Paging Through a repeater

[JD]

I have a rerpeater set up, Motorola CDR700 VHF, with paging. We are using Minitor III,IV and V's. Twice know when paged , some of the pagers no not open while others do on the same page. We had a situation where one MInitor V opend and the other Minitor V did not. The county paging base is a older GE Master II. Could it be with the tones being off frequency ? Not enough pretime? does the CDM 1250 receiver need to be programmed a certain way ?
Thanks.

[RKG]

Most likely the problem lies with the repeater's attack time. If your encoder begins sending the first tone before the repeater has completed its keyup and pass audio sequence, the timing will be off. What you want to do is to increase the pre-time or page send holdoff time.

[Jim202]

Not only follow RKG's advice, I would try looking at the
repeater and the audio adjustments it has. What I mean
by this is that in order for the tones to be decoded by
the pagers, they must be in thier original form. If the
tones get distorted, most pagers will not decode them.

What I find to be a common problem is the way the
through-put audio in the repeater is adjusted. If you
can find an old manual for either a GE or Motorola
repeater that goes back some 15 or 20 years, they
always instructed you not to have the paging audio
tones go into compression. If this happened the tones
would be distorted and the pagers would not decode.

Now that I have said distorted audio a couple of times,
the way you prevent it is to adjust the audio tone level
input to the repeater. This is done by generating a
3 Khz deviated tone at 1000 Hz into the repeater
receiver. Adjust the repeater audio level to give 3 KHz
deviation out on the transmitter. No more than 3.5 Khz
deviation. This keeps the repeater from causing
all audio to go into compression all the time.

Then go back to the paging encoder and make sure
that the tone level out of it going to the transmitter gives
no more than 3.0 KHz deviation. If you follow these
steps, you will always decode your pages.

If you are using DTMF tones through the repeater,
you need to follow the same adjustment. The DTMF
tones have another quality to them that not many
people understand. It is called the tone twist. What
this is referring to is the difference in levels of the two
tones used for each digit. If the tone levels are not
close to being the same, you have too much tone
level twist and will have troubles on the decoding
end. Remember, the DTMF tone levels are just like
the paging tones. They don't want to be put into
compression.

Jim

[RKG]

Good suggestion; I should have included it.

[RF_Burns]

what kind of encoder are you using ? If its a MC2000 remote with signalling it was not designed properly for flat audio paging.

The paging tone deviation should be 3khz, but if its an MC2000 the deviation could be as low as 0.5khz for a 300hz yet in heavy compression (almost square waves) for a 1100hz tone. This could cause some pagers to work and others not to. Or some paging codes to work well and others to work lousy.

Since Motorola does not care to correct this, we had to design and install a circuit ourselves to fix the problem.

[JD]

Thanks for all the info. It is a Zetron Console with a GE MAster II, 20 years old, base. I will recheck the deviations again. It is really strange, this has only happened twice in 6 months. I think it has to do with the pretime, it is kind of a hybrid system setup. We have the repeater configured so that the first page will place the repeaters ptt line in service, then the second page will process through the repeater. We are doing this because the paging system will not do multiple PL tones , which is what each department needs. The dispatch center used the same frequency for communication and paging.

[RKG]

There is a trick that is sometimes used to solve attack time issues with stacked pages, and that is to put, as the first page in the stack, an unassigned capcode. The time spent sending this first page ensures that all relevant receivers are wakened and listening, and any timing glitches with the first page drop out of the equation because it isn't addessed to any unit.

However, as your stack grows longer, your mobile and portable receivers have to have their reset timer lengthened, or they will re-mute before the stack has been completely sent.

[firetech792]

JD....you didn't mention if this was like an in-building system or a wide area system, like for a town or county.
If its wide area, maybe its just an RF issue. Maybe they were in a fringe area when they missed the page.

[JD]

Yes, the base is 15 miles away, I think there is an issue with their tones.

There are Minitor IV's and V's that are paged directly from the base , they are within 10 miles almost line of site, and they miss pages.

[KH]

See if you can disable per-emphasis during the 4 sec the tones are going out. I asked rec3ently about a preemphasis disable on a Moto mobile and it turned out it had it, programmable input.

[RADIOMAN2002]

Are you stripping off the PL tones. They can cause problems when mixed with some paging tones.