GB3WX is a 6m/10m Cross-band, Simplex, Repeater/Beacon system.
Yes, I know that sounds confusing. It is quite unique.
The system was conceived to provide a dual-band beacon, with the capability of simultaneously transmitting from a common unity gain vertically polarised antenna, with the same 25 watts ERP, and with the additional capability of providing the ability to actually communicate through it, rather than just listening to it, beacon.
The fact that the system has the commonality across the two bands, provides a unique opportunity to make direct and simultaneous comparisons between 10m and 6m propagation.
The system has been on air, on several occasions in the past, but only for very brief test periods, during it's early development.
The system, has taken quite some time to develop, with long delays being attributable to the technical requirements imposed by Ofcom, and the very sad loss of Clem, G3UGR, who was the technical guru.
The replacement of the original site mast, with a tower, also forced a re-think on the planned antenna, which was no longer a feasible option, with the tower.
The replacement of the original site mast, with a tower, also forced a re-think on the planned antenna, which was no longer a feasible option, with the tower.
Fortunately, when all was looking lost, and I was seriously considering consigning the project to the bin, John, G4RDC, stepped in to take on the final development of the project.
This has not been easy or straight forward, with regard to the additional hardware and custom software that has had to be written, to support the existing controller, and thus enable the system to comply with the Ofcom requirements.
There have also been issues with the two Alinco DX-70th radio's, with PA drivers and PA's going pop !
However, the project has made significant progress over the last 10 months, thanks to John, and the system is now undergoing bench testing.
At the time of writing, 28th March 2015, I anticipated being able to install the antenna system over the next month, and to then commence testing and commissioning as soon as is possible.
However, the basic system is as follows:
- FM, Analogue Voice - 77Hz ctcss required.
- 2 x Alinco DX-70th Transceivers.
- 10m - Output 29.210 Mhz - Input 50.520 Mhz.
- 6m - Output 50.520 Mhz - Input 29.210 Mhz.
- Antenna: Dual band "Slim-Jim", with split fed system - G3ZXX
- Custom 6m/10m Filters designed and manufactured by Cross Country Wireless.
- Base Controller - NHRC-7
- Refurbished HP laptop - G8CYV.
- Additional Hardware and Software - G4RDC
Full details of the final operational characteristics, along with a system schematic and operational flow diagram, will be provided later.
A computer predicted coverage map, generated by ETCC, can be viewed, by selecting the following links.
Of course, the predictions, only relate to localised ground wave coverage.
A computer predicted coverage map, generated by ETCC, can be viewed, by selecting the following links.
This page last updated: 30th March 2015 @ 2100 UTC.
