firehouse issues, please help

[jmr3865]

Ok, I am fairly new to this stuff. I have 2 issues

1. We have a vhf gm300 w/ antenna @ the firehouse, I can be about 2 blocks away from the firehouse and I can barely hear the radio. What can we do?

2. We are looking to install a scanner in the firehouse that would scan 4 channels. I would need to run 5 or 6 speakers throughout the building with this. Each speaker would need it's own volume switch. What should I use for speakers and wires and ti attatch the speakers to the scanner?

thanks

[RKG]

As to #1, I haven't a clue without taking a look at the installation and maybe making a few measurements.


As to #2, you'll have to take the audio from the scanner out to a PA amplifier designed to handle the number and type of speakers you have in mind.

However, if you presently have a House Mike system (possibly tied into your Zetron Station Alerting System), you might consider wiring the scanner audio into the House Mike PA amplifier. In the typical installation, there is a preemption relay that disables the House Mike input when the House's Model 6 is in "PA On" mode (so that a House Mike can't trump an announcement by Fire Alarm). At a minimum you should be sure that the scanner audio is on the House Mike side of the preemption relay (for the same reason). An embellishment would be to install a separate (and additional) preemption relay on the scanner audio so that, when a House Mike was taken off hook, it, too, mutes the scanner audio, but that might be a bit of a wiring chore (since a sense lead would have to go back to each of the House Mikes).

If you go this route, consult with the guy who did your House Mike/Station Alerting system. Simply paralleling the scanner audio (at a nominal 8 ohm impedence) to the house mikes is likely to drag the line down so far that the mikes wouldn't work; most likely, your guy will recommend an additional PA input module so as to isolate (electrically) the scanner audio from the mikes themselves.

[emsbuff3240]

For the radio issue, check the connections from the feedline to the radio and to the antenna, also check along the feedline for any noticeable cracks etc...

For the scanner, what I would do is buy an amplifier and run the cable through the volume control into the speaker(all this can be got at your local radio shack ) but dont try to ask the people there what do do because most radio shack employees (at least around here) are incompetant at knowing about anything other than tv's cellphones and ipods.

if you have any questions about the scanner set up contact me via pm

[RadioSouth]

I'm getting the idea that the scanners speakers don't need to cover a wide area, just in a few different rooms ? If this is the case, at the price of scanners it might be a whole lot easier to pick up a scanner for each place you were going to put a speaker which would pick up the advantage of local control on the scan function.
GM300 wise somethings really wrong with either your firehouse setup or the radio you're receiving it on.

[KE7DZZ]

1. We have a vhf gm300 w/ antenna @ the firehouse, I can be about 2 blocks away from the firehouse and I can barely hear the radio. What can we do?


thanks

Buy or borrow a VHF swr/power meter, or contact a local ham and see if you can borrow a VHF antenna analyzer. My semi-educated guess is that your feedline and/or antenna has gone to poo.

[jmr3865]

Ok, I have to break down and by a swr meter. I will check the lines. As for the scanner. I want one scanner that will be locked up. too many hands on it is not a good thing. well, We have 4 bays that I would like to put a big one, or I could do 2. There is a wall dividing the bays. The other rooms are fairly small. I would even be willing to hook it up to the gm300. Thanks for the help. I will look into that at RS. I do want to change the volume per speaker @ the speaker.

[copcarguy]

As per your question about the pa, you have 2 choices if you want to do it right.

#1-Buy a pa amp with 70 volt speaker output. You run 2 wire, 18 ga to every location you want a speaker. You then buy 70 volt speakers with transformers. You also get wall mountable volume controlls for every place you want a volume controll. You run the 2 wire from the amp, into the volume controll then directly to the speakers. You have to do some math. Lets say you want 10 speakers at 15 watts each. Multiply 10X15=150. You want to buy an amp that can handle that wattage. You need a 150 watt amp.
You need speakers with transformers that will tap at 15 watts. Easy. (this is what most car dealerships have-little loss and a ton of speakers with some volume controlls). (http://www.bogen.com)

#2-Valcom has a system out of Virginia. Its a 24volt system that works very well. You run 4 wire 22 ga to all of your locations. You hook up a 24 volt power supply to the yellow and black wires to power the speakers. You then hook up your remainding green and red wires to your scanner. Each speaker comes with its own volume controll on the speakers. You can get them in both Horn style (shop or truck bays) and wall baffle style (office grade-pretty)
(most dr. offices and metal shops have this style). Easy to connect.
http://www.valcom.com

Hope this helps.

[jmr3865]

wonderful, ok, I woud also like to be able to hook up a stereo system to this thing so that music can play throughout the firehouse, a mic too if possible for pa.

[440roadrunner]

I have to break down and by a swr meter

An swr meter won't tell you if there's a transmitter power output problem. That's why most people on here insist on something like a Bird or Telewave power meter. Additionally, you really should have a dummy load that will handle the transmitter power at least for a few seconds.