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SITE LAST UPDATED ON: Thursday, 12/03/2015 @ 01:37 UTC.

DVU37 - Output 439.4625 MHz - Input 430.4625 MHz.

GB7JB is funded solely by donations from its' users and supporters. There is no club or group to join and no annual membership fee. We rely totally on your good will.

The system is located in South Wiltshire, in IO81vc, co-sited with GB3JB, and provides coverage across South Wiltshire, South Somerset and North Dorset.

GB7JB is a 70 cm Digital voice repeater, based on DMR TDMA Mototrbo technology.
It provides TWO simultaneous channels. One is for local chatting, whilst the other is connected to the Regional Cluster / Network.

Wednesday, 10 December 2014


Well, the news we've all been waiting for ... the minimum of £1600 of donations have now been pledged, by 39 individuals, in 70 days.

To the 39, thank you all very much indeed.  GB7JB, will now definitely be going ahead.

However, that does not mean that those of you who have been holding back, to see if it will actually get going, can now forget all about it ... hi hi.

The £1600, gets GB7JB going, I will still need to find around an extra £300, between now and the end of February, to cover the increased all risks insurance cost and the cost of internet fees, associated with connecting the system to the Regional Cluster / Network, via the internet.

I have asked Peter, M0ACD, who acts as my Treasurer and who deals with all things financial, to set up a PayPal account and a Bank Account, so that all financial matters relating to GB7JB are kept totally separate from the GB3JB accounts.

The PayPal account is now available, but PLEASE make sure that you select the "send money to family or friends" or "donation" option, otherwise we have to pay fees, and don't get your full donated amount.

The e-mail address that you need to make the PayPal payment to, is:

With regard to the Bank account, it seems like it's going to be no simple feat to set it up, despite the fact that there is already an existing account for GB3JB, run by Peter M0ACD, at the same bank ... what a pa-lava.

Funny, our banking regulations seem to be designed to protect Banks from us, but NOT us from THEM !!!!!   But I digress .... hi hi.

I do not expect any payment this side of New Year, but do expect all pledges to be honoured by the end of January.

If, however, you wish to make your pledged donation, now, you can use the PayPal, link, to the left of this posting.

When making your donation, PLEASE also include a short message, in the box provided, indicating your Full Name, Callsign and e-mail address, so that we can link your donation payment to your earlier e-mailed pledge, or log it as an unexpected donation.

Between now and early February, I shall be organising the various other bits, batteries, inverter, duplexer, and the installation of the replacement antenna.

The existing antenna having been damaged by some rather large Raptors, that fly around the site, and use the tower / antenna radials as perches.  They've not been very kind to the radials .... The replacement antenna, does not have any radials .... hi hi.

So folks, thanks to all who have again shown their faith and trust in me.  It really is very much appreciated, and I hope you will get as much fun out of GB7JB, and the DMR TDMA technology, as I know I will.

Cheers & 73's
Dave, G3ZXX.

Tuesday, 25 November 2014

GB7JB UPDATE - 26th November 2014

Hi All,

For those of you who are still wondering if GB7JB is something that you would like to support, please take a look at the following animated .gif image.

This shows the predicted combined coverage, for mobile stations, of the 5 repeaters forming the DMR TDMA "Regional Cluster / Network", which you would of course be indirectly supporting, by helping to get GB7JB, on the air.

The 5 Repeaters are:  GB7AA, GB7BS, GB7DR, GB7SD, and of course GB7JB.  (You can click on the callsigns to visit the relevant ETCC pages).

It also shows the impact on the overall coverage, when GB7JBs' individual coverage, is removed.

You will note that GB7JB has a significant impact on the overall coverage.

From a technical standpoint, the DMR TDMA system offers a significant advantage.

This being that each repeater is actually TWO repeaters in ONE.

Thus users of GB7JB, will have two simultaneous channels, or slots, available to them.

One will be connected to the "Regional Cluster / Network", thus enabling users of GB7JB to work stations, who fall within the overall combined coverage area, no matter which repeater the other station or stations, are actually using.

The other channel, or slot, will enable you to have a "local natter" to stations within the individual coverage of GB7JB.  As shown below.

So, two repeaters for the price of one .....

And of course, NO background noise .....

As you will have noted, so far I have received donation pledges from 28 individuals, the value of which totals up to £1,125.

For GB7JB to go ahead, I need to secure pledges to the value of £1,600 as a minimum, by the 31st December.

If this value is reached, then I shall require the pledges to be honoured, during January 2015.

The £1,600 is to cover the cost of purchasing the Motorola Mototrbo Repeater, a secure 3G/4G internet router, and hopefully two additional 250AH batteries, to bolster the support capability at the site.  Although I note that the matching batteries, to those already on site, have recently gone up by almost £50 each !

I have personally already sourced and funded the antenna, feeder, duplexer, 24v to 13.8v regulator, and other sundries, etc.,

I do hope that you can see the benefits of supporting a 70cm DMR TDMA repeater in this area.

If you have any questions, please feel free to contact me, via e-mail.

Please send your donation pledge to:

** Remember to include your Full Name, Callsign and the amount pledged.

Cheers & 73's
Dave, G3ZXX

Thursday, 25 September 2014

GB7JB Funding - Updated 24th November 2014

Well OVER half way there ......

ONLY £605 to go and 5.3 weeks to do it in ......

GB7AA, GB7BS and GB7SD are already on the air;  GB7DR will be, within the next couple of weeks.

4 out of the 5 repeaters, making up the "Regional Network" are in place, don't let GB7JB be the missing link.

The 31st December IS the deadline, to get to £1600 of pledged donations.

I do NOT want any money, now.

We are looking for funding pledges, and we see the process panning out as, or very similar to, that set out below.

  • If between now and 31st December 2014, the pledges total up to the funds required, then I shall expect the pledges to be honoured by the end of January 2015 and the GB7JB project will move forward, very quickly.
  • If the pledged total reaches the required level, at any time before 31st December 2014, then I shall call in the pledges and move the project forward at that time.
  • If by 31st December 2014, the required level of funding (£1600) has not been pledged, then I shall cancel the GB7JB project, and return the NoV to Ofcom, since it will be clear that there is insufficient genuine support for the project to proceed. No one, up to that point in time, will have actually donated any money and we will not have to return any.

Cheers & 73's
Dave, G3ZXX.

Monday, 20 January 2014

GB7JB - Gets' it's NoV.

Hi All,

As you are all aware, on the 14th November I applied for an NoV to establish a 70cm DMR Digital Voice repeater, to be located at Willoughby Hedge, along side GB3JB.

On the 9th December ETCC, approved the application and passed it to Ofcom, with the recommendation to issue an NoV.

I can report that the NoV has been granted, in what as far as I'm concerned, must be a record time for a 70cm repeater.

In fact all three applications, for GB7BS, GB7SD and GB7JB, have been granted and cleared to go, today, 20th January 2014.

This very quick clearance does give us a slight problem in that all three applicants had been expecting the more normal inordinate amount of time to elapse, while MoD etc., considered the applications.

We will be co-ordinating our approaches to getting the repeaters operational, and the networking established.

I will provide more info regarding GB7JB, and the other systems, as and when available.

Cheers & 73's
Dave, G3ZXX.