GB3ST – RB09
433.2250 MHz, FM Analogue Repeater
Location: Stoke on Trent.
|LOCATION||STOKE ON TRENT|
|LAT/LONG||53.036446 / -1.913464|
The GB3ST repeater became operational from its original site in August 1976, when, after what was then the Home Office, issued a license for GB3ST along with the first major batch of 70cm UHF repeaters here in the UK. The repeater has been operational from its present site since 1996 sharing its location with two other repeaters, GB3VT on 2 metres and GB3SE on 23cm.
From 1976 and during the past 32 years, the repeater has continued to be operational on RB02. However, due to an ever-increasing level of interference caused to the repeater’s receiver by the use of Low Power Devices (LPD) and Short Range Devices (SRD) that have now adopted the 70cm band as their home and because of this, the need to vacate RB02 and apply for a frequency change was requested. From the beginning of 2009 the repeater now operates on its new channel of RB09. This unfortunate, but never the less necessary change of frequency will take the receive frequency of GB3ST outside that of the current SRD and LPD frequency allocation within our 70cm band and thus hopefully stop any future occurrences of such interference problems.
GB3ST transmits on 433.225 MHz and receives on 434.825 MHz. Both the transmitter and receiver use full encode and decode Continuous Tone Coded Squelch System at a frequency of 103.5 Hz. To fully access the repeater and obtain full talkthrough facility, either CTCSS of 103.5 Hz or a 1750 Hz tone burst is required, followed by three seconds of good audio.
The Transmitter, Receiver and CMOS repeater control logic are all-purpose designed and homebuilt, the equipment includes several special features.
The Transmitter in use today, is basically the original transmitter as built back in 1976, however, over the years it has experienced several re-builds and modifications, including when in the early 1980’s the repeater was struck by lightning. On that occasion the transmitter was severely damaged and the “burn / weld” marks on the metal case are still visible today.
The Receiver now in use is the mark 3. The original receiver used valve technology and believe it or not, it actually worked very well. The mark 2 was a modified commercial and in some aspects was not as good as the valve mark 1. The present mark 3 receiver has now been in use since 1996, it is specifically designed and totally home built.
The Repeater Control Logic uses C-MOS technology and is also in-house designed and built, and the timeout is currently set at 4 minutes.
GB3ST uses a total of four cavities, two each in both the receiver and transmitter paths.
The repeater delivers its full, as licensed, 25 watts effective radiated power from a close spaced two colinear aerial system located at 10 metres above ground level.
REQUEST FOR HELP!
Searching through some papers Geoff, G8DZJ, came across a couple of photographs taken at Repeater Group meeting back in 1978. After pouring over it for a few hours and a bit of head scratching Geoff has identified a number of the faces but not all. Do you recognise anybody? Just for a bit of fun, between us, can we see how many we can recognise?
It amazes me how some have changed so much and others so little!!
Any way answers please, in an envelope – sorry e-mail to email@example.com.
Just for a bit more fun does anyone out there have any similar photographs from other meetings or get togethers?
No babies on rugs please. E-mail them to the address above and we’ll add them to the web site, or if you can’t e-mail them bring them to the rallies.
Remember this is just for fun.