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.

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.

Here are a few snap-shots from the live video feed which you can watch regularly on our live video link here.

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.

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

Here is a short video to show you how bad the interference is when a weak signal is accessing GB3WE and metal objects are allowed to rub on the guy wires

GB3WE View Of Glastonbury Tor Rising Through The Clouds

GB7WB new blades and tail 14 Jan 2011

This left the blades facing the wind, which caused them to spin at thousands of RPM until they were all broken off. This is a disaster for our repeaters.

It is worth noting that our modified oil-filled heater 24v dumpload worked perfectly day after day and saved our expensive battery sets from over voltage charging and burning out.
Other repeaters running from wind turbine power not so far away lost their dumpload, which in turn destroyed their battery sets. They also lost their mast and antenna. It was a real nightmare for us all!

We have currently turned off the repeaters to conserve the power in the batteries.

A new tail and set of blades will have to be bought and fitted asap so that the repeaters can be activated again.

Click on the play button below to watch a video of what is left of our turbine.

GB3WB Globe Photo Galleries
Have a look at our 1st photo gallery here                Have a look at our 2nd photo gallery here

Gb3wb photo gallery. Click on the pic to view

Gb3wb photo gallery 2. Click on the pic to view

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.

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.

Due to the terrible wideband local oscillator in the cheap wireless doorbells we are finding more and more cases of transmissions appearing on frequencies where they shouldn’t be. In fact it turns out that any 70cm signal can easily be mixed by the doorbell and the original signal can now be found somewhere else in the band as well. 
 

GB7WB October Sunset Looking Towards Dunkery Beacon

GB7WB October Sunset

GB3WB with 747 just above the mast

GB3WB with Boeing 747 a few hundred feet above the mast breaking through the clouds.

GB3WB 500w Oil Filled Dump Load

GB3WB Original Wind Turbine Sprayed. Now that the wind turbine blades have been silenced by the modifications found here we have opted for a blue camo finish in place of the original dark green option.