What radio bands to monitor?

Posted by: Mark_R

What radio bands to monitor? - 05/28/15 11:02 PM

While poking around for additioal information preps, I discovered there are a lot more RF bands in use then I initially thought. Between REACT, ARRL/ARES, RACES, and the local emergency services, I'm seeing: HF and above ham bands, MURS, CB, FRS/GMRS, and LMR. I'm hoping that listening in on these channels could provide information well before it percolatesw down to the broadcast AM radio emergency stations.

Is there any real advantage to monitoring these, and one better then the others for this?

I looked at, but I'm not interested in ATM, at getting a ham or GMRS licence.
Posted by: LesSnyder

Re: What radio bands to monitor? - 05/29/15 01:16 AM

Mark... for me, naturally, the more options you have for receiving timely information, the better you can make a decision on how to react in case of an emergency...as an Air Force Radio Traffic Analyst, my job was to perform analysis of intercepted communication, and issue any tactical condition warnings or critical time restrained intelligence reports to higher echelons ...call sign, frequency, and operating schedule analysis was a necessary part of the job... on a practical aspect, living on the central Gulf Coast of Florida, I follow the Crown Weather Service Tropical reports, I have two SAME weather alert radios for tornado alerts, a portable digital TV with folding dipole rabbit ear antenna for local Doppler radar that is GPS linked, as well as an old Grundig crank radio with which during the 2004 9 day power outage listened to the BBC World Service... I'm not sure the BBC still broadcast on HF...it is my understanding that the LDS net was very effective during Katrina...FEMA frequencies are on the net.. many local VHF emergency nets in my area are encrypted...
Posted by: unimogbert

Re: What radio bands to monitor? - 05/29/15 02:40 AM

I think monitoring first responder channels is the way to go for the earliest warnings in your local area.

Most other stuff comes thru channels that have to be "activated" by the PIO machines of agencies.


When the big floods hit Colorado 2 years ago I heard, in real time during my early morning commute, the fireman who'd gone up a canyon to check on something as he was reporting his situation from up a tree using a handheld radio. Flood waters had come down and started washing his truck away so he climbed a tree.
He carefully gave dispatch his name, agency and home phone number in case he drowned. (!)

From that I had a pretty good idea that there was badness going on in the canyons.

News stations started doing gee-whiz coverage a few hours later.

When it was time to bail out of work and go home, I tried to use the scanner to figure out what routes were open. That idea failed. Every channel was utterly clogged with continuous traffic since the flooding was so widespread across the area I needed to transit to get home.

Only my personal knowledge of multiple back road routes home got me there before some of the bridges washed away.
Posted by: AKSAR

Re: What radio bands to monitor? - 05/29/15 08:48 AM

Originally Posted By: unimogbert
I think monitoring first responder channels is the way to go for the earliest warnings in your local area.
Enjoy it while you can. The trend in many areas seems to be towards police, fire, and EMS going to encrypted digital communications.
Posted by: unimogbert

Re: What radio bands to monitor? - 05/29/15 12:42 PM

Encryption - yep.
My town has gone there. The next town in my commute has encrypted everything but dispatch.
But the next 2 towns and the 2 counties and the State and the snowplows haven't (yet).
Posted by: Mark_R

Re: What radio bands to monitor? - 05/29/15 02:33 PM

The bulk of the first responders are in the 144-174MHz LMR bands. I have no idea if they are encrypted. I would imagine that LE is, but ARES/RACES isn't. Everything else is a flip of the coin.
Posted by: unimogbert

Re: What radio bands to monitor? - 05/29/15 02:49 PM

The website RadioReference is the place to go to find out frequencies and agencies for just about anywhere in the US.
And there are notes about encryption and sometimes pending system changes.

Most of Colorado first responders are on an 800 Mhz trunked system. Some agencies haven't converted yet and others keep the VHF freqs as backup for areas where the trunked system doesn't have coverage. But the dominant system in Colorado is the 800 Mhz DTRS.

Each area is different so it would pay to investigate one's area closely rather than relying on general internet advice.

ARES/RACES in the ham bands cannot, by regulation, be encrypted.
Posted by: Mark_R

Re: What radio bands to monitor? - 05/29/15 06:43 PM

Nuts. Most of the emergency services have switched to 700 MHz P25 or 800 MHz Motorola trunked bands, but kept the VHF/UHF bands as backups. That means a trunk tracking scanner ($$$). The civilian emergency services (CERT, REACT, ARES/RACES) are all on the 2M or 70cm ham bands with CTCSS tones.

Is there any real value in monitoring those?

Also, does anybody know a quick way to boost FM radio reception? I can pick up AM signals clearly from 80 miles out, but FM is less then half that.
Posted by: LesSnyder

Re: What radio bands to monitor? - 05/29/15 08:09 PM

frequency modulated (FM) voice communications on VHF and higher frequencies signals are line of sight as they don't readily bounce off the ionosphere (specialized military transceivers bounce off ionized tails of micro meteors) and "skip" as the lower frequency HF signals do...they travel on into Space... due to the curvature of the Earth you may not be actually inside the cone of coverage of the transmitter's antenna... your receiving antenna must be elevated high enough to do so... the signal strength inside the cone can be increased by a Yagi multi element di-pole antenna, where each of the parallel elements induces a little more signal voltage and is very directional...and there are amplifiers that boost signal...

I don't know your age, but pre cable TV antennas were Yagi... with several distinct lengths of elements pre cut for a particular TV channel frequency (ABC,CBS,NBC)... and a smaller 8 or so element nose for the UHF/VHF networks... an antenna rotor was used to orient them
Posted by: Tjin

Re: What radio bands to monitor? - 05/29/15 08:47 PM

Not sure if it's used in the states, but where I life the radio's are encrypted, but the pagers are open. If you know how to read the pager messages you should know a lot about the incident and since you can see them on your computer screen you can also see the older messages, giving you a nice overview. You can also search by location and rescue service.

I know a lot of proffesionals grab there computers and have a look there pager messages there, since there are many open websites which will also automatically point the location on google maps. Also opening the link on you browser is quicker dan browsing on the pagers.
Posted by: bws48

Re: What radio bands to monitor? - 05/29/15 09:00 PM

Excellent explanation!

For VHF, height and the proper antenna design are key.

But for which radio bands to monitor, the individual circumstances can give you reception while someone close to you cannot receive anything. And even with FM, strange (but uncommon) atmospherics can give you reception even though you are way out of line of sight from the transmitter (say 50 to 70 miles). I personally have heard VHF signals from hundreds of miles away; not predictably, but it happens.

While I think there must be better versions today, at home I still have an ancient Zenith multi-band radio (AM, FM and multiple HF and other bands) and a small Grundig multi-band radio.

In a really bad scenario, I don't think VHF FM will be useful: IMO, HF frequencies will be key. They have global reach without satellites, cable or repeaters. All you need is a transmitter and a receiver set to the right frequencies.

In case you are interested in the long range possibilities of HF in a crisis situation, it appears (reasonably possible and likely) that HF voice transmissions from Amelia Earhart were received by a young girl (Betty), in Florida. USA, after Earhart made a safe landing on Howland Island's reef. See: http://tighar.org/Projects/Earhart/Archives/Archivessubject.html
and scroll down to "radio distress calls" for several articles discussing Betty's evidence.
Posted by: Mark_R

Re: What radio bands to monitor? - 05/29/15 09:31 PM

I'm more interested in local situational awareness, without waiting the hour plus for the radio to broadcast it, then MF or HF skips off of the ionosphere. Besides, anybody who was unlucky enough to pick me up would have to wade through my painfully slow morse code.

-.- -. --- .-- .-- .... .- - .. -- . .- -. ..--..
Posted by: Tom_L

Re: What radio bands to monitor? - 05/29/15 10:20 PM

Originally Posted By: bws48
In a really bad scenario, I don't think VHF FM will be useful: IMO, HF frequencies will be key. They have global reach without satellites, cable or repeaters. All you need is a transmitter and a receiver set to the right frequencies.


True, however, HF reception is extremely dependent on solar activity and ionospheric conditions. These vary a lot and in fact, have not been all that great recently (and for a few years already). So that is one thing that needs to be taken into account.

As far as radio in general, antenna is key in any band, regardless of your basic setup. In some ways, VHF/UHF is easier to work with because the proper antenna length is short and easy to manage. If you can get to a higher altitude, hopefully with a clear field of view, it will improve reception by an incredible margin. Even a cheap, low powered 0.5W PMR/FRS radio can reach out well beyond 50 miles under ideal conditions. In fact, the current PMR long-distance record is 333 miles. (Not that I would ever count on that sort of performance, but it does happen.)

HF on the other hand requires a very long antenna to work well. Now, even a 100ft spool of wire suspended on poles or trees will do fine for starters, but it is not very practical if you're on the move. So for really good long range performance HF reception works best with a stationary setup. And alas, only at night. During the daylight hours a basic multiband/HF receiver might have a pretty hard time picking up anything useful.
Posted by: LesSnyder

Re: What radio bands to monitor? - 05/30/15 12:27 AM

re: antennas., AN/FLR9... gratuitous picture of my old duty station, 6922nd Security Group, Clark AFB, Philippines...once upon a time these HF direction finding stations ringed the Bear and Dragon... most have been dismantled since the end of the cold war



Posted by: Mark_R

Re: What radio bands to monitor? - 05/30/15 12:59 AM

Originally Posted By: Tom_L


True, however, HF reception is extremely dependent on solar activity and ionospheric conditions. These vary a lot and in fact, have not been all that great recently (and for a few years already). So that is one thing that needs to be taken into account.


We're coming off of the peak of the 11 year sunspot cycle. Could that be monkeying with the ionosphere conditions?

Posted by: chaosmagnet

Re: What radio bands to monitor? - 05/30/15 03:08 AM

Originally Posted By: LesSnyder
I don't know your age, but pre cable TV antennas were Yagi... with several distinct lengths of elements pre cut for a particular TV channel frequency (ABC,CBS,NBC)... and a smaller 8 or so element nose for the UHF/VHF networks... an antenna rotor was used to orient them


That's not exactly how a Yagi works, there's a really good article at http://en.m.wikipedia.org/wiki/Yagi-Uda_antenna .
Posted by: Nomad

Re: What radio bands to monitor? - 05/30/15 03:14 PM

Here is a link from the FCC that shows all licensed station within a user specified distance from a user supplied location. Insert your location (lat/lon) and try 25 miles for a starter.

http://fjallfoss.fcc.gov/General_Menu_Re...;wild_select=on

It is a bit of a technical babble but you can get a good idea of the interesting sites in your area and the type of gear you will need to monitor them.

If you are technically inclined, I suggest one of the software defined radio dongles that plug into your computer. Cheap, $20 or so. They provide a "waterfall" display of a wide segment of frequencies. You click on one and it decodes it. CW, RTTY, PSK, P25 (common digital audio used in most public service systems) and much much more. If you are an old tyme radio guy, this will really change your understanding of radio. Very impressive gadget.

Some really good educational stuff out there about software defined radio. Once you get up to speed (not hard) with this technology you will never even consider getting a dedicated scanner.

Most only work 30Mhz to 2ghz. Need to play games if you want below 30Mhz.

Posted by: bws48

Re: What radio bands to monitor? - 05/30/15 05:23 PM

Originally Posted By: LesSnyder
re: antennas., AN/FLR9... gratuitous picture of my old duty station, 6922nd Security Group, Clark AFB, Philippines...once upon a time these HF direction finding stations ringed the Bear and Dragon... most have been dismantled since the end of the cold war


And I was a USASA Field Station Augsburg (mid-70's), Gablingen Kaserne, Augsburg Germany (aka "Home of the Professionals"). We also had the AN/FLR-9. photo here:

http://upload.wikimedia.org/wikipedia/commons/2/2d/Abh%C3%B6ranlage_Gablingen.JPG

One very vivid memory I have is driving with one of the maintenance WO's into the center ring in his car with the car radio on. Great reception outside the ring, none at all after getting past the inner ring. These things really sucked up the RF energy.
Posted by: Russ

Re: What radio bands to monitor? - 05/30/15 06:16 PM

Thanks Nomad, this sounds interesting. Do you have a link for a "software defined radio dongle" you recommend.
Posted by: Mark_R

Re: What radio bands to monitor? - 05/31/15 02:22 AM

I think he's talking about something like these.
www.amazon.com/RTL-SDR-Blog-RTL2832U-Software-Telescopic/dp/B00QFCNNV0

I'm not sure how much good it would do while moving due to battery life of a laptop. But while stationary, and if it could handle CTCSS tones and trunking, it would provide critical information well ahead of the radio.
Posted by: Tom_L

Re: What radio bands to monitor? - 05/31/15 12:26 PM

Originally Posted By: Mark_R
We're coming off of the peak of the 11 year sunspot cycle. Could that be monkeying with the ionosphere conditions?


Absolutely. HF radio propagation is a pretty complex matter, though. Lots of factors involved - a couple of useful links (hopefully not too technical):

http://www.radio-electronics.com/info/propagation/ionospheric/hf-propagation-basics.php

http://www.radio-electronics.com/info/pr...lar-indices.php
Posted by: Nomad

Re: What radio bands to monitor? - 06/02/15 02:37 PM

Originally Posted By: Mark_R
I think he's talking about something like these.
www.amazon.com/RTL-SDR-Blog-RTL2832U-Software-Telescopic/dp/B00QFCNNV0


Yep, that is a good example. Also read the blog from the vendor. Then google SDR Radio and look for youtube videos.

I did not include links because they change so fast. However google (or duckduckgo.com) is your friend.

Yes, it has a steep learning curve, but if you have the technical background and interest you will find it to be an amazzzzzzing gadget.