Welcome to the GB3SH webpage
April 12 2000
GB3SH, the Southampton and South Hampshire 2m repeater has finally happened, 20 years too late according to some, but now its here!
The second in a family of repeaters serving the area, GB3SH was co-sited with GB3EA, the repeaters shared the same co-linear antenna which was mounted 70 Ft. AGL. Its output frequency is on one of the recently created half channels 145.6625, with the input the UK standard 600Khz below, access is by 1750 tone-burst or a ctcss tone of 71.9.
The repeater is a modified Yaesu unit originally meant for commercial VHF use and uses *NEW* WACOM 8" cavities for single antenna working. The licence allows 12.5 watts o/p power and the receiver is very sensitive, so it hears further than it transmits!
Inital reports are good, although some users are reporting sproggies from "road-side equipment" are causing localised dead spots in the city of Southampton and in some other built-up areas.
The problem with sprogies is growing, the suspects are cable tv units that have been interfered with (domestic premises), and data packet users (commercial).
Due to the extream weather (heat) the squelch has locked open (either that or the jammers are back) so until extra cooling is fitted SH will operate on a cool days only sked. A site move to an air-con'd field room is happening soon too, so the problem should not persist for too long (the dx cluster links elseware are also down for similar reasons, we Brit's just don't do with hot weather).
Our site is gone, so the keeper is relocating it to his home pro-tem, however GB3EA cannot be moved, RSGB won't give a reason, just it cannot.
A potential new site, more in 2004!
Further updates as they happen.
Moved to new site in central Southampton, with a short co-linear and reduced erp, what an improvement! Further better antenna and full erp soon!
2006 technical update from Andy G4MYS (keeper):
GB3SH uses a 10Watt Yaesu FTR 2410B Repeater, with modfied GB3US mk 1 control logic, this has been altered to allow CTCSS access on 71.9Hz, in addtion to 1750Hz tone burst and carrier reaccess. CTCSS tone is on transmitted except during beaconing, this allows for silent monitoring.
The GB3US mark 1 logic is probadly the easyest logic to use, and does not require an inteligence test to work out how to get in.
However a new machine is in the wings and that will use the so called "HOZ logic" (you will note that GB3ET has logic which works in a simular way) more about that when we introduce the new machine, and logic.
G3SH uses a set of WAYCOM 8" 3 ft high duplexers to allow us to combine the transmitter and receiver signals for common aerial working, indeed a further "diplexer" adds in the Signal from GB3SU (the on site UHF repeater) to the coaxial cable for its run to the aerial which is a dual band colinear some 53 Metres above the ground, thats 173 feet in English! Making it possably the lowest in the country.
A map of the coverage can be seen at WWW.RSGB.Org.UK follow the "Repeater" and "Repeater Maps" links for information.
However the site is exceptionally good with coverage well across the South Hampshire area and well into Dorset and South Wiltshire, covering over 50miles of Southern Englands Car Parks the M3 and the M27 !
But its central city location with city QRM and a nearby, but Lower tower block has one of those pager units on it which pummel any 145Mhz receiver within 50 miles, or so it seems. This is taken out by an addtional 1Mhz wide 145Mhz band pass filter with an attenuation of some 60dB at 153Mhz.
The current machine and its aerial runs about 15 Watts ERP.
73's De G1DQX Niel, GB3SH Webpage Admin.
P.S. New members always welcome, we need your money ! (Running repeater's is not cheap !)