I have a R1225 I am currently TX 154.xxx RX 159.xxx the repeater is in uni-directional mode what do I need to change to go both ways? (Don't be a smartass)
Thanks
Steve
R1225 Bi-directional ????
Moderator: Queue Moderator
Bi-direct duplexer.
Hello.
Bi direction duplexers are around, but not a standard off the shelf item, 6 cans in place of the normal 4.
A RICK can be set up to do bi and duplex, sometimes a bit easier.
Most VHF military radios do bi direction retransmit (repeater function).
So, the only thing that will slow you down is the duplexer, correct? wrong!
You can take 2 stock duplexers, use the 3 cans from each, set this up with a combiner and you are all set.
On VHF hi, you will have some big cans, but nothing like the 6 foot cans for lo band.
Bi direction duplexers are around, but not a standard off the shelf item, 6 cans in place of the normal 4.
A RICK can be set up to do bi and duplex, sometimes a bit easier.
Most VHF military radios do bi direction retransmit (repeater function).
So, the only thing that will slow you down is the duplexer, correct? wrong!
You can take 2 stock duplexers, use the 3 cans from each, set this up with a combiner and you are all set.
On VHF hi, you will have some big cans, but nothing like the 6 foot cans for lo band.
-
Dan562
- Posts: 533
- Joined: Mon Aug 23, 2004 7:30 pm
- What radios do you own?: Kenwood, Yaesu, ICOM, Motorola
Bi-directional Repeater
Hello Steve,
This is not a new idea ... /\/\ has been doing this for 28-30 years with SP requests. I'm not familiar with R1225 repeater but depending if the VHF repeater's receiver frontend bandpass filter is 4 MHz wide and you can software program both the F1 159 and F2 154 MHz on the RCVR and F1 154 and F2 159 MHz on the XMTR frequencies into the code plug. Then with TRC program F1 for 1950 Hz FT and F2 for 1850 FT.
You might need a couple of logic gates (sometimes known as Wild Card functions), at least one to provide a DC Low for the "switch around" PAIR of DPDT RF Coaxial Relays, using double shielded coaxial cable RG-400/U or RG-142/U and either BNC or N Type connectors.
You should also consider to generate a small amount of Delay to Inhibit the repeater's TX from Keying Up as the "switch around relays" pull in or release proventing RF being on the contacts. It also would be very hard on the RF Power Amplifier Stage. Oh yeah, don't forget to put diodes across the DC relay coils to prevent "spikes" being sent down the power leads. I've used a couple different types of duplexers for this application and never experienced any problems.
There will be some additional degradation in RF Power Output and Receiver Sensitivity due to the relays and additional coaxial cables.
Dan
This is not a new idea ... /\/\ has been doing this for 28-30 years with SP requests. I'm not familiar with R1225 repeater but depending if the VHF repeater's receiver frontend bandpass filter is 4 MHz wide and you can software program both the F1 159 and F2 154 MHz on the RCVR and F1 154 and F2 159 MHz on the XMTR frequencies into the code plug. Then with TRC program F1 for 1950 Hz FT and F2 for 1850 FT.
You might need a couple of logic gates (sometimes known as Wild Card functions), at least one to provide a DC Low for the "switch around" PAIR of DPDT RF Coaxial Relays, using double shielded coaxial cable RG-400/U or RG-142/U and either BNC or N Type connectors.
You should also consider to generate a small amount of Delay to Inhibit the repeater's TX from Keying Up as the "switch around relays" pull in or release proventing RF being on the contacts. It also would be very hard on the RF Power Amplifier Stage. Oh yeah, don't forget to put diodes across the DC relay coils to prevent "spikes" being sent down the power leads. I've used a couple different types of duplexers for this application and never experienced any problems.
There will be some additional degradation in RF Power Output and Receiver Sensitivity due to the relays and additional coaxial cables.
Dan