Batboard

Hi everyone,

Just have a question about the best setup on a portable for a particular situation:

In my area, fire companies are initially dispatched on a particular channel, and then each company responds on one of two "response channels" depending on whether they are a north company or south company. The above channels are repeated UHF in the 471-472 range. Once on scene, units are then switched to a "fireground channel", which are low power, simplex in the 453 range.
The problem is, dispatch cannot contact/monitor field units once switched to fireground, and vice versa; which means both the assigned fireground as well as the designated response channel for their area have to be monitored in order to not miss transmissions from dispatch, as well as your on-scene ops.
As we will probably be switching to this center in the near future, I was just wondering what everyone's thoughts were as for the best setup for our radios (Motorola HT1250's), short of the IC having to monitor 2 radios. Maybe some setting using Priority 1 and 2? I know talkback scan can cause some headaches... Thanks!

Depending on how good of an Antenna System that Dispatch 'hears' off of, I would say when a unit(s) arrive on location, just have them say : "Dispatch from Truck X we are on location switching to fireground xx", or something along the lines of that.

Then if they can, dispatch can talk/listen to traffic on the designated FireGround frequency, if range permits. That's the only idea I can think of as of now that could get that to work.

edit: Or, if command is on scene, just have him/her monitor the 2 radios, as I assume that dispatch would only have information that pertains to Command of the location anyways (or if not then command can then relay the info on the FG radio)

how large is your district? we use a main freq. a fire ground freq. and a tactical freq. our dispatch has the ability to operate on both main and fire ground simultainiously. so if dispatch cant raise the IC on main he can also us FG. do you have the resorces and ability to put a simple set up like a mobil (maxtrac/radius) on your FG freq. at dispatch? its kind of simple to do. put the radio in the dispatch room run a antenna to the roof/tower some good coax and your all set. now you can simulcast on both freq's just by using the PTT on both mic's.

as far as the HT radio a ht1250 450-520 split will work using the priority 1 + 2 put what freq is more important on 1. but you still wont be able to listen to both freq's at the same time. the way we operate is the IC is realy the only one that has to listen to two freq's.

Most of the fire departments around here that use a dedicated simplex fireground frequency have the IC toting two radios. The rest of them just use simplex talkaround on the primary repeater frequency/ies. None of them, that I'm aware of, have the ability to communicate reliably with dispatch on simplex.

The ideal (but somewhat cost-prohibitive, depending on your budget) solution would be to install a cross-band repeater in any of the apparatus that responds to every incident (a battalion chief's ride, for example) and have it repeat the fireground traffic back to dispatch on a dedicated frequency. Since this dedicated freq would only be used for base-mobile comms, you could use a frequency in pretty much any band, including lowband. Dallas FD has a similar setup where their UHF simplex frequency is repeated onto the city's public works trunk system, but it's use is somewhat sporadic.

around "here"... they have two channels... same frequency, but one is simplex, one repeated....

so you have a command channel that county hears

and a fireground, that command and everyone else hears, but not county, AND anything that county OR command says, is heard by everyone on fireground...

example...

channel 3 Fireground 123.45 Rx 123.45 Tx

channel 4 Command 123.45 RX 125.55 TX

same PL..

and no.. they're not operating on the air band, I'm using that as an example...

The problem with that is that units on TA can still cover the repeater output enough that the dispatch can't hear, plus dispatch can/will talk over the units on the TA ch.

I know 1st hand, and it took a long time to get the chiefs to actually use the fireground freqs. Of course it took awhile to explain when two people are 200 feet apart, it's better to use the TA instead of TRYING to get into a repeater 30 miles away.

. ""fireground channel", which are low power, simplex in the 453 range."

There is the answer, Fireground is low power and usally can not be used from a base station. This is due to not only the power limitation, but the antenna restrictions.

Let's assume the following:

471.0125/77.0 is Dispatch
471.0375/77.0 is North
471.0625/77.0 is South
453.0125/77.0 is Tac

In the rear of the Commander's rig, put two CDM mobiles and a R*I*C*K.

The Receive CDM is programmed as follows:

"TacNorth" Rx 453.0125/100.0; Tx 453.0125/77.0
"TacSouth" Rx 453.0125/100.0; Tx 453.0125/77.0

The Transmit CDM is programmed as follows:

"TacNorth" Rx 471.0375/77.0 Tx 474.0375/77.0
"TacSouth" Rx 471.0625/77.0 Tx 474.0625/77.0

R*I*C*K set for bi-directional. "Receive" CDM is set for low power on xmit.

When going off, commander selects the proper channel in both radios and activates R*I*C*K.

In Commander's portable, immediately after "Tac", program this channels:

"TacComm" Rx: 453.0125/77.0 Tx 453.0125/100.0

When on "Tac," Commander will talk directly to on scene forces, but will have Dispatch traffic over South repeated to him. He switches to TacComm and he can respond to Dispatch, but will still hear any local direct traffic from on scene forces. On scene forces still on "Tac" will hear Dispatch, but not Commander's reply to Dispatch. Commander has to keep changing channels, but this may be easier than having two portables.

Only downside is that Dispatch, which cannot hear on scene direct traffic, might override something; commander should hear the superhet noise and ask on scene unit to repeat.