Multiples frequencies for the same channel ?

[NATEMK7]

Can somebody tell why some business will use many frequencies for the same channel?
Can a Motorola XPR model can transmit on many frequencies and recieve on many frequencies at the same time?!
Even if they use many repeater for a building, as every departement have one, why so many frequncies? If you choose canal 1 or 4, it will spread on freakin' 5 or 6 different frequencies! But with the right talk group for each canal! WTF!?
Let say for only 4 channels, why not only use one or two frequency devided on the two time slots with four talk groups?
Does it exist a kind of repeater that switch/alterned between frequencies to be more secure?
Any idea guys?

 

[quebecradioguy]

Im not 100% sure I follow here, but I woukd say your talking about a Trunking system!

 

[mmckenna]

Can somebody tell why some business will use many frequencies for the same channel?

A link to a specific business or FCC license would be super helpful.

Can a Motorola XPR model can transmit on many frequencies and recieve on many frequencies at the same time?!

No. It transmits on one frequency at a time. It'll only receive one at a time, also.

Even if they use many repeater for a building, as every departement have one, why so many frequncies? If you choose canal 1 or 4, it will spread on freakin' 5 or 6 different frequencies! But with the right talk group for each canal! WTF!?

???

Might be a multicast system to get the coverage they need. Might be a trunked system. Kind of hard to decipher what you are talking about here. Remember, a picture is worth a thousand words, or in this case, a link.

Let say for only 4 channels, why not only use one or two frequency devided on the two time slots with four talk groups?
Does it exist a kind of repeater that switch/alterned between frequencies to be more secure?
Any idea guys?

Trunking?
Dual slot?
Again, specific link would really help us answer your questions.

 

[JackTheWebDev]

Are you using a SDR or something to determine that its transmitting on so many different frequencies by any chance?

 

[NATEMK7]

Yep! I have use a sdr to know what frequencies the radio transmit when I push the PTT!
But even with that, I am not able to reach the repeater to make contact!

 

[Asunakiyori]

*stares at what the Main site of Radio Reference is for*

 

[mmckenna]

Yep! I have use a sdr to know what frequencies the radio transmit when I push the PTT!
But even with that, I am not able to reach the repeater to make contact!

You need to be in range of the repeater. Sounds like you are not.

Also, an SDR is not a calibrated piece of test equipment and they usually have awful filtering. With a strong nearby signal, like from your radio, it's entirely possible that it is overloading the SDR and making the signal show up in multiple places on the RF spectrum.

 

[NATEMK7]

No worry! I'm at the range of the repeater 100% as I am on the building!

I try to use my ham radio with the Motorola systen where I work as we don't enough if that info can help!

Just more info to help you guys to help me!

I am able to recieve the channels 1 to 4 on mutiples frequencies with each of one a different group as follow...

Channel#1 456.7000 CC11 TG110 TS*
Channel#2 456.7000 CC11 TG120 TS*
Channel#3 456.7000 CC11 TG130 TS*
Channel#4 456.7000 CC11 TG140 TS*

TS* = seems to change automaticly!?!?

I can transmit 20% on the time on 456.7000 with CC and TG but 100%!
When I recieve a call I'm 50% able to reply if I push the PTT quickly as if they are a "window time"..

I try to add or minus 5.000khz for 461.7000 or 451.7000 and nothing happen on the 461.700, so it's inccorect but on the 451.7000 when I try to transmit all radio's DEL light turn on and flash in red!

Any idea?

 

[mmckenna]

No worry! I'm at the range of the repeater 100% as I am on the building!

I try to use my ham radio with the Motorola systen where I work as we don't enough if that info can help!

Understand FCC Type acceptance if you are in the USA. Amateur radio gear is not necessary legal to use on Part 90.

Just more info to help you guys to help me!

I am able to recieve the channels 1 to 4 on mutiples frequencies with each of one a different group as follow...

Channel#1 456.7000 CC11 TG110 TS*
Channel#2 456.7000 CC11 TG120 TS*
Channel#3 456.7000 CC11 TG130 TS*
Channel#4 456.7000 CC11 TG140 TS*

TS* = seems to change automaticly!?!?

So, when you says "channels", are you referring to the channel settings on the work radio, as in the knob on top?

From what you are showing, that would be a single channel trunk system, in very generalized terms.
Same frequency
Same color code
Talk Groups are sort of a virtual channel they can share multiple groups of users on the same system and they won't hear each other.
Time Slots will change depending on what's available for use or what has been programmed. The system looks for a free timeslot and uses that.

I can transmit 20% on the time on 456.7000 with CC and TG but 100%!
When I recieve a call I'm 50% able to reply if I push the PTT quickly as if they are a "window time"..

This is a major red flag to me.

Answer this question honestly, with no B.S.:
Do you have written permission from the owner of that radio system to access/transmit on it?
This will be a "yes" or "no" answer.

If you do not have written permission to use that system, STOP. You are actively violating many FCC rules.
Amateur radio operators, hobbyists, employees, or anyone else does not get a blanket free pass to access any radio system they feel like.

If you do have permission, have the system administrator either issue you a properly programmed radio, or ask their radio tech for help programming your radio to access their system, if and only if:
The radio has FCC Part 90 certification
The radio has not been modified
The person who's name is on the actual FCC license has said it is OK and given you written permission.

There are precisely ZERO variables here. You either have permission or you do not have permission. There is no waiver for hobbyists. FCC rules are real. Trying to hack into someone else's radio system can get you in trouble. Even if you have permission, it sounds to us like you do not have the experience or technical understanding to be programming your own radio to access this system. There are very specific FCC rules that address this sort of situation, and it really sounds like you are in violation of those.

I try to add or minus 5.000khz for 461.7000 or 451.7000 and nothing happen on the 461.700, so it's inccorect but on the 451.7000 when I try to transmit all radio's DEL light turn on and flash in red!

Any idea?

Yeah, you really need to stop what you are doing.

Get your amateur radio license and use your amateur radio on amateur radio frequencies where it belongs.

 

[wtp]

look up the term desense for a radio.
OK here it is anyway...

desense for a radio - Google Search

 

[NATEMK7]

Hey ohh! I was unaware that such regulation exist Mr. Mckenna. As we never stop to learn, thanks for bringing up the knowledge on this! I hope that I did any damage to anybody neither on equipment. As verbal approbation is not legit and to seek a written permisson seem to formal to me for that. I have no other choice to forget to play with this as it is against the law. Thanks to everyone who try to help me, sorry that I have lost your time with that and have a good one! Cheers!

 

[nokones]

With some exceptions, all Part 90 Type-Accepted radio transmitters, transmitting on Part 90 allocated frequencies, are subject to a Radio Station Authorization. This Radio Station Authorization only gives the licensee's owned radio transmitters that authority. Radio transmitters owned by non-licensee parties, such as employees, are not authorized to transmit on any Part 90 allocated frequency unless they possess a written Frequency Use Agreement, pursuant to FCC Rule Part 90.179, from the licensee.

 

[mmckenna]

Thanks to everyone who try to help me, sorry that I have lost your time with that and have a good one! Cheers!

Get your amateur radio license and keep learning. You just need to make sure you are doing this on the correct frequencies, and amateur radio is the right place.

Most of us are always happy to help those that want to learn. What we won't do is assist you in doing something illegal, against the rules, or would otherwise cause issues.

 

[NATEMK7]

Thanks Mr. Mckenna, it is greatly appreciated for the guidance! I will look forward to get my license to go deeper and increase my knowledge on the technical as the legal side. As I just learn, it is a privilege and not a right, and if we act unproperly and unsafely, we can loose that privilege. So act accordanly! The more I learn the more I am amaze by the radio world and is capability the more I look my cellphone as an unpowerful FisherPrice toys for the common people who don't want to learn how stuff works! But hey, thanks to get me aware of it! Have a great one!