New 224.800 Repeater On The Air - SEMARA
After an 8 month absence, the SEMARA Repeater Committee has restored 220 MHz service via our brand new BridgeCom Systems ComLink™ BCR-220 repeater! The new repeater went live at 9:05 PM on Thursday, July 16, 2015. Like our 2-meter and 900 MHz repeaters, this repeater resides at our 180-foot tower site and its antenna (temporarily a Comet CX-333 shared with our 2m APRS station) is also atop the tower. Full technical specifications can be found on our repeaters section.
This new unit replaces our old Hi-Pro repeater and uses our existing Bird Technologies/TX RX Systems duplexer that was purchased new by SEMARA in November 2010. Maggiore Electronic Labs which manufactured our old repeater went out of business in the Summer of 2012. Due to a frequency drift problem, it had been off the air since October 2014. At the July 2015 SEMARAbusiness meeting, a motion passed to purchase the new repeater and to sell the old one. There may be an interested local buyer, however if they decide to pass on it, we will place the old unit for auction on eBay.
The new 224.800 MHz repeater runs 30 watts output power as apposed to old one which was 20 watts. The temporary measure of the repeater’s outgoing CTCSS (PL tone) being different to stop desense (the transmitter feeding back into the receiver) is no longer necessary. There is a small amount of desense that still exists due to the sub-par antenna arrangement, however it appears to be mild in our initial tests. The new repeater is running 67.0 Hz for both transmit and receive. If you had set your radio up for a split tone, you will need to reprogram your radio for 67.0 Hz on both encode and decode. For the time being, the new repeater is running on its internal controller, which provides a basic CW ID and a short tail without a courtesy tone.
Future plans on the “to-do list” include interfacing the repeater to our brand new S-COM 7330controller. This is the same 3-port full-duplex controller we currently use on our 2-meter and 900 MHz repeaters. A completed PiRLP node (IRLP and EchoLink node 4215/W1AEC-L) and UHF Motorola GM300 link radio are ready to be interfaced to this new controller as well. When that happens, we plan to have this 220 MHz repeater full-time linked into the Quahog Repeater Network (QRN) via the link radio to the North Providence hub.
The repeater committee also recommends that the club approve the purchase of a dedicated 220 MHz repeater antenna to be added to the top of our tower. This would be the Sinclair Technologies model SD214 four bay offset dipole. The offset pattern should be east/west to add slightly more gain over the South Coast and less south to the ocean. We should request for it to be black anodized with a lightning spike. This commercial antenna will greatly improve the coverage and will resolve the desense issue that remains. The existing Comet tri-band antenna that is temporarily being used should also remain. It will continue to be used for our 2-meter APRS station and future UHF link radio, plus serve as a auxiliary antenna system for our 2-meter and 220 MHz repeaters should our primaries fail.
On Tuesdays, we plan to setup an automatic scheduler setpoint to separate the repeater from QRN and participate in “220 Tuesdays”. Via IRLP, it will link to the New England Reflector 912 Channel 4 (reflector 9124, the NEAR-220 channel) for the day, where it will be linked with other participating 220 repeaters including the MMRA‘s five 220 repeaters that link through their “HUB2”. 220 Tuesdays is a similar promotion as “900 Thursdays”, which you can also participate on via SEMARA’s 900 repeater. Both 220 Tuesdays and 900 Thursdays are New England-wide promotions to gain awareness and generate activity on the 220 MHz and 900 MHz bands respectively.
Richard J. Cabral, W1RJC
SEMARA Repeater Committee