eHam Forums => Emergency Communications => Topic started by: BENHA on December 18, 2006, 09:13:47 AM

Title: Airband Tx?
Post by: BENHA on December 18, 2006, 09:13:47 AM
As an end-of-year 'life review' item, I'm doing a little work to improve my emergency preparedness situation.

One of the things that occurred to me as I was scurrying around putting firestarters and a jacket in the trunk of my car was that it would be nice to upgrade my HT to a unit that, _only_in_an_emergency_ would be capable of broadcasting on airband frequencies to summon help.

Line of sight to a passing airliner seems a lot more reliable than finding someone in my area on 2m or 440.

When I started looking into this, it doesn't seem there are any good options.  The only radio I could find (a Vertex) is discontinued and gets pretty crummy reviews.  Everything else seems to be capable of being modified  for Rx, but not Tx - which doesn't help much if you're stranded.

Before you start:  two radios is not the answer I'm looking for.  I want to cut down on weight / volume / hassle.  I understand the legal issues, too.

Anyway, before giving up, I thought I'd see if anyone out there knows of a HT I didn't find that would solve my problem.


Title: Airband Tx?
Post by: KG4RUL on December 18, 2006, 09:57:37 AM
First, there has to be an airliner passing over - then you have to be on the particular en-route frequencie(s) they are currently using.  There is also the possiblity that you are near enough to an air traffic control facility or tower that you could use the approach, departure or ground frequencies.  Or, if you are near enough to an uncontrolled airport there is always the unicom.  Of course you could just simply transmit on the guard frequency and get yourself into a huge amount of trouble.  Perhaps there are no radios that can do this because it is such a bad idea?

Title: Airband Tx?
Post by: BENHA on December 18, 2006, 10:45:18 AM
If I'm stranded in the middle of nowhere in a huge amount of trouble, I'm less concerned with getting myself INTO a huge amount of trouble, and more concerned with getting myself OUT.

I'm guessing James Kim would happily have suffered the wrath of the FCC, the US Military, the AOPA, the FAA, and a swift kick in the butt from George W Bush himself, to be alive and safe with his family, instead of lost and dead in the mountains.

From my perspective, it's never a bad idea to equip oneself to stay alive.  If you know and respect "the rules," choosing to break them only in a true Mayday situation it seems to me you're not hurting anyone.

Just a thought.


Title: Airband Tx?
Post by: KG4RUL on December 18, 2006, 12:45:49 PM
Benha, you missed the point - Are you going to carry a list of aircraft frequencies for the region you are traveling in or just a bundle of en-route, WAC and high altiude charts to check for frequencies.  This ain't as simple as fire up the rig, key up, yell MAYDAY and someone sends the cavalry!  You have to send on a frequency where someone is listening.

I suppose you could also carry a few PSB and trunking radios, a marine radio, CB radios, and anything else that MIGHT be useful.

If you are serious about being able to get help you may have to spend some bucks for something like this:

The McMurdo Pains Wessex Fastfind Personal Locator Beacon alerts rescuers in an emergency. The personal location beacon signals a satellite which notifies rescue services and transmits a 121.5 MHz signal that searchers can use to home in on your position. Never be too far from help with the McMurdo Pains Wessex Fastfind Personal Locator Beacon.

    * 121.5MHz homing frequency allows rescuers to find exact position
    * Battery life of 24 operating hours and storage for 5 years
    * Sleek and compact design
    * Complete with lanyard and designer carry case
    * User replaceable battery packs available in -20º C and -40º C/F
    * Comes with -20º C battery pack
    * Perfect for boaters, hikers, campers, fisherman, and skiers
    * Comes with ourBestPrice Shopping Guarantee

LENGTH: 6 in.
WIDTH: 3 in.
With -20º C battery pack: 2.1 in
With -40º C/F battery pack: 2.4 in.

Title: Airband Tx?
Post by: KE4SKY on December 18, 2006, 01:09:05 PM
If you will be in a wilderness area and want a distress signal you don't want a 2m ham rig, you want an EPIRB.

Title: Airband Tx?
Post by: BENHA on December 18, 2006, 03:03:21 PM
Now those are interesting.  Expensive, but interesting.

Thanks for the heads up.

Title: Airband Tx?
Post by: KE4SKY on December 20, 2006, 05:12:18 AM
A Globalstar sat phone costs less ($695) than most public safety portables, and is very affordable if you have a genuine need for it.

Title: Airband Tx?
Post by: K2GW on December 20, 2006, 07:11:38 AM
Since the advent of ELT's with their high false alarm rate, most airliners no longer routinely listen to 121.5 MHz.  A personal locator beacon (an ELT or EPIRB for hikers) to activate the SARSAT system is your best bet.


Gary, K2GW

Title: Airband Tx?
Post by: W7ATC on December 20, 2006, 05:12:08 PM
aside from the radio you mentioned (vertex spirit 700) I don't know of anything.

As for the idea of carrying an air capable radio, It's not as bad as others make it seem.

Center freqs usually cover a pretty large area, especially out west. With 2 or 3 programmed in, you can usually hear a plane every few minutes even off peak.

Title: Airband Tx?
Post by: KC9EIZ on December 20, 2006, 07:22:10 PM
I own 2 of the VXA-700 and the reviews do not even come close to the actual capabilities of the radios - in short they have been given a bad rap by what I perceive as a group of “malcontents” who either don’t want aviators to have amateur capabilities or amateurs to have aviation capabilities - the 700's are very, very sophisticated instruments that are not your run of the mill HT’s - several weeks ago a pilot I know called me while flying at 34,000 feet 150 miles from my home on his HT with the standard “rubber ducky” and after 30 seconds of conversation cut his power to .5 watt and we spoke for another 3 minutes - not only James Kim but the person in the Utah badlands who had to cut off his hand and countless others who would have / could have benefitted from the ability to call for help - I’ll take a chewing out from the FCC or FAA over losing my life..........

Title: Airband Tx?
Post by: WW5AA on December 22, 2006, 10:06:41 AM
Anyone can transmit anywhere if it is a true life and death situation. No rules violation! I routinely work 2 meters from my hand held at 5 watts in my Piper Tomahawk (photo on QRZ). Two to 300 miles at 10,000 feet is not uncommon.

73, de Lindy

Title: Airband Tx?
Post by: KB1LKR on December 23, 2006, 01:46:17 PM
Infinitely superior, at least on this planet, would be a Manually activated 406/121.5 MHz PLB (personnel Locating Beacon) essentially a land based EPIRB, preferably w/ GPS. It communicates w/ satellites on a 406 Mhz and has a 121.5 MHz homing beacon.

Note though:
Under federal law, 14USC88, knowingly and willfully transmitting a hoax distress call is a felony. It is punishable by up to six years in prison, a $250,000 fine, and restitution to the rescue agency for all costs incurred responding to the distress.

If you purchase a new or a used 406 MHz EPIRB, ELT or PLB you MUST register it with NOAA. If you change your boat, your address, or your primary phone number, you MUST re-register your location beacon with NOAA. If you sell your beacon, make sure the purchaser re-registers the beacon, or you may be called by the Coast Guard (EPIRB), Civil Air Patrol (ELT) or local Search and Rescue team (PLB) if it later becomes activated.

SARSAT Beacon Registration
E/SP3, Rm 3320, FB-4
5200 Auth Road
Suitland MD 20746-4304


Title: Airband Tx?
Post by: KE4DRN on December 25, 2006, 10:03:09 AM

easy for things to go from bad to worse very quickly.

for daily use, you can't beat your 2m ht with an
external antenna (or your mobile radio) and a current repeater journal or arrl repeater guide.

You could hit a repeater and your chances of getting help would be a lot better then using avation bands.

Even the newer handhelds that cover CB bands are very reasonable and small in size for the car or backpack.

if I ever decide to climb a mountain then I'm bringing some experienced climbers with me and a sat phone.

you are right about extended reception, that is the easy part, tx out of the band specs for a radio is harder to do with the way these radios are designed and built today.

73 james

Title: Airband Tx?
Post by: W7STS on December 27, 2006, 03:57:23 AM
I routinely carry an airband when in the back country of Arizona.  Being a pilot, it was easy for me to justify.  Also being a pilot, it gives me the knowledge to know what freq's are likely to be in use, however, in a real emergency situation in a place where I wasn't sure of the Freqs, I would let the radio scan for a while, and when I got a hit, I'd give that a/c a call figuring it's line of site.  It shouldn't take more than a couple tries to get a response.

I am not sure I want the bulk of an ELT is, and frankly, for me, the justification is that I would want to carry it in my flight bag anyway.  

A dual purpose VHF/FM and Airband seems like a good tool for anyone with enough common sense to operate it.

Rick Aldom - W7STS
Arizona Section Emergency Coordinator

Title: Airband Tx?
Post by: KC8VWM on January 09, 2007, 08:40:43 PM

If you are serious about an emergency communication radio then there is no reason why you shouldn't try to make the most out of your intentions and maximize on your success rate of making a contact during an emergency scenerio.

Personally I would forget about using a 5 watt HT and rubber duck on the Airband frequencies. I would rather pack a fully capable and compact DC to Daylight HF rig like an FT 857D that is capable of transmitting 100 watts into an easily deployable ready made antenna wire. You don't need to blast out 100 watts to achieve communication either, but it sure is comforting to know that the capability  is "there" if you need it.


The whole thing would fit nicely inside a camera bag, waterproof ammo can etc. and is about the same size and weight as many marine grade EPIRB's or even some sat phones.

Sat phones are nice but if it's a particularly dark cloudy day, then connectivity can sometimes be unreliable. this was demonstrated in many instances during Katrina. It was reported that Military satphones didn't always get through.
HF on the other hand would propagate signals a 1000 miles away regardless of the weather during situations when VHF transceivers would be dead in the water.

As far as a portable power source to operate the equipment is concerned it wouldn't be much different than an HT or sat phone really. A small SLA battery, a homemade wiring harness to connect to an available car battery (even when half dead will work) or maybe you can make it real elaborate by including a roll up solar panel in the communication toolbox for increasing your operating time.

Many options are available. I just wouldn't limit yourself to using one particular band or limit yourself to an EPIRB or other similar device. Sure these devices "work", but it sure is nice to actually "talk" to someone to inform them of your position and/or explain your predicament. Signal locator devices can take days in some instances.

For example, I think if I were stranded on a desert island scenario :) I would want a full compliment of communication capabilities at my fingertips.Probobly would cost that much more money when compared to other "limited" options in the long run either.

Also don't forget to pack other "visual" signalling devices. A battery operated strobe a smoke signal, signals flare etc. would help people "hone" in on your specific position when they get close.

Lot's to consider, the important thing is to think it through and you won't become a victim of yourself.

73 de Charles - KC8VWM

Title: Airband Tx?
Post by: AI4KK on January 10, 2007, 08:53:45 AM
I like the idea of a DC-daylight rig that lets you set the mode independently of the frequency, thus giving you airband capability if you truly need it plus a ton of other options as well including HF, CB, and FRS. I personally would go for something like the FT-817 if I had to backpack it. You can always whip together a resonant dipole for almost any frequency you can dream of, including 121.5 which is still monitored by many pilots out of habit if nothing else even though ELTs are rapidly going the way of dinosaurs. EPIRBs, which are the same thing on boats, have already been banned on 121.5 due to the unreliability and high incidence of false alarms.

As for alternate signaling methods, don't forget signalling mirrors as they can be seen a VERY long way off. Ignore the folks that say "use a CD" unless that is your absolute last-ditch option (they're useless as they don't reflect light in a straight aimable beam, they just look shiny) and get a good military survival mirror. They're not expensive and the aiming grid on the back makes it much easier to put your spot of light directly on the target.

AI4KK / FL CAP 1019

Title: Airband Tx?
Post by: KE4SKY on January 11, 2007, 01:19:20 PM
A signal mirror is an essential piece of gear for any go kit.  The laminated glass military versions are the best, but the better grade plastic ones such as Starflash, ACR and BCB are  Coast Guard approved and are much lighter.  The latter should be kept in a protective cover when not in use.  

Some useful links:

Title: Airband Tx?
Post by: K2GW on January 12, 2007, 06:06:06 AM
I concur. When I use to fly SAR missions, we found that the detection range for a signal mirror could be up to 20 miles. And it worked no matter what frequency we were listening to ;-)

Here's a simple way to use any mirror as a signal mirror:

1. Hold the mirror next to your eye.
2. Extend your other arm and make a Vee with your pointer and index fingers.
3. Move your "finger vee" until it straddles your intended target.
4. Adjust the mirror until the sun's flash is hitting your "finger Vee". It's now also hitting your intended target.
5. Don't worry about sending SOS. Just keep hitting the plane with it. Most other single point sun reflections from puddles, etc. won't follow the plane. Continuous flashing from one point is an obvious signal.


Gary Wilson, K2GW
(Former Instructor, USCG/USAF National SAR School.  

Title: Airband Tx?
Post by: KC0ZBQ on January 21, 2007, 11:48:12 AM
What I think is interesting is that the emergency frequency of 121.5 isn't used by search and rescue to communicate.

Having an airband radio, such as the Icom IC-A24, works for backcountry since many pilots monitor 121.5 plus the general control frequencies are published and you could use them if need be. Of course, ONLY in an emergency may you do so. The FCC DOES NOT give license for people to use the airband outside of ATC facilities, aircraft, and some limited balloon chaser crews.

As a pilot I have an aviation radio but as someone else said, it is far better to spend the money on a personal locator beacon that can give better than a 99.9% success rate of signaling for help and getting that help to you. They are GPS units that can tell rescuers your location to within feet and do so within a few minutes of turning on the transmitter.

Avaition radios are a nice idea but search crews usually use 2-meter radios and a personal beacon is a far better choice.

Title: Airband Tx?
Post by: W5HTW on January 24, 2007, 07:35:28 PM
I hate to say it, but when I was flying I did not monitor 121.5!  IF VFR I monitored multicom, 123.000, plus one of the local Unicom freqs.  If cross country, I monitored with one set the FSS and with the other local airports according to the charts.  I think very few private pilots monitor 121.5

Different story if that pilot happens to be in an SAR mission. Then he is monitoring 121.5.  But no, it is not used for communication.  Just for monitoring for an ELT.  

Part of the problem with ham-air band radios is air band radios cannot be adjustable from the front panel except for channel selector or buttons, and volume and squelch, pretty much like public safety radios, except air band can dial up a lot more frequencies.  Ham radios, on the other hand, can go between channels, if desired, and that capability is not found in air radios.

The other is air band is AM.  Lots of ham radios include an AM detector for listening, but very few handhelds contain AM transmit circuitry.  None I am aware of at the moment.  

Still, were I in the back country the first choice for me would be a sat phone.  Second choice would be an ELT so I can hit the satellites.  Third choice would be an air band handheld, I guess, though I may would opt for a 2 meter handheld instead.  And of course, I would have a cell phone, for sure, so if I was within range of a cell tower (and most places, even remote ones on hill tops are) I would just use the phone.  

True a small CW rig could be easily handled.  And I have used CW for an emergency, many years ago. But we are approaching a point where no one would know what was being said.  Perhaps a very QRP SSB rig?  


Title: Airband Tx?
Post by: W7CLC on February 20, 2007, 12:45:56 PM
Military aircraft routinely monitor 121.5 and 243.0.  The larger airplanes have more radios than the fighters.  In heavy airlifters we had two UHF and two VHF, so we monitored both guard freqs.

Our survival vests had a single HH radio that transmitted voice and beacon on 121.5 and 243.0, so you might look for surplus military gear.

Title: Airband Tx?
Post by: DA2KI on February 28, 2007, 12:05:48 PM
This was a dead thread the minute it was posted.  The request was for an Amateur Radio single or dual-band HT that could be "modified" to transmit on the VHF aeronautical band.  The poster did not want to carry a separate HT designed to operate on aviation frequencies.

Even if you found such an Amateur Radio HT that would operate that low below the 2-meter band, it would only transmit in FM mode.  The aeronautical band is AM.  This is a no-go regardless of whether you can get the Amateur Radio HT to transmit on the aviation frequencies.

The only possible solution would be a modified HF/VHF/UHF backpack type radio.  But the poster specified that he wanted a HT.

Title: Airband Tx?
Post by: WA4DQS on September 19, 2007, 11:49:25 AM
I've been a participant/member of a flying & skydiving club for years, and own a few airband radios including the Vertex Spirit crossband HT.

An airband HT can be peace of mind for the emcomm crowd, but not likely ever to be needed.

That said...

In the 1990's I had to handle a life-threatening emergency (critically injured off-road motorcyclist) requiring the alternating use of my 2 meter HT, and air band HT to make an emergency call, then help direct a medevac helicopter to our remote campsite. (cell phones didn't work out there) The VXA 700 would have been handy that day.

Our flying club later installed a 36 watt airband crew vehicle two-way in one of our trucks, as a very expensive peace-of-mind-back-up option that was inspired by another emergency. But that's another story...

Google around. There's plenty of good pilot airband HT's out there -- Icom, Yaesu, etc. The Sporty's SP-200 is pretty inexpensive, uses 8 AA batteries, so it has that practical value. But the battery pack is a bit flimsy IMHO.

If you get a used VXA 700, call Vertex and order an spare crossband HT rubber ducky, but also carry separate 2m and airband duckies.

And if you're going to carry an airband, learn the frequecy allocation of that spectrum and stay off it unless the crap hits the fan -- hard. 99.9% of the time there's a better solution than trying to flag down an aircraft.