It’s been about eleven months since we made the move from Woofferton to the new Hill Top House site on Clee Hill for GB3VM and nine months since we moved GB7VO from G8BPN’s Hill House to Clee Hill.
GB3VM Feeder Issues
We are pleased to announce that following a three or four month period of unusual oddities on GB3VM we have resolved the situation. Before Christmas 2021 we had noticed that there appeared to be many “dead keys” where the repeater would be set to TX but with no following traffic. In addition, we had noticed wandering carriers on the input 145.0125 MHz that actually didn’t force the unit into transmit mod, presumably because there was not 103.5 Hz CTCSS tone on-board. The confusion was also fuelled by the activities, nay, antics of our resident squeaker from Astwood Bank in Redditch who had been for the last nine months been playing music over the repeater.
Many tracks by George Formby had been aired along with Mandy Miller’s “Nellie the Elephant”. What had changed as that he was neither no longer squeaking nor butting in to other running QSO’s : so a small bonus. We are pleased to report he went away just before Xmas so we have had some respite.
G4OYX had been swapping out various bits of the system and changed the year-old Yaesu DR2 unit to a newly- acquired DR2 that Ken Lancaster, a friend of the group in Birdwell, Barnsley had bought for us. Sorry to say no change so on a decent day in February Ian, G8PWE and Dave, G4OYX attended site and were able to completely examine the system. Ian brought along a complete duplexer crate that had previously been a lockdown repeater for the Black Country. He had retuned it to the VM frequencies. It was fortunate he brought it as with that and a new circulator the performance to Test Load was excellent and no de-sense was noted. We connected up to the antenna and noted that the VSWR was excellent and that local stations could indeed make a QSO but low power stations or those at a distance for example, Les 2E0LRV in Redditch on 5 Watts could not make the trip. Ian suggested that we key up the repeater TX using the front panel mic socket with the PTT on the mic and connect through the system to the duplexed antenna. Rather than using the repeater’s RX we substituted a separate RX on the RX port on the duplexer, We had the FTM-400 on site and its mic did the PTT on the repeater and its RX the listening check. The result was amazing as when the TX was keyed the RX burst into life with a S9+ noise level. Going to test load all was quiet. Reconnection to antenna and the noise was back. It was the RF from the DR2 TX with CTCSS that were triggering the RX in the same DR2! A replacement RG214 coax feed to a spare antenna outside resulted in normal, quiet operation. Inspection of the regular feeder showed it to be Times Microwave LMR-400 – real high quality stuff… in theory. The construction is a copper- plated, aluminium centre core and foam dielectric that has an aluminium foil for screening then a nickel-plated braid and a PVC heavy-duty jacket. Ian recalled reading that this cable is not any good long-term, for common RX-TX combined use as the TX power throughput causes small voltages to be induced in the dissimilar metals Al and Ni on the screening. It looks like it lasted for about nine months before becoming a problem. RG214 is OK as it is double silver plated copper braids so no dissimilar metals. Andrew or similar hardline is fine as it is just all copper. LMR-400 is superb for low loss on TX and low-loss on RX but not at the same time! During the fault finding on the regular system we had noted that our normal service TDK circulator, when moved, caused crackling on the output. Close examination revealed pair of dry solder joints bonding the two boxes of the assembly. It re-soldered a treat… with a 65 W Henley soldering iron from the 1960’s. The opportunity was taken to treat the rusting tin-plate tuning box covers on the VM duplexer with Kurust followed by a final coat of Humbrol Red No.19 enamel paint. Ian and Dave left the repeater off for a few days and following a break in the winter weather Phil, G4HQB and G4OYX visited site and changed the LMR- 400 for a brand new run of RG214.
In mid-March Ian and Dave again attended site and checked the re-tune of the original VM duplexer and reinstated the TDK circulator. Connection to the DR2 and the antenna showed all to be now normal. The outgoing VSWR to VM antenna is 1.12 :1 and 11 Watts output. The TX loss across the duplexer is 2.2dB and there is 3.1 dB on the RX path, this is quite normal The squelch level is about -117 dB.
Indeed, since the repairs we have heard HARS Club member on holiday, Keith 2E0OKG in QSO from near Weston-Super-Mare with former Leominster amateur Phil MW0XTK in North Wales so it’s working really well. So the motto of this saga is to expect more than one fault….. The only downside is that the squeaker has returned in early April and is again on the music!
GB7VO / GB3VN / GB3JM Updates
In mid-May Josh, M0WYP/N9JDM visited the Hill Top House site to collect a spare HBRG Yaesu DR1-XE repeater. This was to extend the reach of the HBRG as he had plans for it for another digital repeater, GB3JM at Luston, Herefordshire. This was in preparation for the addition of a MMDVM unit with an associated “Top-Hat” Raspberry-pi unit to further extend the capabilities of the DR1 to accommodate multi-digital modes of operation including DMR, D Star, NXDN as well as the original Yaesu Fusion. While he was on site Josh was “volunteered” to assist Dave G4OYX in the re-equipping of the GB3VM crate after the Spring fault-finding exercise as the crate was stripped of the actual DR2 to allow for adjustments and testing of the duplexer. Josh was also able to help Matt G8XYJ in trouble-shooting another HBRG Yaesu DR1 unit , now at Hope Bagot as GB3VN from there had been transferred to Hill Top House a week or so earlier. This too, involved the addition of a MMDVM unit with an associated “Top-Hat” Raspberry-pi unit to further extend the capabilities of the DR1 to accommodate multi-digital modes of operation including DMR, D Star, NXDN as well as the original Yaesu Fusion.