XPR4550 / XPR5550 - Analog Mode Squelch Adjustment?

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g8tzl2004
Posts: 1128
Joined: Wed Sep 08, 2004 10:13 am

XPR4550 / XPR5550 - Analog Mode Squelch Adjustment?

Post by g8tzl2004 »

How do you adjust the analog squelch level in an XPR4550 or XPR5550?

The user can toggle between Normal and Tight SQ levels but I can find no SQ softpot adjustment in the Tuner software.

Hopefully its not a fixed factory "Normal" level which will probably be set too high for weak signal working?

On my MCS and CDM radios you can adjust the SQ softpots in the tuner software so that the SQ opens on a really weak signal. On XTL radios, there is a User Adjustable 0 - 15 SQ setting and level 1 is set just right to RX more or less unreadable signals...so you really need to set the XTL SQ level at say 2 or 3 but at least you have the option to set the SQ at the absolute noise threshold!!

There is an RSSI dBm adjustment with the XPR radios but I'm thinking that is only used to restrict TX based on the strength of the RX signal??

Hope someone can help.
g8tzl2004
Posts: 1128
Joined: Wed Sep 08, 2004 10:13 am

Re: XPR4550 / XPR5550 - Analog Mode Squelch Adjustment?

Post by g8tzl2004 »

Any ideas?
g8tzl2004
Posts: 1128
Joined: Wed Sep 08, 2004 10:13 am

Re: XPR4550 / XPR5550 - Analog Mode Squelch Adjustment?

Post by g8tzl2004 »

Any thoughts?
com501
Posts: 1088
Joined: Fri Nov 02, 2001 4:00 pm
What radios do you own?: Over 50 - All Motorola

Re: XPR4550 / XPR5550 - Analog Mode Squelch Adjustment?

Post by com501 »

There is no squelch pot adjustment. The DSP sets the squelch level according to the algorithm flashed into the firmware, either normal or tight. Mine opens on carrier squelch on UHF at around -123dbm. VHF both of my mobiles open around -124to -125dbm. I optimized my radios using autotune on the Aeroflex, but I could not tell any appreciable difference.
g8tzl2004
Posts: 1128
Joined: Wed Sep 08, 2004 10:13 am

Re: XPR4550 / XPR5550 - Analog Mode Squelch Adjustment?

Post by g8tzl2004 »

Thanks com501.

I wonder if you have checked how RX sensitivity compares for 12dB SINAD between the XPR4550 and XPR5550 for both UHF and VHF?

Is an XPR5550 more sensitive than a XPR4550? The portable XPR7550 is regarded as being significantly more sensitive than the earlier XPR6550...and official specs, as usual, are not a true guide to actual sensitivity..only a worst case scenario.
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