VHF Quantar Mixed Mode Operation Help Please?

[seleong]

I have set up a low power VHF Quantar for operation on the amateur band. I've run into a very curious operational problem that I am hoping someone might be able to help with:

From certain locations, I can operate the repeater with a 5W handheld operating in P25 mode.

At the same location, I cannot get the repeater to function in analog mode with anything from a 5W handheld to a 50W mobile.

Closer in, the repeater operates in either P25 or analog mode just fine...

Could I have my "Analog Receiver Function" or "Analog Repeater Function" options set incorrectly or not optimally? They are both currently set for the "C=PL/DPL" settings.

(we're running a very clean VHF 6-cavity Bp/Br duplexer with -112dB notches, and very tight roll-off skirts, with 1.1dB insertion loss - antenna is a StationMaster at 60 feet using 7/8" Heliax)

Thanks very much for any suggestions or recommendations!

Steve

[nmfire10]

I've never programmed a quantar so I'm taking a stab in the dark here. For analog, do you by chance have the squelch set for AND/OR Unmuting?

[N4DES]

You might have the squelch clamped down real tight in the analog mode. Take a look under the service tabs and check the squelch settings. I found that about 1/3 from the lowest setting is very close to the digital threshold and the factory setting is much higher.

Another thing to look for is receiver de-sense. Are you at a highly populated site? If so the receiver may be slammed with noise that the digital typicially ignores.

Mark

[Hartley]

Ditto on the suggestion to check the squelch setting - the factory snugs 'em up real tight, and it won't go unless the squelch is open.

On minor thing, I assume you are using wideband (5 kHz deviation) for the analog input - in theory, the noise floor will be slightly higher in wideband than in narrow P25 (but I'm not sure when (or if) it changes filters!

73 DE Hartley

[seleong]

Thanks to all who offered their suggestions!

We opened up the squelch from its 75%+ factory setting (per your suggestions - thanks again!), and the analog operation of the Quantar now nearly matches the operation in P25 mode.

Although it's an older Quantar, we sometimes experience a long/exagerated squelch tail (analog mode) and are curious if this is fixable with the firmware update per the Moto Field Service Bulletin (FSB10230).... Is this easy to do?

Thanks again for all your help!

Steve

[xmo]

If your station control firmware falls in the range identified in the FSB, then you should obtain the upgrade, however, you said yours is an older station. Because this issue only affects firmware from SC_020.14.021 to SC_020.14.035 which would be relatively recent vintage, it probably does not apply to you.

You may simply have the squelch set near the threshold or you may be experiencing varying levels of noise at the site.

You should first verify the station firmware version versus the FSB, then perform an extended site noise / effective receiver sensitivity test. After you have those results then you should follow the recommended Quantar squelch setting procedure.