Batboard

We are using a 25W Quantar as our HAM repeater in Dual mode, also in scanning receiver mode allowing for the standard input and an alternate. CH1 receives and transmits on the same PL, CH2 receives with a DPL and transmits with a PL. Both CH1 and CH2 have Multi-Nac enabled. Most of the group uses commercial grade radios (Public Safety grade Motorola, Icom, etc.) We have noticed on our commercial radios that the radios are muting audio intermittently when users are using the channel specified for PL squelch on the repeater's receiver. This indicates that the Quantar's transmit PL level is dropping below the threshold required by the receiver radios at times or being distorted so badly the radios mute, though on the service monitor it shows PL level around 750hz dev. We are not noticing the PL dropping out on the amateur grade radios (probably because they require lower PL levels to unmute CTCSS)

When I come in through the second receiver running DPL, I notice the CTCSS does NOT cut out on the commercial radios receivers. I was under the assumption the Quantar's receiver strips PL/DPL and re-applies it to the final transmit audio so I don't see how this change from PL to DPL on the input is affecting it. The PL dev level in the Quantar RSS is set to the default 17%.

I also have the receiver IF set to 15-12.5K to allow better rejection of a near channel system. Although it is set this way....it does NOT appear the Quantar receiver is clipping over dev'ed audio, if you are listening on an amateur radio or in carrier squelch to the output you hear EVERYTHING, so audio doesn't seem to be cutting out of the repeater's receiver...it's just PL seems to be not hot enough on the transmitter at times to open the commercial radio's receivers.

Any ideas, insight or suggestions would be welcomed!

You need to match your subscriber units to the IF of the repeater. Keep in mind that the repeater is generating HALF the PL it normally does when in narrowband mode (2.5kHz). If you program one of your subscriber radios to 2.5kHz, does the problem go away?

Verify the Tx Rated Deviation in the Channel Information > Basic tab is set to 5.0kHz. You can then set your Receive Channel BW in the same tab to NARROW 12.5-15 but be advised that it WILL be noticeable on weaker signals. Additionally, you show me an off the shelf "ham radio" that's doing rated spec with regards to deviation and I'll show you beachfront property in Arizona. They are all overdriven and once you start listening to things, you'll notice it.

If you are still having issues, you need to go back through the Quantar with the book and perform the deviation alignment and modulation compensation procedures again.

Oh, and thanks again for fixing the fiasco on 448.220.

-You know who.

Thanks! So the Receiver settings (deviation level) determines the TX levels as well...good to know! I'll try that . I Did set one of my commercial radios to narrow and it didn't seem to make a difference but I'll try it with some others. Either way I thik we'll switch from 12.5 - 15Khz spacing setting to 20-25khz. IF on the receiver.

Appreciate the reply "you know who!"

No problem man. The best thing to do is make sure you've done a *full* alignment of the station, and that you've done it properly. To the lay person, the alignment can be a bit deceiving, especially in the deviation screen. It's important to have your service monitor properly set up, and to enter the observed deviation levels, not the desired deviation levels.

Reference modulation compensation primarily deals with things like low-speed data (trunking & DPL), but it's important to align it properly as well. Observe the square-wave pattern on the service monitor and adjust it for optimum "squareness".