Batboard

I have successfully programmed my GM360, the European equivalent of the CDM1550.

However, I want to lower the squelch threshold for weak signal work. I have done this many times with other Moto radios.

I have the "Tuner" Programmer and have read the Help pages.

Usually lowering the SQ threshold on other Moto radios is very easy - just involves moving a slider at 7 test freqs from, say, a setting of 12 down to, say 4.

However, the Help pages say that with the CDM1550/GM360, you need to align the Front End filters BEFORE you can adjust the SQ threshold.

I'm a bit reluctant to "dive in" without checking. Surely its possible to just go straight to the SQ alignment pages rather than having to go via the Front End alignment?? I don't want to go near any Front End alignment just in case its all automatic and defaults to some start position and then I have no idea of the original settings. Older stuff is nice and simple - you can note down the original settings etc. Maybe you can do this with the CDM1550 - although aligning a VHF radio seemed very odd - just one test point then manually working out offsets from default values and then inputting these values manually - all seems a bit primitive !!!

Thanks

Supposing the Front End Settings are correct just set Squelch settings to desired levels

I'm concerned that just going into the Front End page might reset Front End to default values and then you have no idea of original values - maybe I'm being too cautious!!! The Help pages are not helpful!!

I'd like confirmation that original Front End values are displayed and can be noted down just in case !!

Or that you can actually just go straight to the SQ adjust page.

Thanks

I just went ahead and lowered the SQ threshold.

There is NO need at all to align the Front End before you adjust the SQ. You can go straight to the SQ setting - as with all my other Moto radios - the Tuner Help Pages are misleading saying you can only tweak the SQ after you have aligned the Front End!!!

One thing to note is that you need to go to "File - read radio" when you use the Tuner - its a separate program rather than the usual integrated "Service" section of the RSS/CPS.

You also need to make sure the RIB battery is good - I think the Tuner has a higher current load requirement on the RIB compared to using just the RSS/CPS - or maybe my battery was going flat anyway!!!!

One thing I also noticed was that my GM360 was almost 1KHz off freq (970Hz). This definately had an effect on real weak signals. Quite a few of my other Moto radios were originally more off freq than I would have expected!!! Maybe they drift over time - but would a 3 year old radio drift 1KHz???

So how low did you set it

And... Since I have a CDM1250, I think my squelch is a bit tight as well.... Can you advise detail steps on how to lower it?

You need to use the Tuner software which is completely separate from the CPS Programming software. But the basic concept is the same as using Service Mode in older RSS BUT you need to remember to intially "Read" the radio when you use the Tuner software.

My original values were 46 for each of the 7 test freqs on 403.025 to 469.975 Mhz. I backed off the SQ slider on each Test freq until I could hear white noise - then I just increased the level until the SQ just closed. Because there is a small amount of hyteresis (ie. SQ closes at a lower level than opens) its a good idea to TX a test signal using another radio or sig gen on each of the Test freqs when you are making the adjustments to make sure that the SQ closes after you stop TXing. If the SQ stays open, just increase the slider by an extra one.

I ended up with a setting of 36 on each Test freq - this works great - nows opens on really weak signals - great for DXing. If you find the SQ opens on too weak signals , just increase each SQ setting by an extra 1 unit.

Remember to check that the radio is on freq (+/- 400Hz) - I found that my set was almost 1kHz off freq - weak signals were much improved when I tweaked the radio onto freq. Apparently it's very common for sets to drift by 1-2Khz during the 1st 3 years following manufacture as the crystal ages - after three years , drift is much less!!