Poor sound volume on EDACS w/396

[W2SJW]

Has anyone else noticed the quite varied differences in audio volume when you set any of the other system types to NFM instead of FM (usually happens when you leave modulation set to AUTO)?

I've got quite a few EDACS systems here in NJ, and the 396 ONLY lets you set the modulation to FM. This is causing systems like Camden City to sound downright awful at half-volume (very under-modulated, sounds like a whisper).

BTW - The analog AGC does nothing to help. Any ideas?

 

[FoeHammer]

Yes I think I am getting what you are talking about , for instance I am tracking a vhf system , mixed some groups analog some p25 and in my case I notice that no matter how i set the modulation or agc or att for that matter the ambulance units in particular seem to have low audio, the signal is good on the meter they just sound a million miles away , now the digital units on the other hand will knock you outta your chair , so I dont get it , i was thinking in my case the ambulance units might not have actually upgraded any radios , & may instead be patched into the system resulting in this , I dunno I can get decent audio on my local public safety trunked system , but its not spectacular and certainly nothing compared to the booming loud digital units on the vhf system , but those amb units on the vhf system seem to have very low audio even though the sig is good , Its mostly copyable , but sometimes you have to strain , I am using the latest firmware also, I hesitate to say its a prob with the scanner just because I have heard some units that seem to sound normal , but not too many
so I dunno whats going on ....

 

[W2SJW]

Yep, right on the money. It isn't just the 396, my 796 does it with any EDACS system as well (the upshot there is that's she's connected to a Moto commercial mobile speaker, which makes everything sound great!).

I always leave my digital AGC on, though. Most officers around NJ talk WAY too far from their mic's, and I can live with the loud dispatchers instead

 

[Voyager]

Has anyone else noticed the quite varied differences in audio volume when you set any of the other system types to NFM instead of FM (usually happens when you leave modulation set to AUTO)?

I've got quite a few EDACS systems here in NJ, and the 396 ONLY lets you set the modulation to FM. This is causing systems like Camden City to sound downright awful at half-volume (very under-modulated, sounds like a whisper).

BTW - The analog AGC does nothing to help. Any ideas?

Set all the frequencies to the correct modulation and they should all sound about the same level. Of course if you set some to NFM, you WILL be artificially raising the level and others with the correct setting will sound soft.

The real problem is that the AUTO defaults to NFM, while most systems on the air today are FM.

Joe M.

 

[FoeHammer]

Ok to make sure I am understanding , your saying the prob may be that when we programmed the system we did not actually set each freq in the system for the correct mode, I thought when you go into the system and set the system for fm it would take care of that , so I didnt think it would need to be set at the freq level , now im curious Im gonna go look if the freqs mod setup is independant of the mod setting for the system...

 

[FoeHammer]

No its not giving me the option to change modulation at the frequency level for a system , it only appears to be a system wide setting ,....

 

[W2SJW]

The 'auto' setting for a lot of the systems (except EDACS) will end up having the channels come out as NFM instead of FM. I don't mind this at all, because the analog audio come out of the scanner a bit louder at that setting. The only problem is that you have no ability to force an EDACS system to use any other form of modulation other than FM.

I've tried to on the 796 via ARC250 (where you 'can' change it on frequency line), but when it the changes get down to the scanner, it stays as FM...

 

[pro92b]

That's by design because NFM can degrade the control channel decoding at 9600 bps. To balance the audio better, change the conventional channels and Motorola systems to FM if they are louder than the EDACS system.

 

[Voyager]

No its not giving me the option to change modulation at the frequency level for a system , it only appears to be a system wide setting ,....

And is the system set for AUTO? (which in most cases defaults to NFM)

Joe M.

 

[FoeHammer]

No , even when the system is set to fm , I cannot change the modulation per frequency , only per whole system ....

 

[mikewazowski]

Foehammer, if you are referring to the Bell Mobility Radio Fleetnet system, your trunking system should be set to NFM.

And no, ambulance is not patched into the system. They have MCS2000 mobiles capable of operating on the system.

 

[Voyager]

Foehammer, if you are referring to the Bell Mobility Radio Fleetnet system, your trunking system should be set to NFM.

Are you sure about that? I thought it was a standard NBFM system, not SNFM.

Joe M.

 

[w8mkh]

I have the auto setting on here and helped the AEP edacs system

 

[mikewazowski]

Are you sure about that? I thought it was a standard NBFM system, not SNFM.

Joe M.

Channel bandwidth is set to 12.5khz in the rss.

Not sure whether that is NBFM or SNFM but NFM seems to work the best on the 396.

 

[loumaag]

Joe & Mike,

The original poster is talking about a EDACS system. The BCD396T does not allow you to pick a "modulation" mode on EDACS systems. If you build a EDACS Wide it is set to FM and if you build a EDACS Narrow it is set to NFM; you cannot alter that setting.

To W2SJW:
It might be that the problem is the rest of the radio is not programmed correctly. Leaving the setting in Auto is mostly always wrong on the BCD396T since the majority of all FM communications are in FM mode (Uniden definition) as opposed to the default NFM (again Uniden definition).

 

[mikewazowski]

Joe & Mike,

The original poster is talking about a EDACS system. The BCD396T does not allow you to pick a "modulation" mode on EDACS systems.

I think we both realize that Lou.

However, the second post in the thread references a Motorola system that FoeHammer is having problems with. Perhaps he should have started a new thread since we now seem to have two separate threads conbined into one.

 

[FoeHammer]

Ya it does looks like its a different thing I can change the modulation fine
Its just that some units seem to have pretty low volume no matter what mod is set at,, I dunno if its an actual problem with the radio , or just me hearing the difference between those that talk close to mic & those that dont , as well as the difference between the digital & non digital units anyway sorry W2SJW I thought it might be the same issue ,didnt mean to confuse your thread...

 

[Voyager]

Channel bandwidth is set to 12.5khz in the rss.

Not sure whether that is NBFM or SNFM but NFM seems to work the best on the 396.

Well, that would be closer to SNFM, then (AKA Uniden NFM), but it's a little wide for SNFM. Usually SNFM is limited to 11 kHz (10 kHz typical). NBFM is usually 16 kHz limit (15 kHz typical). 12.5 kHz is pretty much half way between the two.

I never really noticed the difference between the RSS selections and the FCC bandwidth limits, but SNFM is 12.5 kHz in the RSS/CPS. NBFM is 20/25 kHz in the RSS. Maybe they are referencing the receiver maximum bandwidth rather than the transmitter bandwidth. That would be about right.

Joe M.