OH3TR in Finnish
OH3TR in English
What is this hobby?
OH3RTR Repeaters in Hervanta, Tampere, Finland
Currently OH3TR operates two FM speech repeaters and an amateur television repeater under the callsign OH3RTR. Our 70 cm speech repeater, ATV repeater and 6 m speech repeater receiver are co-located with the OH3SHF microwave beacons at the Hervanta water tower where we also have our VHF/UHF/microwave contest station.
This picture is taken from the water tower observation platform to the northwest where you can see downtown Tampere with the landmark Näsinneula observation tower, with its OH3RNE repeaters. It should give you an idea of our site. You can find more pictures and a video clip on the page of our VHF/UHF/SHF contest station.
The 6 m repeater transmitter is located at our clubhouse, also in Hervanta.
On the right you can see our equipment racks at the water tower site.
In the rack on the right, top to bottom: 70 cm FM repeater, 70 cm DMR repeater, the GPS-based time and frequency reference for the beacons, 5.7/10 GHz beacon exciter, 70 cm RX multicoupler, 70 cm FM repeater computer interface, 6m repeater RX and 70 cm link TX to the transmitter site, 6 m and ATV power supplies, ATV PA, ATV up- and down converter, and the two units at the bottom are the ATV IF stages.The rack on the left holds the 24 GHz beacon exiter, some computer and APRS equipment and the 70 cm TX multicoupler with the duplexer on top of it.
OH3RTR 6 m speech repeater
QRT for the moment, TX antenna gone bad, RL ~ 5 dB :( (9.2016 onwards)
OH3RTR 70 cm speech repeater QRT, waiting for service
The repeater is again linked with the RATS R.NET linked repeater network
OH3RNE 70 cm DMR repeater
We also house the OH3RNE DMR repeater (434.525 MHz out / 432.525 MHz in).
The 70 cm repeaters share antennas through a multicoupler system so the coverage is pretty much the same.
OH3RTR 23 cm FM ATV repeater R.I.P
More info about the ATV repeater in memoriam and Team OH3TR ATV operations.
Future developments (in the year 2000 or so)
Many future developments have been discussed. A gateway between the 6 m and 70 cm repeaters has been about to be built for a long time, as the essential parts are already there. The Kyodo base stations have a balanced remote audio line and there are also unused control pins in the RYYDLAB controller, so the hardest work is going to be in keeping our overworked software guru awake long enough to get the necessary modifications made.
There have also been plans to increase the portable coverage of the 70 cm repeater even more by a diversity reception system. The system would basically consist of several receivers with directional antennas to the most important directions (e.g. downtown, main highways and the university/campus area) and a signal/noise voter that will choose the best available signal. With 11 dBd panel antennas we could improve the received signal from the main directions with 6 dB compared to the omnidirectional antenna we have now. Some of our members have showed interest in improving the LDG 68HC11 based 8-channel voter published in an April 1996 QST article and writing their own firmware to it, and we already have some surplus 450 MHz NMT base station receivers and antennas so who knows what will happen...
We also once discussed about linking the speech repeaters with the bygone OH3RNE 23 cm speech repeater (output at 1297.000 MHz) using a 86 MHz NBFM receiver connected in the ATV repeater RX IF line and a 70 cm receiver at the OH3RNE site tuned to the OH3RTR 70 cm output. Another way to go would have been to build a 23 cm speech repeater of our own with a Nokia TMN-1 NMT900 phone, but now the band is gone forever here in Finland.
Team OH3TR is also involved in technical support to the other repeaters (fi) in Tampere area.
Please have a look at our repeater links. Although the explanations are in Finnish, most pages we link to are in English.
Please point your link to .shtml-files instead of .html-files, when linking to OH3TR pages. Thank you!
Team OH3TR - Simply the Best
|© OH3TR 1996- (disclaimer)
Last updated: Monday, 07-Sep-2020 20:36:53 EEST
Send us mail.
Check this howto.