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Problem with Windham NH Fire

kevind963

Newbie
Joined
Jun 22, 2012
Messages
4
Hey guys, I'm new to all of this so please bear with me on this issue.

Windham NH has two fire frequencies. The first one (154.17500) is for dispatch and the second (452.92500) is for operations. 95% of the time everything works well but 5% of the time the scanner (BCD436HP) stays on the wrong frequency and I just hear is a very low hum.

Example:
154.17500 - Dispatch Tone Out
452.92500 - Units responding
154.17500 - Dispatch immediately begins providing additional information about the call after the units are on responding. I think the scanner is staying on the operations frequency and not switching over back to the dispatch channel.

When this happens there is just a low hum. It's not the same as a transmission that can't be understood. Is there anyway to adjust the sensitivity so it switches over the correct frequency?

Thanks
 

ecps92

Member
Joined
Jul 8, 2002
Messages
10,535
Location
Taxachusetts
Windham Fire is VHF Only

the UHF is a downlink - Apparatus/Firefighters do not have a UHF Radio
452.9250 is a downlink from the remote RX site, monitoring 154.1750

For someone with a Scanner, since Windham 154.1750 is simplex,, if you can hear 452.9250 listen there as you will hear even a portable on the fire side of town, where 154.1750 would barely break squelch

IS the hum on the VHF or UHF?
IF UHF, it could be the Tone Remote tone...


Hey guys, I'm new to all of this so please bear with me on this issue.

Windham NH has two fire frequencies. The first one (154.17500) is for dispatch and the second (452.92500) is for operations. 95% of the time everything works well but 5% of the time the scanner (BCD436HP) stays on the wrong frequency and I just hear is a very low hum.

Example:
154.17500 - Dispatch Tone Out
452.92500 - Units responding
154.17500 - Dispatch immediately begins providing additional information about the call after the units are on responding. I think the scanner is staying on the operations frequency and not switching over back to the dispatch channel.

When this happens there is just a low hum. It's not the same as a transmission that can't be understood. Is there anyway to adjust the sensitivity so it switches over the correct frequency?

Thanks
 

kevind963

Newbie
Joined
Jun 22, 2012
Messages
4
Thanks for your help! Sorry for not getting back to this sooner but I wanted to play around with some settings and make sure I knew exactly what was happening.

What I found is that 452.9250 does not contain any of the audio from dispatch including tones. Only 154.17500 includes audio from the dispatcher. 452.9250 only has audio from firefighter portables and vehicles.

I have attached a file of the "static" I was trying to describe. The recording is immediately following a dispatch tone on 154.17500. Instead of going back to 154.17500 to listen to the dispatcher the scanner went to 452.9250 and the dispatch audio was missed.

Like I said, I'm really new at this so I can't answer the VHF/UHF question. But does the recording sound like the "Tone Remote tone" (I don't know what that is either)?

Any help or advice would be very much appreciated! Thank you!
 

Attachments

zerg901

Member
Premium Subscriber
Joined
Apr 19, 2005
Messages
2,675
Location
Arlington MA
kevind963 you are trying to understand a fairly complex radio system. Lets see if I can help.

In the beginning Windham FD probably had a ?40? foot antenna at their fire station. All comms were on 154.175 Mhz. The dispatcher would transmit and receive off that antenna. Then at some point they found there were some areas in town where the dispatcher could not hear the portables. So the solution was to put a 154.175 receiver on a high spot somewhere - and ship the messages from the portables back to the dispatcher via a UHF (4XX Mhz) freq. At the dispatch office - they installed a 'voter'. The 'voter' compares the signal coming in via the UHF link versus the signal coming down the wire from the 30 foot antenna at the fire station. The voter picks the better signal, and presents that to the dispatchers console.

With me so far?

---------------------------------

bonus points - homework

https://wireless2.fcc.gov/UlsApp/UlsSearch/licenseFreqSum.jsp?licKey=1193677 - this is part of the WPKV459 radio license for Windham Fire

you can click on the Loc# to see which locations corresponds to which transmit freqs

FB2 = repeater (dont ponder this too much now)
FBS = secondary base station
MO = mobile or portable radio
FX0 = link station - (point to point - one fixed location to one other fixed location) (maybe auto or manual - not sure exactly - maybe activated by chipmunks)
FX2 = automatic link station
FX1 = manual link station - ie - a link station activated by a human being

Looks like Windham has (or is planning to operate) a repeater on 154.175 with an input freq of 159.3675. Also looks like they are planning to have 2 repeaters (FB2) on 154.175. All of the UHF channels (4xx) appear to be link freqs (point to point).

Not finding any fcc listings for 452.95. maybe license has expired - ????

----------------------------------

more bonus points

Voting Comparators and Remote / Satellite / Voting Receivers - info on remote receivers
 
Last edited:

kevind963

Newbie
Joined
Jun 22, 2012
Messages
4
Okay, I think I am with you so far. Some more insight. Dispatch is in Derry the next town over (Location #6). I also essentially have line of sight to Loc #1 where they have a very large antenna (center of town on a hill).

So should I try tuning a different frequency? Maybe 460.3375?

And yeah, seems like they have some issue using 452.95. I can't even find any expired licenses.

Thanks for your help!
 

ecps92

Member
Joined
Jul 8, 2002
Messages
10,535
Location
Taxachusetts
Think of the UHF as a remote RX back to Dispatch.
Some agencies use "Copper Pairs" aka land-line connections, other use Microwave and then some still use UHF/VHF linking.

Why you don't hear dispatch is to keep the Radio Console from feeding back into itself with audio, when Dispatch keys up, it needs to MUTE itself.

So in a nutshell, if you want to hear it ALL, use the VHF to hear Dispatch and the UHF to hear the portables on the far side of town

Hopr this helps clear out the confuzzlement
Thanks for your help! Sorry for not getting back to this sooner but I wanted to play around with some settings and make sure I knew exactly what was happening.

What I found is that 452.9250 does not contain any of the audio from dispatch including tones. Only 154.17500 includes audio from the dispatcher. 452.9250 only has audio from firefighter portables and vehicles.

I have attached a file of the "static" I was trying to describe. The recording is immediately following a dispatch tone on 154.17500. Instead of going back to 154.17500 to listen to the dispatcher the scanner went to 452.9250 and the dispatch audio was missed.

Like I said, I'm really new at this so I can't answer the VHF/UHF question. But does the recording sound like the "Tone Remote tone" (I don't know what that is either)?

Any help or advice would be very much appreciated! Thank you!
 

zerg901

Member
Premium Subscriber
Joined
Apr 19, 2005
Messages
2,675
Location
Arlington MA
kevind963 - I suspect that Windham FD is doing 99% of their messaging on 154.175. But if they have a working fire, onscene units might switch over to 154.28. This is typical for many NH fire depts.

You might hear the UHF links repeating/relaying traffic from/to 154.175, 154.28, 154.13 Derry, 154.19 County, 154.16 regional, etc. All of the UHF links might be set up to relay traffic from the high spots in Windham to the Derry dispatch office.
 

zerg901

Member
Premium Subscriber
Joined
Apr 19, 2005
Messages
2,675
Location
Arlington MA
hey hey hey - Windham Fire has a new official live scanner audio feed - Windham Fire Live Audio Feed

I used to be able to heard Windham FD over the air - iirc they were loud and clear on 154.175 - let me plug them in and see if I can hear them today
 

zerg901

Member
Premium Subscriber
Joined
Apr 19, 2005
Messages
2,675
Location
Arlington MA
Listening via radio, I can hear the dispatcher on 154.175 (PL 146.2) but not the field units. Listening via Broadcastify, both the dispatcher and the field units are being heard. So apparently Windham FD is not using a repeater (FB2) on 154.175 at this time.

Note - the radio system might also involve links via landlines ('copper wire'), microwave, and Internet.

Bottom line - listening to 154.175 should get you most of the action. Sometimes there might be an advantage to listening to some of the UHF links. For major incidents, onscene units might switch to 154.28, a Derry fireground channel, or a Rockingham County fireground channel. (If you can figure out exactly what they do - please let us know. )
 

kevind963

Newbie
Joined
Jun 22, 2012
Messages
4
I've been listening to both 154.17500 and 452.92500. I've got the settings adjusted on my scanner so the problem I described occurs much less frequently and I hear both dispatch and field units.

There was a working fire last night (unfortunately I was not there to adjust settings) but they switched over to an interop channel V21.
 

zerg901

Member
Premium Subscriber
Joined
Apr 19, 2005
Messages
2,675
Location
Arlington MA
VFire 21 - 154.28 - National Interoperability Scanner Frequencies and Radio Frequency Reference - as we figured

Maybe you can quickly check the UHF channels whenever you hear Windham FD operating on 154.175. (A $25 Baofeng radio can be real handy for doing that). Some of the UHF channels might only be used as backup links. Some UHF channels might only be used to connect the Derry dispatch office to the Windham system. (You can see that in the FCC ULS info - some UHF xmit sites are in Derry only). Some of the UHF links might only carry traffic from 154.28 or 154.19.

Sleuthing everything out might take a while. And maybe no one cares very much about the info. But if you have some time to kill - "aint no puzzle like a radio puzzle". Take care. Peter Sz
 
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