Mixed mode Quantar growling

[Tim]

Hi Folks,

Have a VHF Quantar in mixed mode, and sometimes when it's keyed by an analog signal, a 'growling' sound keeps the repeater keyed up. No re-keying of an analog signal will quiet it, but if I keyup a digital signal, it will go quiet again.

I don't remember it doing this when only an analog system.

Just wondering if anybody else has seen/heard this, and what causes it.

Thanks,

Tim

[willbird287]

It sounds a lot like an issue that's been mentioned here before, always seems to be on VHF Quantars...

Does it sound like this?: http://www.youtube.com/watch?v=SRfvh0UTFHw

--Will

[Tim]

Yes, that's it.

I did a search for 'growl', but didn't get any
hits.

Tim

[willbird287]

There's some discussion in the following two threads (beware of serious OT derailment in one!) that might help you, altho it usually works out to be issues with the station itself. Good luck, keep us posted when you find the problem!

http://batboard.batlabs.com/viewtopic.php?t=44414

http://batboard.batlabs.com/viewtopic.php?f=10&t=47189

--Will

[escomm]

Probably very unrelated but have a very similar noise coming from a type 2 trunk system when it's hooked up to the 29dB preamplifier. Problems goes away when we bypass the preamp. Problem occurs with 2 identical preamps so I don't think it's the preamps. Even with the preamps fully attenuated down to "only" 19dB of gain the problem occurs. Stations are not configured for digital or mixed mode

[515]

I've heard this on UHF stations, too. I know the one I heard it on did have a wireline connection, and that they only use it in the analog mode. I haven't heard it in a long time on that channel, so maybe they resolved it.

I don't believe I've ever heard it on stand-alone stations where no wireline control is used, but that's not to say it couldn't happen... I'd be interested to know if anyone else has heard this on stand-alone stations.

My guess is that the problem is a bug in the Quantar, related to the wireline connection, as opposed to anything having to do with Astro digital.

[Tim]

The Quantar I'm running is a VHF stand alone system - doesn't even have
a wireline card in it.

There are no other communication systems for many miles (I live in
the boonies, and the quantar is at my residence until I get it up on the hill).

I've not had an opportunity to play with the different pl/dpl configurations,
but none of them are set for carrier squelch.

I've noticed that I do have a bit of desense on the system, so that may
be a contributing factor. However the growl occurs with strong signals,
not ones that are cycling because of desense.

Also, it does not happen all the time.

Tim

[escomm]

No wireline in my application where the problem is occurring but definitely occurs more the stronger the signal is. Turning the preamp back on leads to mobiles/bases in the field causing the grinding but portables not so much.....except when the portable is at the prime site and the preamp is turned on

[allplowedout]

Im excited to finally hear someone else experienced this "noise"...

I've heard it three times now after hearing the link to the uTube clip with the utube clip being the third time I have heard it.

a quantar I oversaw installation on experienced this exact noice a few times daily for about two weeks before having motorola directly get on board at which point the entire machine was swapped. the machine was a p25 enabled machine with 4 wire RTL ckt off site. Issue determined to be fixed once the machine was swapped as absolutely nothing else was changed and the replacement unit was programmed identical to the first one.

The only other time I have heard this noise was on 9/11 immediately after the first plane. it lasted for about two minutes then that repeater went off line.

the sound seems very similar to that of the tail end of dig mode but if you hear it side by side its not the same.

in closing I think its some sort of defect or the like in the quantar itself, or a product of some outside interference taking effect on a faulty component or such.

We never did get an answer from motorola on what went wrong with the first machine.

Good luck.

[Eaton90]

I've never heard a growl on our Quantars (UHF-L), but I often hear something like a two-tone Quick Call immediately followed by a "white noise" (The agency I'm monitoring never uses signalling). This sound can occur when someone is transmitting and it often interrupts this transmission but sometimes this signal can cancel itself. Sometimes it's possible to override this signal by keying the repeater especially with a mobile radio. I tried to make a sample audio record, but this signal starts for no reason at all, as for me and recording all the activity is a bit difficult in my situation.
My first guess was a repeater overloading signal, but sometimes it occurs when the repeater hasn't been busy at all.
What can it be?

[d119]

I've never heard a growl on our Quantars (UHF-L), but I often hear something like a two-tone Quick Call immediately followed by a "white noise" (The agency I'm monitoring never uses signalling). This sound can occur when someone is transmitting and it often interrupts this transmission but sometimes this signal can cancel itself. Sometimes it's possible to override this signal by keying the repeater especially with a mobile radio. I tried to make a sample audio record, but this signal starts for no reason at all, as for me and recording all the activity is a bit difficult in my situation.
My first guess was a repeater overloading signal, but sometimes it occurs when the repeater hasn't been busy at all.
What can it be?

Crapped up Government frequency coordination, if you're in the USA and on UHF-L. It probably is someones QC-II. Any chance you can set a VOX activated recorder on the channel and let it go until it happens, then isolate that segment of the recording?

[Tim]

Hi Folks,

I've seen some threads lately about problems with remote weather sensors mounted on towers. I believe they were all of the 'wired' variety, but I thought I might check mine. It is a wireless version, and upon inspection, I found some loose hardware. I removed the sensor, and the growling has not been heard for 2 days. It may be too early to tell, but the growling had gotten so bad that not even keying up a P25 signal would make it stop.

So, for now, all is quiet!

Thanks for all of the suggestions & encouragement.

Tim