Month: November 2015

Operating GB0SNB special event call from the Kelvedon Hatch SNB

On Saturday I operated from the Kelvedon Hatch Secret Nuclear Bunker near Ongar. The bunker is a large 3 level underground site, with a 50 meter mast on the roof. The bunker was active until 1994.

The bunker has a permanent special call sign GB0SNB and is open to the public as a museum.

Working with George M1GEO we completed some QSO on 5 MHz, 14 MHz and some VHF contact on 145 MHz.

You can read more about the bunker online, and if you’re local why not plan a visit. The current owner Mike Parish gives you a virtual video tour below.

The Icom 7100 provided HF and VHF. To the left is the TYT MD380 and right Icom E92



Operating is completed from the original home office radio room, although this equipment is on the back wall its only for show.


Here you can see George M1GEO tinkering with the IP and the co-located GB7KH DSTAR repeater.


Hytera MD785G review and first impressions.

After my last article on the TYT MD380 I decided it would be nice to get a DMR radio for the home / car use. I read quite a lot online and decided to select a radio that would support roaming. The Hytera MD785G fitted the bill, and is available in both a high and low power UHF or VHF version. I selected the UHF 45w version, and purchased the programming software and lead. The ability to load codeplugs is essential, as DMR is still very much a moving target, new repeaters are coming on all the time.

The Hytera MD785G is a tier II DMR radio, UHF 400 to 470 MHz, with a 1024 channel capacity. It can be programmed with up to 64 zones (16 channels in each zone)



Size 174 x 60 x 200 mm at 1.7 kg with colour LCD display.


RF power is adjustable depending on model  from 5 to 45w (high power version) or 5 – 25w (low power version). The 785G supports GPS although the amateur DMR networks does not support GPS location data at this time.

The radio has a BNC connector on the rear for your aerial, and SMA for GPS. The resolved audio is loud, crisp and clear and the radio looks and feels solidly built.



I couldn’t find any good quality pictures of the top, front and rear online so I took some myself. Here you can see the BNC connector for your aerial, heatsink, power lead (detachable) and SMA for the active GPS antenna.




UPDATE Jan 2016

The structure of the DMR network has changed substantially since I first wrote this article, and many of the codeplugs have become outdated. New codeplugs that reflect the FEB 16 structure can be found at GB7JG and GB7CL website.


At the time of writing some previous sites have outdated codeplugs (although links retained as they may be updated) Codeplugs online are often outdated G0HWC site.  Other codeplugs are available from codeplugcentral and  GB7DD.

Hytera MD785 CPS software is available at GB7DD

You can monitor live UK traffic for DMR online, and clicking on a callsign / repeater  will filter activity just for that call / repeater.

A list of all the UK DMR repeaters is available on the UK repeaters website.

Ham radio now filmed W2XAB John giving a great talk available to watch below on DMR. He also produced a guide to DMR in PDF free to download.


Operating portable from Cromer Norfolk

A long weekend away in Cromer, time to close up the static van for the winter and hopefully some time for /p. This time I wanted to try a 20m endfed wire, this ran from the tree at the back of the van into the ATU. I connected up another 20m wire and connected that to the earth of the ATU. The antenna seemed to work quite well on 7 MHz and would even load easily on 3.5 MHz (working as a 1/4 wave). I decided to try my luck and load the antenna on 1.9 MHz, as this weekend saw the RSGB club calls contest.

Despite doing a really good impression of a spark generator I did manage to work 20 stations around the UK. The best DX for the weekend was working into South America on JT65 on 3,5 MHz.

Also had a nice QSO with Peter G4VLC on 5.3665 MHz Olivia. Once again goes to show 10p of bell wire may not make the best antenna in the world, but it sure beats the £149.99 Chav 1.