Please explain FCC assigned freq not same as our Hyteras programming

[daugherh]

With what you are wanting, and since the license is about to expire, you may be better suited looking at a system change.

You might want to look at something like the Motorola DTR700 radios. They don't require a license and each group could have a private talk group along with an all call feature. They don't have the second group ptt and I think only the sancom offer that.

Unless you switched to a digital DMR system with multiple repeaters in a trunking type system you won't get want you want easily.

 

[RollRed]

The guy who designed the system left the organization a few years ago. I have inherited this system and intend to improve it and get it in compliance.

Thanks again for everyone's help so far.

 

[RollRed]

Frequency Range(MHz) UHF: 450-470

like daugherh posted, it is a bit out of its range.
how did you get the 414 freq ?

I don't know.

That's what the Hytera software told me when I scanned my radio. There are 16 different frequencies/channels programmed, from 414.00625 to 456.00625.

 

[RollRed]

Frequency Range(MHz) UHF: 450-470

like daugherh posted, it is a bit out of its range.
how did you get the 414 freq ?

Here's what I see from the Hytera programming software.

 

[nokones]

Forgive me for being a noob.

I was asked by the school I work for to look into our handheld radio system. The person who set up the system left a while ago. I know a little about radio systems, but there's way more I don't know.

Our FCC license is up for renewal in the spring. That had me looking at our assigned frequencies, one of which is 461.275. I plugged a programming cord into one of our Hytera radios, as I was curious if we were even operating on our assigned frequency.

Here's where I need help.

Our handheld Hyteras are programmed to a different set of freqs for RX/TX. For example - channel 1 is 414.00625.

1. How do our assigned FCC frequencies translate into frequencies programmed on the radio?
2. How do we have four FCC assigned frequencies, but our Hyteras are programmed to 16 different RX/TX channels?

Thanks

I bet the radio operating range is something near 400-470 MHz and that is the CPS default channel freq., and probably a Federal NTIA allocated frequency for the Federal Government

 

[wtp]

well i see on that one the range of 400 to 470. that would now fit better.

 

[daugherh]

Makes sense now seeing that. Must be a slightly different model that does that range. You definitely want to reprogram with your frequencies and not use those as they are.

I'm not at my computer right now but tomorrow morning I'll send a more detailed message of how you could somewhat get what your after but with your license as it you're very limited.

 

[RollRed]

Makes sense now seeing that. Must be a slightly different model that does that range. You definitely want to reprogram with your frequencies and not use those as they are.

I'm not at my computer right now but tomorrow morning I'll send a more detailed message of how you could somewhat get what your after but with your license as it you're very limited.

Thanks Russ.

Our FCC license renews in the spring, so maybe we'll should look into adding a few more frequencies. Also, I don;t think we need the repeater channel, but I need to do some cross-campus testing with radios (on our correct simplex ch) to see if there's any loss in signal.

Another school I work with has 5 channels. Here's the other school's freqs.

Thanks again to everyone, I learned a lot today.

 

[dickie757]

Where is the license link? Was it scrubbed?

Really, do you and your community a favor and hand it off to a shop. How many radios do you think need programmed?

Something doesnt smell right here, besides the fact of 414 MHz. I know the suit to station spacewalks use comms in that spectrum.....but how could this have happened for years without notice? If said dood programmed them 1 year before he left, how many years ago is that?

I suspect OP did not read the radio correctly. Or read an unprogrammed backup.

 

[K4EET]

Hi @RollRed,

Wow! Did you inherit a real mess. Just so you know, the band segment of 420 MHz to 450 MHz is the 70 centimeter band for Amateur Radio operators. It is a small wonder that your radio system has not already been called out. Ten of the frequencies are in the ham band. Your CTCSS tones appear to be sequential IIRC so it is pretty obvious that your predecessor knew what they did was illegal. Typically those frequencies are not default frequencies from the factory since the full range of operational frequencies are not being used, especially the ones in the upper end of the UHF operational frequencies for those radios. Again, what a mess! You’re going to need a promotion and pay raise once you have the system back in the legal realm based on what you are going to learn about communications systems in the coming months. You’ll probably also need a 6 month vacation to rest your brain from being overwhelmed with information. At least you found the expertise that Radio Reference has to offer. You should consider hiring a consultant or radio shop to help you navigate the waters in unraveling the major mess that you were given. Best wishes to you and kudos too for wanting to straighten this mess out!

 

[emacs]

Those look to me like the default frequencies in the TC-508 radios.

We supplied a batch of TC-508s to a customer years ago, programmed per their license. Evidently, they required more radios, and someone at that organization purchased more online - then called us to complain that their new radios didn't work with the old ones!

Got them in, read them in CPS, and sure enough they had those lower-end UHF frequencies in them. The customer didn't realize the radios needed to be programmed, they just assumed they would interoperate out of the box.

Sounds like something similar happened in your case.

 

[mmckenna]

Here's what I see from the Hytera programming software.

Wow, that's a mess of federal, amateur radio and public safety frequencies. There's the real possibility of interfering with others there.

As others have said, those radios look like they were never programmed and someone just took them out of the box and started using them.

Reprogramming them so you are not in violation of your license, and not interfering with others, should be priority #1.

Step 2 should be to talk with your administration and figure out what they want to do, and specifically what their budget is. With what you have, you can reprogram those radios to be legal and use them simplex right now. That may be sufficient for what they need.
The mention of the repeater raises some concerns. If no one knew it was there, it's probably been years since it has had any sort of preventative maintenance done. If they are going to want to use that system, contact a local radio shop and get them to come out and look at it.


One thing I'd caution:
The school will look for the cheapest way possible. They'll likely let you do all the work. Unless you have some experience with this sort of stuff, it can all go sideways really quickly, especially if they are going to rely on radios for any level of school safety/response. Don't be the one guy that gets thrown under the bus when things go wrong, just because they want to save money.

Relying on a hobby radio site like this one for support of a radio system is not a good plan. You sound like you have some interest in this stuff, and that's good, but you need a professional to help get things fixed right now. Hobbyists are not the right people to be trying to help you design a radio system over an internet forum. Get the school/district to properly fund this so you don't catch the blame.

 

[daugherh]

@RollRed, listen to what @mmckenna has said above; especially if you want to use the repeater and the system you currently have.

Depending on the size of your campus I still would suggest looking at the Motorola DTR700. License free and can do multiple talkgroups legally. Find a local vendor that handles Motorola and reach out to see if you could get a handful of demo units to test on your campus. My workplace just did that and they let us have 3 units for about 2 weeks to fully test them out. The only reason I suggest these are because Motorola seems to be the only company with these ISM band, license-free, units. Because I had looked up your license yesterday before the link was removed - looking at your campus on Google maps appears that these units should do pretty well. I worked in a high school about the same size and that's what they used and they worked great.

Otherwise, as mentioned previously, please consult a professional 2way shop that specializes in this kinda thing. Don't risk your job, your freedoms, your financials, etc. on something that WILL come back to haunt you when/if something goes wrong.

 

[buddrousa]

@mmckenna
If the OP is Licensed for all 3 Frequencies could they not do this.
Channel 1 Repeater input SIMPLEX
Channel 2 Repeater output SIMPLEX
Channel 3 The SIMPLEX Channel SIMPLEX
and have 3 SIMPLEX Channels?

 

[mmckenna]

@mmckenna
If the OP is Licensed for all 3 Frequencies could they not do this.
Channel 1 Repeater input SIMPLEX
Channel 2 Repeater output SIMPLEX
Channel 3 The SIMPLEX Channel SIMPLEX
and have 3 SIMPLEX Channels?

If the FCC license shows all three frequencies as an MO station class, then yes, that could be done.

 

[speedway_navigator]

Forgive me for being a noob.

You are forgiven, we all started out that way.

Figure out how much traffic is or will be used to determine the number of channels versus talk groups/users on one channel.
Can you cover the entire school property without a repeater? A repeater is a range extender and does not affect how many people are using the channel or channels.
I know other shops have seen Hyteras on factory defaults.

2 sets of users can talk on 1 channel with DMR if you moved to that type of radio. DMR has an all call feature, you have to use a separate channel and scan it in analog mode to meet your need for that. It's not as fast as a DMR all call but does work except if someone is transmitting on the channel when you do your all call, that user will not scan to the all call channel.

 

[cavmedic]

Did you read a couple more radios to make sure the are all programmed the same? You could have a one off that’s not correct.

You didn’t specify if the radio you have read works with each of the other radios. How many other radios work with each other.

You have to get a baseline first to know exactly where you stand and then work from there.

 

[N4DES]

If the FCC license shows all three frequencies as an MO station class, then yes, that could be done.

It doesn't have to be stated it on the license as an MO. A lot of people do it, but it's not a requirement.

(2) For conventional systems the assignment of frequencies will be made in accordance with applicable loading criteria. Accordingly, depending upon the number of mobile units to be served, an applicant may either be required to share a channel, or, if an applicant shows a sufficient number of mobile units to warrant the assignment of one or more channels for its exclusive use, it may be licensed to use such channel or channels on an unshared basis in the area of operation specified in its application.


(i) Channels will be chosen and assigned in accordance with §§ 90.615, 90.617, or 90.619.

(ii) A mobile station is authorized to transmit on any frequency assigned to its associated base station.

Federal Register :: Request Access

www.ecfr.gov

 

[lenk911]

It doesn't have to be stated it on the license as an MO.

I don't believe you are correct. If you have a repeater (FB2 etc) and want mobile talk around on that repeater channel you must also show the repeater's frequency as a MO on the license. The frequency coordinator generally will not charge you.

(ii) A mobile station is authorized to transmit on any frequency assigned to its associated base station.

What the quoted rule means is you can use any base frequency for mobile use but you must have the authorization on the license. The exception to this is frequencies dedicated to paging where no mobile authorization is allowed.

(i) Channels will be chosen and assigned in accordance with §§ 90.615, 90.617, or 90.619.

You are quoting from Part 90 Subpart S which is 800 MHZ. Not applicable to below 470 MHZ..

Licensee's which are authorized VHF/UHF trunking stations (FB8 & MO8) are given exclusivity. Exclusivity (aka "clear channel") is no encroachment of the station's service contour (C) by a co-channel station's interference contour (I) and vice versa. Non trunking Public safety below 470 MHZ is afforded some protection of their contour by the frequency coordinator unless they surrender this privilege by letter. All other services below 470 MHZ it is generally stack and pack! Meaning in an urbanized area you will have neighbors within your service contour.

 

[RollRed]

Did you read a couple more radios to make sure the are all programmed the same? You could have a one off that’s not correct.

You didn’t specify if the radio you have read works with each of the other radios. How many other radios work with each other.

You have to get a baseline first to know exactly where you stand and then work from there.

To all who have posted. I learned a lot in the past week or so, but still much to learn.

Our radios are programmed correctly. We use three channels that mimic this:

• a repeater on the 461.275/466.275 pair
• simplex freq at 464.025
• simplex (talk around) on 461.275.

I can't explain how the Hytera programming gave me back those 1-16 frequencies. Obvioulsy, it was noob user error to start with.

My apologies to the list.