Ritron RRX-450 Repeater on Amerateur Bands?

centuryvrproductions · #1 (**permalink**) 03-18-2013, 7:38 PM

Can a RRX-450 be tuned to 440? It programs in to the band fine and all but the status light blinks green.

Its obviously a 450-470 Repeater, But i would like to know if it can be done or how to move it to function on 440

ramal121 · #2 (**permalink**) 03-18-2013, 8:54 PM

If the green light is blinking, this means the VCO is out of lock. You can adjust the VCO to lock at lower freqs at the expense of loosing the higher freqs. A voltmeter is all it takes.

Also to consider is the duplexer as they are pretty wimpy. I don't how many threads are left on the tuning slugs after you go below 450MHz.

I have never tried to take a Liberty down to the ham bands, so I cannot speak on the performance nor the bottom limit. Experimentation is the only answer.

centuryvrproductions · #3 (**permalink**) 03-18-2013, 9:59 PM

Ok. I adjusted the VCO, and it adjusts fine at 460.000

But i tried programming to 450.000 and it wont lock. The test point stays at .19 to .20v and it wont move

At GMRS Frequencys it adjusts fine....

centuryvrproductions · #4 (**permalink**) 03-19-2013, 1:53 PM

It doesnt seem to do down past 450. It wont tune so it will lock

ramal121 · #5 (**permalink**) 03-19-2013, 10:51 PM

I had to dig out my service manual. Don't do many Ritrons, so I had to dig.

What you want to do is put the voltmeter on the indicated tie point and adjust to 4 volts on both the transmitter and the receiver. The transmitter needs to be keyed up to adjust and you tweek L207. On the receiver twist C180.

Links are to diagrams of locations...

https://dl.dropbox.com/u/2991846/TX.pdf
https://dl.dropbox.com/u/2991846/RX.pdf

centuryvrproductions · #6 (**permalink**) 03-20-2013, 12:24 PM

Yes, While it is on Frequency 460, It will transmit. and it will tune to 4 volts no problem.

It will not Key up at the frequency that I want to use, So How should I tune the VCO to my frequency (444)?

I have adjusted it to 4v just fine at the frequency 462, But i tried to tune it anywhere under 455, It just flashes and the voltage reads .10-.11v

centuryvrproductions · #7 (**permalink**) 03-20-2013, 3:36 PM

I Got it!

I Basically programmed in the frequency pair. (444)+5. Then Tuned the Reviever VCO. As well as the Transmitter.

With a bit of tweeking back and forth... it works well.

Thanks for the Help

centuryvrproductions · #8 (**permalink**) 03-22-2013, 10:29 AM

The repeater works but The Transmitter VCO will not stay locked. I got the pot tuned so it will transmit but it will not tune even up to a volt at the test point on the transmitter.

The pot screw is all the way out and will not go far enough...

Could i possibly add a larger or smaller value POT in there to be able to tune it to these frequencys?