No NOV in 2014

Well the powers that be have now finished for the year, ending any expectation of GB7MB getting on air  before the new year. So the repeater will have to remain on the test bench a little longer.

So it is time to wish all our members and visitors a happy Christmas, and a good new year. We hope everyone enjoys there holiday.

GB7MB Repeater ordered

Today, The repeater – a Motorola MotoTRBO DR3000 UHF repeater was ordered from Our Good friends at Ham DMR who gave us the best deal. Thankyou Adam.   HamDMR’s website is at at

The GB7MB Group are watching the ETCC website for any movement regarding the license for GB7MB, though at the time or writing (13:21 – Friday 12th Dec 2014) no movement is expected before next week. Any and all updates will appear here first.

Get some FPP on a DM4600 ?

prgm radio
Yes – FPP or ‘ Front Panel Programming ‘ is often seen in Amateur circles, generally in conversations about commercial or PMR gear. As upper-teir commercial gear is now almost all menu  driven, Amateurs often debate on how much control they have over things like frequency, CTCSS, power or whatever, without having to plug a laptop into the set to tweak it, which,  lets be fair,  could be a real pain. There is no real need for commercial users to be able to change these settings, it may even breach some laws somewhere, so consequently,  very little commercial kit has such abilities, much to the chagrin of some Amateurs.

The popular Motorola MotoTRBO DM4600  and the Dp4800  do already have some FPP features already, but hardly anyone bothers to enable it. You can’t change frequency, Talkgroup or CTCSS (yet) but it still adds a useful few tweaks to your inventory for that odd time you need them. Here’s how to do it.
In the Motorols CPS   in the global settings, up top, in the right-hand pane find Front Programming Password.

 dealer mode 22

set Mode to Dealer – and enter a password – obviously its not the Crown Jewels so i just made mine all 1′ as you see …   by the way – you cant have ‘No password’ either Then, remembering your password – save your codeplug back to your set. Now in the Menu’s, under utilities, you will see a new sub menu “Program Radio”

prgm radio

Now you click that and it will request your password.. well, numbers anyway..


we can edit some channels now

edit ch

Now you have a selection of new menu’s you never had before – here we are changing colour code —

col code

and slot


even rename them, or copy them into another zone..

ch name


And whilst you’re at it..  treat yourself to a IMPRES DTMF mic – RMN5127C and you’ll be able to switch the display to  rssi (signal strength) too – and you’ll forget its not an Amateur rig – because with 1000 channels – you might as well have a VFO -is Amateur radio moving finally into the 21st century ?  here’s hoping..


All work, text and images © GB7MB

Decode DMR with an SDR !

rtl usbsdr sharp running

So – you’ve bit the big one and bought a USB SDR – but how to decode some digital then ?
I’m no expert, but here’s a brief introduction to getting started SDR’ing – and maybe – just maybe it’ll work for you too.

I’ve put a so239 on a short flylead to this RT810T – yes its a digital TV stick, but as i would rather eat hammers than watch TV –  a reasonable 50Ω connection was deemed a necessity.. the original MCX connector was totally pointless, but you may have a Belling-Lee – either way, thats exactly 100% better than the sorry little MCX was.

When you plug in you USB SDR – Windows will prompt you to install some drivers – don’t bother – you’ll be replacing them in a few minutes anyway.
You’ll first need to install the dot net framework here   but you probably have it already.
Then you need to download the main software,  its called SDR#  get it here  – there are others.. but i prefer this one. it seems the most popular one anyway.
The main SDR setup file will be called so you know what you’re looking for in your downloads folder.

Double-click and you’ll see another folder – click in there and run the  install.bat file

sdr batch file

it will then go away and install SDR sharp – it will create a folder on your hard drive called c:/sdrsharp

sdr folder1

sdr zadig 1
then Zadig will start,  although  it will look a little blank, like it does below –

so go to Options  – then List All devices then it looks better – so now from the drop-down, select ” Bulk In Interface 0

Then click Install Driver – you can see here that i already have it installed – as in this pic it offers to reinstall – so i didn’t need to.
You will get a “This Publisher can not be verified”   dialogue box –  But click “Install this driver anyway”

make sure you’re not installing another devices USB driver –   i made an error and i lost my mouse – it’s a real pain in the arse trying to navigate Windows with a keyboard..


Now start SDR Sharp – go to the Cog icon – from the drop-down select your SDR – as you can see here – i have a generic RTL2832 dongle.
I always slide th RF gain fully up (the slider above where it says Frequency Corerection) and usually enable both AGC’s as these bump up the gain quiite a bit when listening for weak signals.
Now lets  TEST IT !


The left-hand menu drawer need some tweaking now, oh what joy..
first we need to check its working – unless you’ve selected the wrong Source – it should fire up ok. first thing, lets get it to hear a noise.
Lets select the output device – here i’m, using Windows direct sound.  You might, well ok, almost definately will need to experiment here to find the correct one.
so press the START triangle and try to see if you get noise. You will need to press stop to change devices, and to restart to check it again. when it makes noise (make sure the graphic display is doing something – and make sure that the squelch is OFF and “filter audio”  is unticked too.  If its not doing stuff- read up here

sound 1

Now You have it all working – its time to change it !
download This  VB Cable     Why ?
if you’re hoping to decode DMR – or p25 or whatever – SDR sharp doesn’t do it … so you have to get it to pass its audio to another program… this VB cable does that  (by the way, turn off any special effects on your soundcard if you have them on too) You will have to reboot after installing VB cable – there’s no interface to the program really – its largely invisible, and as its a very ‘light’ program, which is just as well really,  it comes in handy when you’re recording the audio onto the same PC too etc.


Now whan you start your SDR – you have a new option -CABLE – for decoding DMR this is where SDR  needs to be set,  so it can pipe its raw FM audio into a decoder.
Now you need a decoder,  here is one  DsD-Plus  and here is the discussion and HowTo for DSD+  but basically,  just unzip file into a folder and double click on DSDPlus.EXE and you should get a window open up, and you can then tune around for a DMR signal.. There is further and more in-depth reading on these links, there is much to tweak so I will leave it up to you …


All work, text and images © GB7MB

GB7MB’s NOV could be soon

Maybe it will be before Christmas even … enjoy the retro pic i made at brewtime.. i kind of like it – i’m a TV nostalgia fan, so this may look similar to anyone else who used to watcb IBA Trade test transmissions and the BBC Transmitter Information programmes that were on TV .. before the programmes started..   Imagine that – there were no programs on the TV – ahh how blissful that would be.. or maybe i just need to get out more..


All work, text and images © GB7MB

coming soon

NEWS: GB7MB Repeater: Update –

The GB7MB repeater group have started looking to purchase the required UHF Motorola DR3000 repeater. Sources indicate that GB7MB may indeed appear (in some form) on the 70cms band over the Christmas period.

When the license arrives, please do not expect GB7MB to be on-air immediately, nor available 24/7,  or with the full coverage footprint,  or with full DMR-MARC access,  as there will, of course be a testing period.

Requests to all Ham-friendly Motorola dealers for the purchase of the repeater, will be posted on the usual Facebook groups, most notably the UK Digital Amateurs and the GB7MB Repeater  Facebook pages.

The idea is to hold a ‘reverse auction’ by asking sellers to submit their best (lowest price) offer to us, via private message, and once the prospective offers are in, the GB7MB Repeater Group will take their decision,  and of course, all relevant news and info will appear here first 🙂
Watch this space.


All work, text and images © GB7MB

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