer who charged me about £3 to print it. The paper isn’t great but it really doesn’t need to be as it’s just a very quick visual aid. I did intend to find somewhere who could do it on better quality paper but this is perfectly adequate for what I want.

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A quick tip for your hotspots

With all the hotspots I have in the house for various modes, I decided to do something about the RF. They all run very low power but they’re only for me to use and I didn’t want the RF escaping the house.

I bought a few tiny little dummy loads from eBay and replaced the rubber duck aerials on my hotspots with them. I’ve checked and I can still access them from anywhere in the house and that’s all I need. I picked that supplier because he’s in the UK and delivery is very quick, there are other sellers who will supply packs of five for the cost of two from him but they’ll arrive on the slow boat from China.

These dummy loads have the benefit of being nice and small and having perfectly flat SWR across both 2m and 70cms which is far better than the supplied rubber duck aerials. Of course, if you want to use your hotspots at any distance further away then this isn’t a tip I’d recommend.

Hotspot with dummy load instead of the supplied rubber duck
Posted in Amateur radio, D-STAR, DMR, Hotspot, How to ..., Raspberry Pi, Yaesu System Fusion | Tagged , | Leave a comment

How to set up a Yaesu System Fusion reflector (YSFReflector)

Over the last four or five years I’ve been a regular user of two digital voice modes, D-STAR and DMR. I don’t particularly like to use them to work ‘DX’ but they both have their advantages regarding linking repeaters together and allowing me to keep in touch with people when I’m away from home.

Both have a relatively steep learning curve but over time, I’ve got my head around them and am quite happy configuring radios, building ‘code plugs’ (*shudder*) and operating them.

That left one digital voice mode that I’ve not yet tried; Yaesu System Fusion, often abbreviated to just Fusion or YSF. A few weeks ago I bought myself a Yaesu FTM-100DE and it’s sitting in my shack now. There are no Fusion repeaters nearby so I set up a cheap hotspot to allow me to access the network.
The first thing I’ll say is that the speaker in the FTM-100DE is rubbish! It’s tinny and the audio out of it is dreadful. I plugged an external speaker in and it’s so much better. In fact, I would say that the audio on Fusion is by far the best out of any of the digital modes.

Fusion is just as complicated as the other modes to a newcomer but I’m not going to go into that here. I’m assuming you’re here because you want to set up a reflector. I had a good reason to do that last week and I couldn’t find a complete (and accurate) guide to doing it. It was so frustrating that once I’d got one working, I decided to put together what I hoped would be a decent and easily followable guide.

I must point out that I’m not an expert. I’ve barely touched Fusion and I have a lot to learn. I just wanted to share a detailed solution to something which gave me a lot of frustration. I don’t claim to have written any of the scripts or packages used in this guide, I’m just putting everything together in one place in hopefully easy to follow steps. I have linked to the source pages I used as starting points at the bottom of this entry.

I did this on a Raspberry Pi and so my instructions are written specifically for that device. I’ve tested this on a Pi Zero W, a PiB2, Pi3A+, a Pi3B and a Pi3B+. It will not work on a Pi4 as I’m using Raspbian Stretch which is not supported on a Pi4. I’m using Stretch rather than Buster because some parts of this have been removed from Buster.

First, download Raspbian Stretch Lite and write it to an SD card. I highly recommend balanaEtcher to write the image out to an SD card. Note that we’re using the ‘Lite’ version of Raspbian so you won’t have any graphical user interface and all the work will be done from the terminal.

You will need to either give your Raspberry Pi a static IP address or set up a reservation in your router. I do this by looking at my router and checking what devices have connected and then set up a DHCP reservation so each particular Raspberry Pi I own will always have the same address each time it reboots.

Open up a terminal/dos prompt or whatever client software you’re going to use to connect to the Raspberry Pi and log in.  In my case, the Raspberry Pi is on so I use the command
ssh pi@

You’ll be prompted for a password – It’s currently set to raspberry.
Use the following command to enter the Raspberry Pi config utility:

sudo raspi-config

First of all, expand the filesystem.  You do this by selecting option 7 Advanced Options, then A1 Expand Filesystem, then select OK and you’ll be returned to the main screen.

Now select the first option Change User Password and press enter.  Press enter again and you will be prompted to Enter new UNIX password.  Type a new password, press enter and re-type your new password again.  You will get a message telling you your password has been changed successfully.  Make a note of this new password.

Use the arrow keys again to move down to 4 Localisation Options and press enter.  Use the arrow keys again to select I2 Change Timezone and press enter.  First select your Geographical area and press enter and then select your Time zone and press enter.

Now you should set your Wi-Fi country – By default, this image is set to GB (Great Britain) so if you’re in a different country you should change this to ensure that the Pi uses the correct frequencies.  Select 4 Localisation Options and press enter.  Scroll down to I4 Change Wi-fi Country and press enter. Find your country, press enter and then press enter again to return to the main screen.

Finally, select 2 Network Options and press enter.  Press enter again on N1 Hostname and give your Raspberry Pi a suitable name.

You will now be returned to the main Raspberry Pi Software Configuration Tool main screen.  Use the tab key to select <Finish> and press enter.  You will be asked if you would like to reboot now.  Press enter to reboot and once your Pi has rebooted, log back in using the new password you set earlier.  Make a note of this password because if you forget it, you’ll need to start from scratch.

If you’re using a Mac and connecting to your Raspberry Pi via the terminal you may notice the screen flashes badly.  You can fix this easily and quickly by going into the terminal Preferences/Profiles and make sure the box “Allow blinking text” is not ticked.

Assuming your Raspberry Pi now has either a static or reserved address, you can start with the actual setup.

Log in to your Pi with the new password you set above and type the following commands.

sudo apt update
sudo apt upgrade -y

This is making sure that Raspbian Stretch is fully patched as far as it will go. The first will go through quickly, the second command may take a little longer and if you’re using an older Pi or a Pi Zero, it will take a good few minutes. When it has completed, reboot the Pi.

Log back in and enter these two commands which are loading pre-requisites for the actual installation.

sudo apt install git -y
sudo apt
 install insserv -y

With those done, it’s time to download the install script and run it using these two commands.

sudo wget
sudo bash

When the install completes, it will ask you for the name and the description of your reflector. The name should always start with your two letter country code, have one space and then the rest of the reflector name. You can use a maximum of sixteen characters. For my reflector, I chose GB QSO365. The description is free text and is a maximum of fourteen characters. For my reflector, I put in the description.

Don’t start the reflector just yet though as there are some things you need to do first.

Log into your router and set up port forwarding to the Pi. This is a great site with guides to many different routers. By default the reflector needs port 42000 forwarded to it although you may find that port is already in use on your system. In my case, ports 42000 and 42001 were already being used by my Fusion hotspot so I used 42002. If you’re not using 42000 then you need to edit a configuration file on your Pi.

sudo nano /etc/YSFReflector.ini

Scroll down and change the following section:


In my case, I changed 42000 to 42002.

Save the file by pressing ctrl-x, then hit the Y key and then press enter.

Now you’re ready to start the reflector using the command given at the end of the installation.

sudo /etc/init.d/ start

The next step is to register the reflector. Head over to the Reflector Registry site and click on Register Reflector. Enter the name and the description you used earlier but leave off the two character country code from the name. You need to put in the Host/IP-Address of your internet connection (NOT your Raspberry Pi). If you have a static external IP address, enter it here otherwise you will need to configure a dynamic DNS service.

The Port is the port you configured earlier and the rest should be obvious. You haven’t set up a dashboard yet so you can’t enter that. Click Submit and you’ll get an email telling you it’s been registered with a link to click to accept the privacy agreement.

Setting up a dashboard

You could stop here but it’s not so much fun without a dashboard because you can’t see what’s going on. You can see my reflector dashboard by clicking here. Let’s install a dashboard.
Enter the following commands:

sudo apt install apache2 -y
sudo usermod -G www-data -a pi
sudo usermod -G www-data -a root
sudo chown -R www-data:www-data /var/www/html
sudo chmod -R 775 /var/www/html
sudo apt install php7.1-common php7.1-cgi php7.1 -y
sudo apt install libapache2-mod-php7.1 -y
cd ~
sudo git clone
sudo cp -R ./YSFReflector-Dashboard/* /var/www/html/

If the above commands fail when installing php, it may be because version the listed version is no longer available.  Change all instances of 7.1 for 7.2 (or 7.3, 7.4 etc) and try again.

With those commands entered, open a web browser and go to where is the IP address of your Raspberry Pi and you’ll get the following screen:

All fields on this configuration page need to be filled in, the defaults are all correct but you have to overtype them yourself. To help you out, here are all the top options, you can just copy/paste these.

The same applies for the Global Configuration section. Even if there is text in the boxes, you need to overtype it. The Timezone is obvious, the URL to Logo field can be left blank and the rest are your personal preference.

When you click the ‘Save configuration’ button, you are presented with a screen telling you to remove setup.php. Sadly it doesn’t tell you where that file is saved so here’s the command to delete it. You should also remove index.html so that doesn’t get served by default:

sudo rm /var/www/html/setup.php
sudo rm /var/www/html/index.html

If you need to edit this configuration in the future, you can do it by editing a file.  Once you’re in the file, the options are obvious.

sudo nano /var/www/html/config/config.php

In your web browser now, just enter, substituting all those xxx for your own IP address. You should be presented with the dashboard for your reflector. If you want to make this available to the outside world, you need to forward port 80 in your router to the Pi and add the dashboard link to your entry on the Reflector Registry.

Everything is done. Now you just have to wait for your reflector to appear on the list of active reflectors here which can take up to two hours. You can also search for it on the Reflector Registry as it should now show active.

By default, your Pi-Star won’t know about the new reflector until it has automatically updated overnight but once it shows in the active reflector list, you can force an update. At the top of the Pi-Star dashboard you’ll find a button called ‘Update’. Click it.

When that has finished, click on Configuration and your new reflector will appear in the YSF Startup Host: drop down box. Select it and click the Apply Changes button.

And that’s it. Although it looks complicated, it’s quite straightforward. When I ran through the complete setup to write this guide, the process took about half an hour.

The reflector I created is called GB QSO365 and the YSF DTMF code is #26368. I will leave it online if anyone wants to use it but please don’t bridge it anywhere. The dashboard can be seen by clicking here.

Finally, here’s the reflector itself. It’s running on a Pi Zero with an external USB ethernet interface. It’s not exactly high-tech.

Creating a YSFReflector
How to install a YSFReflector
YSFReflector dashboard

Posted in Amateur radio, D-STAR, Data, DMR, Hotspot, How to ..., Raspberry Pi, Yaesu System Fusion | Tagged , | 10 Comments

A new year, a new callsign

In 2013 I applied for M7P as a Special Contest Callsign, and have used it successfully in a large number of contests throughout the years. One of the reasons I chose that particular callsign was for the rarity value when working the WPX contests, my logic being that people are always chasing new multipliers and the M7 prefix was quite rare with only a potential 26 callsigns.

In October 2018, Ofcom started issuing M7xxx callsigns to new applicants for the Foundation licence and so my contest callsign suddenly lost the rarity value.

I decided that when it was due for renewal that I’d change. I’d never been entirely happy with M7P when using it on SSB as I’ve found that getting the final letter across can sometimes be difficult in crowded and noisy bands. Of course that’s not a problem on data or CW but that, combined with the reason above made me start looking around at alternatives.

I decided very quickly that I didn’t want an M prefix again, simply because what happened in October could quite easily happen again. I could have picked an unused M prefix but as and when M0s run out, I could have been caught out again.

I looked at G prefixes and immediate discounted 0, 1, 2, 3, 4, 5, 6, 7 and 8 simply for the fact that they’re still relatively common. That left me with the G9 prefix and once I started researching, I discovered that G9 callsigns have only been issued commercially for experimental purposes and never used on the amateur bands. This doesn’t include the G9+1 callsigns that are now issued as Special Contest Callsigns.

The RSGB post a list of which Special Contest callsigns have been issued and at the time I checked, there were just nine G9+1 callsigns. I looked through the list and decided to apply for G9D.

My application form was duly completed and emailed on the 1st January 2020. At 09:00 on the 2nd January I received confirmation that G9D has been issued to me.

I’ve got this callsign for at least five years and I’ve already registered it with LoTW so all QSOs made using it will be uploaded there. It’ll be a few years before solar cycle 25 kicks in properly but I’m looking forward to giving it a good airing.

If you hear G9D during a contest on SSB or CW or see it scrolling up your screen during a data contest, please give me a call!

Posted in Amateur radio, Contesting | Tagged | Leave a comment

A personal, non radio related update.

It’s not often that I write an update here that’s completely unrelated to radio but it’s time for that now.

On the last day of November, I visited a friend of mine who lives about a mile away for a meal and a couple of drinks. Although it was a cold night, it was dry and I decided to wrap up warm and walk home. I’m no stranger to walking – I’ve been carrying a Fitbit tracker since 2011 and in that time I’ve walked nearly 15,000 miles so a fifteen minute walk was no problem. I had a torch with me to light my way.

On the way home, I tripped on a pothole and fell over, landing heavily on my upper right arm and shoulder.

As I laid on the floor, my smartwatch fall detection kicked in and it offered to call the emergency services for me. I remember struggling to reach to it with and hit the “I’m OK button”, even though I clearly wasn’t OK.

With hindsight, I should have let my watch contact the emergency services but being a typical bloke, I initially thought I’d just be able to get up, dust myself off and walk home.

I tried to get up but couldn’t. The pain wasn’t that bad but I just couldn’t move my right arm. I laid there, hoping that a passerby would stop and help me. Luckily, even though it was after 23:30, it didn’t take long for a car to stop and I was aware of people talking to me, checking to see how I was. One of them was an off-duty police officer and he and his partner were very caring, they produced a tea-towel from their car to mop up the blood coming from my mouth. After my arm hit the floor, my head must have bounced off the ground as well as I had a grazed nose, a cut on my chin and I’d badly bitten my tongue.

While they looked after me, a police car which happened to be passing also stopped and they took over. They were very professional, first asking if I’d had a drink and then checking to find out what had happened as they were concerned there may have been a fight. They gave me a once over and after determining that I lived almost literally around the corner, they offered to give me a lift home which I very happily accepted.

My wife got quite a shock, to have someone knock on the door at 23:45, only to discover a couple of police officers and her husband! They immediately quashed her fears as they said that I wasn’t in any trouble but had had a fall. They suggested that they thought I might have broken my arm.

Once inside, my wife and daughter quickly decided to take me to A&E in Colchester and despite my protests, within a couple of minutes, we were on our way.

Luckily, the A&E department wasn’t that busy and it didn’t take long before I’d seen someone and been taken off for an x-ray. By this time, the pain had started to build and I was given strong pain killers.

The results of the x-ray came back and it was determined that I’d broken my humerus in “at least” four places in what is called a proximal humerus fracture. Because of the location of the break, I was told that I wouldn’t be put in a cast but instead given a collar and cuff sling to immobilise the arm and be called back to the fracture clinic in a few days to see what should be done next.

Here you can see the initial x-ray with the the four most obvious breaks highlighted.

I had a very uncomfortable few days – My pain killers were increased a couple of times until all I was suffering was a dull ache. I kept my arm immobilised and got very bored, very quickly.

My appointment at the fracture clinic came through quickly and the consultant started off by saying that I “probably” wouldn’t need surgery but he called for another x-ray and a CT scan of my shoulder to be sure.

The CT scan was done and I was called back a week later. This time, the consultant went into much more detail and after some discussion, he decided that I would need surgery to repair the damage. In particular, one piece of bone had moved from the back of the humerus and would stop movement. He said that as I’m relatively young and active, he really had no option but to operate. If I’d been a lot older then it would have been a different matter but without surgery, I’d probably end up with so little movement that my arm would be effectively unusable.

I asked how much damage there actually was and he started out pointing out the broken segments within my arm but stopped counting at eight and said “it’s just like a mush in there.”

The surgery was booked for the following week and went without any major hitch. I was on the operating table for about two hours which is a lot longer than originally intended because the bone fragments had already started to knit back together. The surgeon had to scrape those bits out before he could even start the repair process.

I had a metal plate fitted, along with three screws and eight pins to get all the fragments back in the correct places and held together. This metalwork will be in my arm forever because once the bone has grown back it fits the metalwork at microscopic level. You can’t apply enough torque to turn the screws without breaking the bone so they’re basically fused in.

It’s still very early days as I haven’t even had the thirty staples out yet which are holding the incision closed. My arm continually aches but I’m pleased to report that I’ve already started physio and have got more movement now than I had before the surgery.

This healing process isn’t going to be quick. I can’t drive and I can only use a keyboard one handed. I’ve been writing this article using voice recognition so I don’t have to do much typing.

One of the big issues I’m suffering from is lack of sleep. Since the fall, I’ve not slept continually for more than about forty minutes because I just can’t get comfortable. I find a position that’s relatively painless, nod off and then wake up again soon after. The medication I’m on for the pain causes a dry mouth and each time I wake up, my mouth is so dry that I can barely open it to pour some water in. I’m just catnapping whenever and wherever I can for a few minutes at a time.

I was told that when I’m all healed and this is all over, if I can raise my arm to shoulder level then it’ll be considered a success. I want more than that, I’m doing all the exercises I’ve been told in the hope that I can get better than what the surgeon predicts as ‘best case’.

As I progress through the healing process, I’ll post updates on Twitter.

I’m just bored though. At this stage, there’s not much I can do. I can play a bit of radio but my attention span isn’t very good and it soon frustrates me. I’m putting this down largely to the lack of sleep and am looking forward to the time when I’ll get a full night again, or even just a few hours uninterrupted sleep.

I suspect that going through security at airports will be challenging in the future as well.

Addendum (28/12/2019)

This arrived anonymously in the post today, I genuinely have no idea who sent it to me but if you’re reading this then thank you!
It gave me a much needed laugh.

Addendum 2 (31/12/2019)

The dressing and the staples were removed two weeks after surgery and now the long process of rehabilitation starts. My aim is to get as much mobility and strength back into my arm as possible.

Posted in Not amateur radio | Leave a comment

Rebuilding and raising my ADS-B receiver

Earlier this year I replaced my Hexbeam (with another Hexbeam) and I wrote about it on this site. There was a gap of a couple of weeks when I was between aerials and to take advantage of that, I temporarily moved my ADS-B receiver to a temporary stub mast, effectively raising it 7ft from the original height.

Although this was only a small increase in height, the difference in performance was very noticeable and it germinated a seed that I’d planted in my head some months earlier. I’d been trying to work out if I would benefit from mounting my ADS-B aerial on top of the Hexbeam and even whether it would be possible or not.

Clearly the answer to the first part this was a huge “yes” but the next part was whether I could attach the aerial to the Hexbeam. I contacted the aerial manufacturer who suggested I could fix the 40m centre support pole to the Hexbeam and mount the ADS-B aerial on that.

You’ll remember that when I replaced my Hexbeam, the one I put up included the 40m element so after changing the aerial, I could see what I’d need to do regarding the ADS-B receiver.

For the last few years, I’ve been using a FlightAware 26″ 1090 MHz aerial and I’ve been very satisfied with it. I wanted to buy a new one and started looking around. Unfortunately there were none available in Europe whatsoever and all the suppliers I contacted in the USA either weren’t prepared to ship to the UK or wanted ridiculously high carriage. I contacted FlightAware direct and explained my situation. They were happy to ship me an aerial which sadly got lost by the courier and so they arranged for their European partner, Jetvision to send me an aerial. That arrived in early October while I was on holiday in the Channel Islands.

I also ordered 10m of Messi & Paoloni coax. After poring through the specifications, I decided to go with Hyperflex 10 as I figured it would give me an acceptable level of loss and be suitably flexible to go around the rotator. Incredibly, this was also lost by the courier (a different one) and a second shipment was arranged which arrived within a day of the aerial, while I was on holiday.

I’d also decided to rebuild the entire receiver system in the box as well. I was going from a Raspberry Pi 3B+ to the newer Pi4 and wanted to replace the slightly bodged power arrangements I’d used previously with an official Raspberry Pi PoE HAT.

With everything ready to go, all I had to do was wait for the weather to be decent enough. I needed a combination of a few days without rain and then not too cold with no wind. This took longer than expected and it wasn’t until the 24th November that I was able to lower the mast and do all the work.

I fitted the new aerial to the top of my Hexbeam and routed the coax down to the receiver box. I then stripped everything out of the box and rebuilt the receiver with the Pi4 and new PoE system. I cut the coax to length, installed the N-Type connector and fitted everything back together before raising the mast back up. The whole process took around three hours.

Because my new Hexbeam is taller than the old one, my ADS-B aerial is even higher than I’d hoped for. It’s now 11ft higher than it was and so is 44ft (13.4 metres) above the ground which is quite a substantial increase. However I’ve introduced some loss into the system which didn’t exist before due to the coax run. I’ve calculated this to be around 0.7dB which I consider to be acceptable.

A few days after I did this work, I went out for my morning walk and it was a typical autumn morning. Very chilly and bright, with a beautiful, cloudless, clear blue sky so I just had to take a picture. You can clearly see the Jetvision aerial on top of the Hexbeam and the box the equipment is all mounted in on the side of the mast. If you look closely, you can also see an aircraft in the background, although you might need to click the picture to zoom in.

Hexbeam with ADS-B aerial

In practical terms, it’s relatively easy to work out how much difference this upgrade has made. Taking into account the raised aerial and the change from the Pi3 to the Pi4, I’m seeing approximately 50% more messages per day, an increase of around 20% in the number of aircraft per day and I can see from the coverage graph on the FlightAware statistics page that I’m now receiving signals from aircraft out to 250+ miles in all directions. At time of writing, my message rate/second peaked at just over 2,900 on the 11th December.

I’ve done extensive testing while transmitting on all bands with high power through the Hexbeam and the RF doesn’t affect my ADS-B receiver at all.

You can see the live feed from this receiver and the two others I am responsible for on this page which also contains other links such as graphs, statistics and daily heatmaps.

I feed my data to a number of providers and also to Essex Radar which is my own consolidated Virtual Radar Server.

For completeness, here’s a list of every piece of equipment used in my installation from top to bottom:

Jetvision aerial
5.5m of Messi & Paoloni Hyperflex 10 coaxial cable
N-type female to SMA pigtail
Bias-Tee injector
SMA to SMA pigtail
Airspy Mini
Raspberry Pi 4 Model B (2Gb RAM)
Raspberry Pi PoE HAT
30m CAT 6 cable
TP-Link TL-PoE150S PoE injector

Posted in ADS-B, Amateur radio, Construction, Raspberry Pi | Tagged , | 4 Comments

Building an MMDVM hotspot on a budget

I bought myself a new handheld at the Newark rally earlier this year, an Anytone AT-D878UV to use on DMR. When I went on holiday in October, I took a couple of copies of RadCom with me and in one of them there was a review of my handheld. The author mentioned that he’d used it through a hotspot and this got me thinking because although there’s a DMR repeater near me, I’d never played around or experimented with hotspots. In fact, I’d never even seen one!

I like learning about new things so I contacted the author of the review asking for recommendations about hotspots and he suggested the Zumspot as being a decent pre-built hotspot that’s easy to get going. I dutifully ordered one while I was away and it was waiting for me by the time I got home.

Setting it up was very straightforward and within a few minutes, I had it all up and running and working perfectly with my handheld. I quickly learned all about the different modes it can be used with and spent some time upgrading it to the latest version of the software and fine tuning it.

I decided that I’d like another hotspot to use with D-STAR as there are many reflectors not available through the local D-STAR repeater and I thought it might be interesting to listen to some of them.

Rather than buy another Zumspot I thought I’d try and buy all the parts needed to assemble one myself and see how cheaply I could do it.

There are lots of MMDVM modems available on eBay so I just picked one at random and ordered it. The one I chose wasn’t quite the cheapest but it was within a few pennies of the absolute cheapest. I paid £14.07 but I see that the same module from the same supplier has now dropped to £13.39.

It arrived quicker than expected as well – I ordered on the 1st November and it was delivered on the 13th November which I thought was pretty good considering it came from China. Unusually, the online tracking worked as well.

This is what I got:

MMDVM Hotspot Support P25 DMR YSF 32 bit ARM Processor for Raspberry Pi XY from eBay
MMDVM Hotspot Support P25 DMR YSF 32 bit ARM Processor for Raspberry Pi XY from eBay

The two sets of pins are for the GPIO header on a Raspberry Pi and the SMA aerial socket needs soldering to the board. The size is perfect for mounting on a Raspberry Pi Zero W and I had one spare so it only took a few minutes to solder the header and the socket in place and I quickly had a unit ready to go.

MMDVM Hotspot attached to a Raspberry Pi Zero
MMDVM Hotspot attached to the Raspberry Pi Zero

I wrote the SD card with a Pi-Star image, put it in the Pi and booted it. I’m not going to go into the details of how to write a card or configure Pi-Star as there are many places on the internet showing how to do this. The site by Toshen, KE0FHS is the best I’ve found for Pi-Star resources and you can visit it here. It took me about ten minutes to set everything up and reboot it.

A lot of hotspots come with little screens on them. In the limited time I’ve had the Zumspot, I really don’t look at the screen at all so I didn’t include one as part of my build.

This homebrew hotspot is working as well as the Zumspot. It doesn’t come in a fancy case, it doesn’t come with a screen but neither of those are important to me as I just want functionality.

Here’s a full breakdown of the cost:
MMDVM modem from eBay – £14.07
Raspberry Pi Zero W – £9.60
Raspberry Pi PSU – £8.00
16Gb SD card – £5.99

Total cost – £37.66

I could have built four of these for less than the cost of the Zumspot.

I’m not saying that people shouldn’t buy commercial hotspots but just wanted to demonstrate that it’s very easy to get the parts separately and assemble a fully working hotspot.

Posted in Amateur radio, Construction, D-STAR, DMR, Hotspot, How to ..., Raspberry Pi | 5 Comments