Updated 29Aug21 - The Story Continues……. Here we are MB7ISC Mark 6. The Latest iteration of the Analogue Simplex Gateway in Stirling, IO86AC.

 I am really thrilled about being able to bring to the local area my Analogue Simplex Gateway.

Many years ago I used to operate a Gateway station from my old QTH in Somerset.

15 Years later, A lots changed. I don't seem to remember the regulations being quite such a brain twister, then again. Then again my memory may not be accurate.

In short I’ve learnt a lot and rather quickly so this station has been redesigned and redeveloped now four times.

Station Mark 1

Was using a Raspberry Pi, Software was OpenRepeater which proved to be really easy to configure and the Radio was my old faithful Icom IC-706MKIIG. True Radio wise a little overkill but we use what we have? And it was connected via a SignaLink USB Interface and COS & PTT was done via the Raspberry Pi GPIO pins. Nice clean simple.

Station Mark 2 

This was sadly a case of desperation turned out after 15+ years in storage my IC-706 had fallen rather Ill. Although it all seemed ok, Turns out the FM stage was massively faulty and doing all sorts of nasty things. So a rummage in the draws to see what else I had turned up my Wouxun KG-UV6D Handheld after some Googling I came across inspiration in the form a YouTube Video by KC3KPC 

Baofeng UV-5R Mod for Allstar & IRLP Nodes (Ham Radio) - Have a watch!

My modification varied a little from his design, I actually tapped into the Green LED (Receive LED) signal and am using that as my COS line.

I repurposed the SignaLink USB interface box and fingers crossed. It worked!

 Station Mark 3

For the Audio path - Well Mark 1 and 2 of MB7ISC was overkill and I had used a SignaLink USB interface box (initially purchased for my IC-706 which sadly has died). However with Mark 3 of MB7ISC now that I'd made the decision to use AllStarLink instead of OpenRepeater I needed to improve my soldering skills and take a different approach. 

This time I went for the method recommended on the AllStarLink Website and modified a CM108 Soundcard Dongle. I'd forgotten how fiddly working with surface mount components was, But after much careful work my new sound interface was ready.

The only problem I experienced is a really annoying buzzing being introduced to the TX Audio with the CM108, I'm confused as to why this was as everything is on a common earth but, it happened. However the quick addition of a USB Ground Isolator (thank you Amazon Prime) and the issue was resolved.

All of this is then linked up to a Raspberry Pi Model 3 with a 16GB Micro SD card onto which I installed the HamVoip version of the AllStarLink Software.

Once all of this was done we get to the last piece of the puzzle, What do we do with our new gateway to get the most out of it. For this I give full credit to Oscar 2E1HWE who got in contact with me when my NOV Application first appeared on the RSGB ETCC UKRepeaters website.

Oscar told me all about a network called FreeSTAR. A network that seemed to be a miracle in design in that they had not only a huge network of Simplex Gateways, but also repeaters and even more impressively they had 'bridged the gap' between many of the different digital communication systems now in use with Amateur Radio and so had links out to DMR, NXDN and more (see the FreeSTAR website)

So on 14th August 2021 MB7ISC officially joined the FreeSTAR network.!

Much to my surprise there was a popup net hosted by Bruce M0UKB that evening and it was fantastic fun, so many stations connecting across the globe it was wonderful. 

Station Mark 4

So now I had a successful, operational gateway. But like all true geeks, I never leave things alone when I should…. Afterall Technology is meant to be played with.

Changing Radio – The Wouxun was working well, however my father dug out his old Alinco DR-610 which he no longer used and he wondered if it would be of any use to me.

Back to Google we go to get the Service Manuals for the 610. At first I was really hopeful that other than making a new lead it would be Plug and Play. Actually, it almost was, The only difficulty was how to get a Squelch Signal output.

I eventually decided to take the radio apart and get at the CPU board that sits behind the Removable Front Control Panel and the main radio boards. On this board the CPU chip has two outputs for Squelch – Active Low type one for the Left Side and one for the Right Side. Some delicate soldering and I had my COS signal line. I will admit it’s not perfect and I’ll have to probably amend it at some point but it’s working. So Alinco DR-610 now runs the 2m port. 

 Station Mark 5

We all know the dangers – Once you start rummaging in the shack. You find all sorts.

Well that happened to me!! Or rather my Father GM0WUP – Along with the DR-610 he came across a DR-M06 and had the bright idea to suggest I add a 6m port to the gateway.

Having just installed the DR-610 I didn't see any issues, I contacted the RSGB ETCC and they indicated an NoV would not be an issue – so application made I turned to building a second Raspberry Pi CM108 interface system to add the additional port.

One slight roadblock – The DR-M06 had CTCSS ENCODE, But not DECODE.

Quick appeal for help on Facebook was made and I got a recommendation for a company called CSTech.co.uk who made a CTCSS Decoder kit. Eureka! We have a solution. The (completed kit – Yes I cheated) arrived very quickly and after checking the Service Manual I found the pin for the Official CTCSS decoder and linked this new module into that. It Works!

So now we have Two Ports but the idea of keeping both gateways on a little shelf doesn’t work anymore – It’s going to need a better home.

Station Mark 6

Wow Mark 6 and it’s only been just about four weeks since I build Mark 1!, This time metal cabinet was sourced in order to house all this equipment in a nice way that would do the job whilst keeping all the equipment safe.

But I noticed the Wouxun that I’d used for Mark 2 was looking lonely on my desk…. It’s a Dual Band 2m and 4m. Why not build it back in, After all I already have a CM108 modified for it, the appropriate cables made and I’d modified it to give the COS output.

Back to the ETCC I go…. NoV Application for 4m Gateway – Obviously it’s Attended Ops only but I can work with that.

So the biggest build to date got started and took about 5 full days to build it all into it’s new home, Antennas installed into my Roof space. A total of 4 Raspberry Pi’s installed, One for each radio port and one as a Master Controller.

The Emergency Shutdown & Remote Kill system also got upgraded this time using an Arduino Mega & Arduino Yun Shield and a nice Nextion Display panel to give me a nice front panel Status Display for all the equipment inside the cabinet.

So there we have it, the quick story of my gateway (So Far).

Now online and Active on;

• 145.2875MHz - CTCSS 103.5
• 50.5400MHz – CTCSS 103.5
• 70.3875MHz – CTCSS 103.5 (First Activation due 1^st September)
• Echolink Node Number 459689
• AllStar Node number 552480

A Big thank you must be given to the following, without their assistance, support and guidance this Gateway would not exist.

• Steve at RSGB ETCC for helping me through all the NoV applications.
• Oscar 2E1HWE & Bruce M0UKB for reaching out and getting me to join FreeSTAR
• Shane M0VUB For answering my questions about DMR and System X
• William GM0WUP (aka Dad) for the Alinco Radios & the not insignificant financial backing to get this running.
• My Wife (Helen) who if it wasn’t for her support and encouragement getting me to develop my skills and ideas. I wouldn’t do a fraction of the things I do.