VHF High Band Equipment Question

[dereckpristas]

Can you have a single repeater and have it where you can have say the PD and the EMS talk on seperate channels at the same time? Or is this an 800mHz only type thing. What kind of equipment is needed? Thanks!

Dereck

[nmfire10]

Well, you can get a repeater that scans but that really won't work very well. You can setup multiple PL's so they don't hear eachother. But no matter what, they can't both be having conversations at the same time. That would require a trunking system. It has nothing to do with 800mhz. You can have trunking on UHF or VHF if you so desire.

[dereckpristas]

I need to know what are some model #'s and brands of VHF Trucking repeater systems. Thanks!

Dereck

[w7com]

Most truckers use 27MHz and run simplex.

[Nand]

If it is only two channels you need, you likely should just use two repeaters.

Trunking only pays off when you have many different groups share several repeaters. It is done under computer control and is called trunking.

Perhaps you should make it known here what you really like to accomplish. There are lots of people here that can give you excellent recommendations for similar situations.

Nand.

[w7com]

Yeah, sorry about the CB joke.

I doubt that you would be able to get EMS and PD on the same license on VHF. IIRC they are in different services (PF and PD?)

More information on exactly what you are trying to do would be helpful.

[Nand]

No, it was a good joke.

Search for “trunking” in Google and you will never make that mistake again.

Nand.

[dereckpristas]

Well, here's what we're trying to do. The PD has a very OLD Type II system and we have a VHF Lo system. We are wanting to both get newer systems, but the same. We need to operate on the same system, yet seperate channels and be able to talk simultaneously (or however you spell that). So...that's what we're going for...anymore questions just email me. Thanks!

Dereck

[RKG]

1. You can put PD and EMS on the same VHF channel by treating each as "Local Government."

2. Trunking on VHF (or UHF for that matter) isn't practical where all the available channels already have co-channel users. As a practical matter, voice channels assigned to a trunked system have to be essentially "clear channels." That is why, outside of the military, trunked systems are on 800 (and soon to be, 700) mHz.

3. Nand is, as usual, correct: the rule of thumb for a trunking system to make sense is that you would license 5 frequencies (one control channel and four voice channels) and you would have not fewer than 10 working talkgroups. For only two talkgroups, you would need three channels (one control and two voice), and (apart from the fact that a three-channel trunked system would not be approved), you would be tying up three channels in order to work two agencies, which inverts the concept of spectrum conservation that trunking is all about.

[tom IL]

If I understand your statements correctly there is no reason you can’t use two repeaters, as long as they are both vhf high (if that’s the band you want to use).

[w7com]

What type of trunking system does the PD have? How many talk groups, channels, units? What is "old" about it? Is there a reason you wouldn't want to upgrade it and have fire join them?

[dereckpristas]

Their system is an old Type II that is approximately 7-10 years old... Now don't quote me on that because I'm not exactly sure on that. All I know is it looks old, gets repaired a lot, and needs to be upgraded/replaced. We wouldn't have just PD/EMS on the system. There would be a need for approximately 15 talkgroups and 2 simplex channels. Other than that, that's about all the info I've got. PM me with questions, or post.

Dereck

Thanks for everyone's help. Can someone tell me what my options are with a VHF trunking system (makes and models). I just want to do some research. Thanks!

[Tom in D.C.]

Dereck,

You should probably forget VHF trunking. While possible in theory, getting assigned six or eight or ten channels on VHF for your exclusive use in your town is nearly impossible. On UHF the trunking systems are usually cobbled together by using a PD's existing ten or twelve 460 or 453 mHz channels, like was done recently in DC. But up on 800 there's more spectrum, 45 mHz offsets, and the technology to control areas of coverage better
(assuming the seller and/or engineer of the system does the
necessary work!).

And, the FCC service IDs have all been upgraded. Nowadays you will find most of the stuff listed as PW for fire, EMS, etc. I can't remember if it includes PD but it may. Take a look at FCC or Perconcorp's site to find out.

[CuriousGeorge]

And, the FCC service IDs have all been upgraded. Nowadays you will find most of the stuff listed as PW for fire, EMS, etc. I can't remember if it includes PD but it may. Take a look at FCC or Perconcorp's site to find out.

Yes -- all public safety (conventional) is PW now. (Different service code for trunked systems but still shared by all public safety users.)

You still have to deal with the old PO, PF, PH, etc. coordinators for their respective frequencies but almost all the channels are officially available for any public safety agency to use and even the ones that aren't are available for use by others if the coordinators and FCC say so.

Don't want to count our chickens before they hatch but we've been working on a license since January and (knock on wood) will have it finish with the coordination process this month. And not for a lack of work on the coordinators part either. A single channel VHF repeater using one PH frequency and one PO frequency, for EMS (formerly "PM") purposes. Too many co-channel and adjacent channel users around here.

[nmfire10]

Dereck... Is this for something at home or on the campus? I'm a little lost on what the college PD and EMS would need 15 talkgroups for....