HT1250 MDC Decode annoying tone

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Tim
Posts: 448
Joined: Wed Mar 20, 2002 4:00 pm

HT1250 MDC Decode annoying tone

Post by Tim »

The FD finally started using MDC1200, so I turned on the necessary
stuff on the 1250.

Xmit works fine, RX also, but there is an annoying tone whenever
there is any traffic received on the channel.

Did I select something wrong?

Oh, I think I hear the same tone whenever I get a QCII
decode as well.

Thanks,

Tim
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FDC_100
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Joined: Tue May 18, 2004 7:17 am

Post by FDC_100 »

The HT1250 has an inherrant problem with the MDC decode ID on certain frequencies. I had the same problem, and after many hours of hair pulling cursing, I ended up just turning it off.

There were a few others on this discussion board that had it happen to them as well. Apparently it's a firmware problem.
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Josh
Posts: 1931
Joined: Mon Sep 03, 2001 4:00 pm
What radios do you own?: APX4K, XTL5K, NX5200, NX700HK

Post by Josh »

FDC_100 wrote:The HT1250 has an inherrant problem with the MDC decode ID on certain frequencies. I had the same problem, and after many hours of hair pulling cursing, I ended up just turning it off.

There were a few others on this discussion board that had it happen to them as well. Apparently it's a firmware problem.
This isn't a problem I've ever come across. What does it sound like? I have DOS enabled on my units, which cuts the MDC noise down but that's it.

-Josh
Tim
Posts: 448
Joined: Wed Mar 20, 2002 4:00 pm

MDC Decode tones

Post by Tim »

Hi Josh,

Doing some testing, it has to do with the transmitted PL.

If doing MDC decode on non PL channel, then no bogus tone is heard.
The bogus received tone varies in frequency with the PL input. With
the volume control at 12 o clock (about halfway up), the tone is
very noticeable.

Sounds like Mot forgot to put in some kind of PL filter in this mode.

- or - am I doing something wrong :roll:

Tim
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mr.syntrx
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Joined: Wed Apr 28, 2004 10:09 pm

Post by mr.syntrx »

Wasn't there an SRN for that?
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KC8UWK
Posts: 33
Joined: Tue Dec 09, 2003 4:33 am

Tone

Post by KC8UWK »

Could it be the IDer the MDC tones...???
73

Heath
KC8UWK

You might be a redneck firefighter if:
... two or more of your trucks have been pulled over for drag racing to a scene
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KC8UWK
Posts: 33
Joined: Tue Dec 09, 2003 4:33 am

Post by KC8UWK »

When you hear that tone does any numbers show up on you display screen on the radio... I have that and when I hear a weird tone it was the another unit transmitting there ID normaly at the beginning or at the end of each transmittion... Depending on the progam.
73

Heath
KC8UWK

You might be a redneck firefighter if:
... two or more of your trucks have been pulled over for drag racing to a scene
Tim
Posts: 448
Joined: Wed Mar 20, 2002 4:00 pm

tones

Post by Tim »

Hi Heath,

No, even if the transmitting signal does not do any
MDC encode, the funky tone is still there.

It's only there if the 1250 is configured for MDC signalling,
or if the channel has no PL.

Tim
louis
Posts: 89
Joined: Tue Dec 03, 2002 3:09 am

Post by louis »

You need to change the band pass filter in the tunning software and yes there was a srn.

Increase it.

I have also had probelms with certain pls, dpl and ltr data on a ls
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HumHead
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Post by HumHead »

Amateurs train until they can do it right. Professionals train until they cannot do it wrong.
Tim
Posts: 448
Joined: Wed Mar 20, 2002 4:00 pm

Hum

Post by Tim »

Hey, Humhead,

Thank you very much for the explanation.

Changed all 3 to 57hz, and it works great.

Thank you again!!


Tim
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