gb3wb

Dual Tower Configuration For GB3WE GB3WB GB7WB

Since our tower was so badly damaged in the high winds we have worked hard to split our three repeaters antennas over our two short masts. GB7WB’s UHF 8-Stack is on our damaged main tower along with GB3WE’s RX VHF folded dipole. A spare 2.4GHz Tonna beam has been fitted as well.
GB3WB’s UHF 4-Stack is on our old turbine tower along with GB3WE’s TX VHF folded dipole. Our main 2.4GHz Tonna beam is also fitted to this tower.

To keep GB7WB on the air we have recovered as much of our damaged tower as possible and fitted its UHF 8-Stack to it.

Also we are using G4KLX’s split repeater software to enable us to use two separate receivers to provide site diversity.
The second receiver is in Worle to provide some additional receive capability.
Jonathan’s software automatically selects the best GMSK data from which ever receiver provides the best bit error rate.
Hopefully this will make up for the low height of the GB7WB 8-Stack.

On Sunday Morning 29th April 2012 our main tower suffered massive damage in the high winds.
At 5.22 am the lower part of the latice tower folded which caused the whole tower to fall into a nearby tree.
Amazingly not a single antenna or feeder was damaged and even the wind turbine and blades are in perfect working order.

In order to keep all of our repeaters on the air we have moved GB3WE’s folded dipole onto our small wind turbine mast. This mast holds the GB3WB 4-Stack already, so its coverage is unaffected.

To keep GB7WB on air we have had to temporarily fit a colinear to the very short remains of the damaged tower, so it is practically at ground level. Obviously coverage will be well reduced, but at least GB7WB is still on the air.

It was a very big and dangerous job to get the whole tower and turbine out of the tree. But to make the area as safe as possible as quickly as possible we have worked on the site more or less night and day for three days in some terrible weather conditions.

Here are a selection of photos of the damaged tower.

GB3WB has a new antenna. To overcome the problem of our original collinear’s high angle of radiation we have replace it with a UHF 4-Stack.

GB7WB Fan Control Thermostat Modified & Fitted.
The thermostat we had only had a ‘normally-closed’ contact and we needed a ‘normally-open’ contact to put the 24v fans on when ever the repeaters got too hot.
With three FX5000 repeaters stacked on top of each other, with their six combined crystal ovens and three power amplifiers etc you would be surprised just how hot they get!

A grub-screw was removed which was fitted to provide a rest for the center contact of the bi-metalic strip. A small screw with a solder-tag and wire was used to replace the grub-screw and the wire was attached to the spare solder post.

Now we have a single-pole, double-throw set of contacts and the fan switches on when the temperature rises.

GB3IE Dual-Mode D-Star GMSK & FM FX5000 Repeater

The Weston Repater Group recently completed a new dual-mode D-Star GMSK ircDDB & FM repeater for Plymouth. GB3IE is now on test in Plymouth, and will hopefully be in full dual-mode service very soon when its new NoV arrives.

GB3WE GB7WB GB3WB FX5000's

All of our FM analogue and D-Star GMSK DV-RPTR repeaters are now using FX5000 base-stations.

GB3WE GMSK D-Star Repeater Using DV-RPTR Modem
Audio control board details

GB7WB & GB3WB Both Using DV-RPTR Modems For GMSK D-Star.
Both of our D-Star repeaters have now moved over to DV-RPTR modems and are controlled by Jonathan Naylor’s latest beta software.
Get more details of the DV-RPTR modems here: http://www.dvrptr.de/
Find out about Jonathan’s G4KLX repeater software here: http://db0fhn.efi.fh-nuernberg.de/~g4klx/
Both repeaters are operating better than they ever have and don’t suffer from any problems.

While using either GB7WB or GB3WE Use Your DTMF Keypad To Connect D-Star Reflectors …

The available commands are:

# for unlinking
0 or 00 to trigger the info message
*1C or *01C or *001C to link to REF001C
1A or 01A or 001A to link to XRF001A
D5B or D502 to link to DCS005B

GB3WE GB3WB GB7WB New Configuration. GB3WE & GB7WB are ircDDB STARnet Digital Group Calling enabled D-Star repeaters.

GB3WE is the top mounted dual-mode VHF FX5000 D-Star GMSK/FM repeater.
GB7WB is mounted in the middle and is a UHF FX5000 D-Star GMSK Node.
GB3WB is mounted at the bottom and is a UHF Key Repeater for FM.

GB3WE and GB7WB FX5000 Repeaters. GB3WE at the top in brown is our VHF 2m dual-mode D-Star (GMSK) and FM repeater. Underneath is GB7WB, our UHF 70cm D-Star (GMSK) repeater.

GB7WB FX5000 UHF D-STAR GMSK Repeater

GB7WB Modifications to FX5000 Transmitter For D-Star Operation.

To modify an FX5000 VHF or UHF for D-Star GMSK operation simply add a 47nF capacitor across C493 (22nF) which is next to IC403 (TL072) in the transmitter driver module.
Then remove C536 (10uF) which is next to IC504 (LM324)

No modifications are necessary to the receiver module.