No more AM air RX on 2M mobiles?
Meadeball (K4CMD)
on
April 21, 2003
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A year ago I went shopping to replace the IC-2000H 2M mobile rig I used as a 2M base rig for the shack after it was killed in a lightning strike. Naturally, having been very satisfied with the 2000H, I started by looking at its replacement, the IC-2100H.
I was all set to buy one and drove up to my "local" HRO store (100 miles away) to make the purchase. But after playing with the demo rig for a few minutes I lost all interest. Why? A big "standard" feature that I used to take for granted was gone from the successor -- no more AM aircraft receive!
Ten years ago, it was standard across-the-board among manufacturers to offer 2M mobiles that received from 118 to 174 MHz. Now, after looking at other offerings from Yaesu and others, I'm finding that the standard has been raised to 136 to 174 MHz, completely eliminating the AM aircraft band. Many of the current crop of 2M HTs also have lost this capability.
Now certainly I realize that a rig's ability to receive the air band has nothing to do with amateur radio, but since I live on the western and busiest approach to my local airport, I had become a sort of aircraft monitoring buff -- a hobby within a hobby that the manufacturers themselves instilled within me and countless other hams by including it among their radios' standard features for years.
Before anyone slams me for expecting "too much" from a 2M rig, let me point out that many hams take for granted their rigs' capability to receive NOAA weather radio broadcasts -- even though there's no requirement that they have to offer receive capability up to and above 162 MHz in a rig designed for 144-148 MHz use.
So far I've found only two 2M rigs currently on the market that still offer AM air band reception -- one from Alinco and one from Kenwood, and the Kenwood (TM-261) happens to have been on the market for about 10 years. Icom and Yaesu no longer offer a 2M mobile rig or a 2M HT that receives the 118-136 MHz segment. I see this as the loss of a feature that the manufacturers themselves caused hams (at least those who've been around for a decade or so) to expect in a 2M radio.
For now the spot on my shelf in my shack is bare. I've purchased a tri-band HT with "DC to light" receive capability, and that's doing the job for now. But it sure would be nice for all manufacturers to offer what they used to offer so some of us air band junkies could have more to choose between than a mobile designed for packet and a radio with decade-old features.
73,
Meade K4CMD
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No more AM air RX on 2M mobiles?
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by K7IHC on April 21, 2003
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For mobile/HT ops in my area, I prefer a VHF/UHF dual-bander. Most of the current dual-banders have the VHF AM aircraft band receive. I usually use a scanning receiver (scanner) to monitor the 120 MHz AM aircraft band at home. It can be convenient to have aircraft receive in an amateur H/T (like my Kenwood TH-G71A dual-bander), as you can easily use it in the airport terminal while travelling. It's also convenient to have the capability in my Kenwood dual-band mobile when I go to the airport to pick-up or drop-off someone. It doesn't bother me that my Icom 2100H radio doesn't have the aircraft band. I'll just use one of my scanners or other ham radios that does.
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No more AM air RX on 2M mobiles?
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by K5MAR on April 21, 2003
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Well, I hate to say it, but airband rx is just not a hot ticket item for a majority of hams. If a feature isn't a selling point, then the manufacturers aren't going to spend the money adding it to a FM radio. For those who are interested in aviation monitoring, it's alot simpler to buy a scanner that covers the airband, rather than tying up our 2m rigs. That's what I've done, even though I posess several 2m and 2m/70cm rigs that came with airband rx capability. The scanners are simply better at receiving multiple airband freqs. I have yet to see a ham rig with airband receive that could scan as fast as a dedicated scanner. Sorry, but that's the way it goes in a market-driven business.
Mark Schneider - K5MAR
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No more AM air RX on 2M mobiles?
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by WA8VBX on April 21, 2003
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Does it bother me, no not really but it was/is a nice feature. I live near Detroit Metro Airport, and sometimes while in the shack I would listen to the air traffic as it came and went. Now in response to the other guys and they have a good opinion, I have limited funds and area to put a station so to have another radio (scanner) would be pushing the limit. Also the local PD/FD's here have changed to 800mhz digital so a scanner is basically a useless item now.
But I do have to agree that the radio companies put in features that they think will sell the radio. There are features in my current dual band radio (9600 baud, packet capable) that I will probably never use, and a lot in my HF rig that I won't use.
Buying the tri-band HT with DC to Light I think is a good idea. It might not have the power you wanted but at the same time it is easier to take on a trip, plus you get the ability to listen to HF/Shortwave Broadcast. etc.
I remember when HF rigs were only Ham Freq's and general coverage was a big deal when they first came out, now it is standard, so as the market changes so does what the companies put out, look at the amount of radio's that have come out for QRP/Portable/Backpacking from the big 3. Do they listen to the buyers, probably some, but I think they look at what the current trend is and go from there.
73
Kurt
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RE: No more AM air RX on 2M mobiles?
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by G1YGJ on April 21, 2003
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This is obviously a crafty ploy by the " big boys " to make us buy separate airband radios or scanners, thus making more profit for themselves !!.
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RE: No more AM air RX on 2M mobiles?
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by N8EMR on April 21, 2003
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Icom's new IC-208H has AM air receive, The Alinco DR-135T has am receive. ICOM 207H has it, The new ICOM 2720H , Kenwoods OLD but current model TM-261A has it,
The overly priced TM-D700A has it, The cool blue TM-V7A has it, The Yaesu FT-1500M can do it. So it seems that they have not abandoned air band rx.
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RE: No more AM air RX on 2M mobiles?
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by W3FHW on April 21, 2003
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You may want to consider the yaesu ft8900m. It receives 108 thru 136.975 AM. Of course, it's not only a single band 2 meter rig, but also covers 10 meter FM, 6 meter FM, and 70 centimeter FM. It also has two seperate VFO's for full duplex and it crossband repeats. Diplexer is built in. Currently $390.00 at HRO. I have two 8900's, one mobile and one in the shack. I find it to be a lot of radio for the price.
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No more AM air RX on 2M mobiles?
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by N8VQJ on April 21, 2003
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I could understand this gripe a few years ago when Dual Band rigs were expensive. But now, I can go TODAY to the candy store and pick up a dual band mobile for about 169 (Alinco DR-135T). It has AM aircraft receive. Between the big 4 companies, there are only 5 2m only mobile rigs. Yaesu makes 2 2m Mobile rigs and all of the rest only make one. It's time to go get a dual bander and stop whining! :) My quad band VX-7R can pick up aircraft AM, but the out of band stuff I use is the AM/FM Broadcast band and VHF/UHF TV Audio receive. Shortwave is a bonus. So quit yammering and pick a new rig.
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No more AM air RX on 2M mobiles?
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by K5DVW on April 21, 2003
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I'd be all for eliminating anything outside of the ham bands, especially if it means tighter filtering in the front end. Most wide band VHF/UHF ham equipment I've owned is crap when it comes to intermod performance.
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No more AM air RX on 2M mobiles?
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by KG4SUF on April 21, 2003
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My Kenwood dualband VHF/UHF TH-G71A has wideband receive (with the popular RX mod) from 118-949 MHz.
My Yaesu FT-1500M 2m mobile does not; its RX is 136-174.
But I don't listen to aircraft. :-/
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RE: No more AM air RX on 2M mobiles?
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by W9WHE on April 21, 2003
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Mabey you are just not looking at the right manufacturer. Take a look at Yaesu.
My FT-90 covers AM airband!
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No more AM air RX on 2M mobiles?
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by WA2JJH on April 21, 2003
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I agree with all previous post's.
I remember in 1977, I bought a used 2 meter Heathkit
"Lunchbox" rig. I was all excited to work 2 meters.
I was a new TECH back then. I was 16 years old.
I thought I would have tons of great 2M QSO's.
Big problem, the rig was AM. Did not hear a single signal. Then I tuned up to the repeater freqs. Heard FM audio but had to use slope detection. Had to turn the volume control all the way up. The horrible thing was when the repeater dropped, a piercing sound of super-regenertaive noise would Blast the house.(maybe half as loud as a 747-landing!)
No AM QSO's back then. I would venture 2M AM QSO's are non existant now.
I like having AM to listen to aircraft freqs. Why the airline industry stuck with AM is beyond me!
If I remember correctly, only 25-33% of AM contains
what you want to hear. The rest is wasted carrier and a
identical sideband.
I have also found the RX on AM in handhelds so bad, that one must live within 25 miles of a major airport.
So no AM in 2M rigs is not going to ruin my day.
73 MIKE
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RE: No more AM air RX on 2M mobiles?
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by N5CTI on April 21, 2003
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I'm not sure where you're getting your information, Meade. As indicated by many of the responses above, there are many rigs, such as what you describe, that have AM airband capability. The Yaesu FT-8900 and VX-7R have been mentioned already, and my VX-5R also receives that band.
Look a little closer at the specs on the radios you're investigating. There are quite a few out there that will give you what you're looking for.
73,
Boyd / N5CTI
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RE: No more AM air RX on 2M mobiles?
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by KA0MR on April 21, 2003
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Why would you even consider reception of outside the ham band when contemplating purchasing a radio specifically for where you are allowed to operate.
This is the main reason people complain about intermod on radios that are capable of wideband coverage. I have had these radios and they are all plauged with the same problem. But guess what my Radio Shack HT-202 has never had an ounce of intermod anywher in the 2 meter band. I guess cause it doesn't have this stupid wide band coverage is the reason.
Want to listen to the AM aircraft band buy a wide band scanner and listen to the intermod at 116 to 136 MHz. Want to hear clean signals in the aircraft band buy an aircraft band transciever from Icom or Yaesu or Kenwood. on't hear a squack of intermod in the aircraft band.
Sorry but I don't play my violin for this one.
Bob
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No more AM air RX on 2M mobiles?
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by N6HBJ on April 21, 2003
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I like to listen to the Public Safety band and most dual banders include the 3 public safety bands in them. The problem is that in most of them the UHF portion tops out at 480 mhz but the local police depts use 488+ around here and the ambulance uses 482 mhz so that the extended recieve on those radios does me little good. The low band portion is also limited so I can't listen to what I want.
The simple solution to all of this is to just go out and spend a lousy $150 and buy a SCANNER. Especially if you are talking about a base setup.
Uniden just came out with a 1000 channel trunking scanner with full alpha numerics (no more guessing which department or repeater you are listening to) for about $360. It can also scan the DIGITAL trunking systems if you purchase the additional module for that.
Even Radio Shack has some decent trunk trackers.
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No more AM air RX on 2M mobiles?
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by WA2JJH on April 21, 2003
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You might want to consider the Alino DJ-C5 microsized
dual bander. It can be had for under $100.
It is smaller than many law enforcement body wires.
Lithium battery that will not quit!
Only problem, it is QRP.(300mw) I can reach all my local repeaters DFQ.
It has all the IMOD any other Broadband VHF front end will have. There is also no external antenna jack either.
It is the size of a credit card. It is as about as thin as 15 credit cards.
All metal case. Except for certain motorola's, it is vitualy drop proof.
Like many other posters have said, there are still plenty of dual banders that will cover 110-138 AM.
Abeit poorly!
Scanners are dirt cheap too.
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by KG4YJR on April 21, 2003
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I would almost have to agree G1YGJ. They are about to go digital with our PD/FD too. We have one officer in our club that is testing the new equipment and named off the numerous problems associated with them. Especially when the frequency is busy, you can't tell until you key in. He said you could be getting shot at or getting beat up and when you key in you get the "busy" tone. I sure hope that problem will be fixed before full implementation.
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RE: No more AM air RX on 2M mobiles?
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by WS4V on April 21, 2003
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Get an ICOM 2720H. It has it and is all you need.
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RE: No more AM air RX on 2M mobiles?
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by WB2WIK on April 21, 2003
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AM is still used because it maintains the phase relationship between modulating sidebands and the carrier, which FM does not. How much longer this will be of any service to anyone is another question!
I agree with the other post stating that once you "wideband" the VHF receiver, a lot of performance is lost for certain, with regard to immunity to overload and intermodulation. The 2m rigs having by far the best receivers are the ones which only cover two meters, and have no out-of-band coverage at all.
WB2WIK/6
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by WA2JJH on April 21, 2003
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Maybe the phase differential vs carrier has something to do with IFR fight operation. Or guidence vectoring in an emergency situation.
I am off tangent here. However WB2WIK brings up an
excellent piece of communication trivia I am sure digital schems are in the works.
Getting back to the scope of the thread. Some of the older radio's that had aviation coverage, were modifiable to transmit as well. A very bad idea for a multitude of reasons. Being ILLEGAL and Dangerous are two that come to mind stat.!
The same reasoning applies to CELL phone freqs Hardware blocked! Even the image freqs are blocked!
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No more AM air RX on 2M mobiles?
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by VE6BGM on April 21, 2003
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Not having Air coverage is one reason I haven't purchased some new radios, IE: VX-150. I don't like to have radios coming out of all pockets and vents in the car to monitor freqs. that I like to listen to. Air coverage gives excellent weather coverage of changing condtions, especially with Lightening and Snow storms. For me, it is a big mistake that Air coverage is not included.
73
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RE: No more AM air RX on 2M mobiles?
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by WD4AOG on April 21, 2003
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While I like the convenience of having every conceivable band in one box, such wide-band rigs have to compromise receiver performance in order to cover so many bases. That forces me to spend too much time adjusting the squelch and attenutation on my IC-706mkIIG. Some days I really miss my old IC-22S and it's hot receiver and great intermod rejection.
Newer hams have probably never owned anything BUT wide-banded rigs and don't know what they're missing.
Bottom line? I like AM aircraft receive capability, too but I'd sacrifice it to get a nice tight receiver front end again.
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No more AM air RX on 2M mobiles?
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by KV4BL on April 21, 2003
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Excellent post, Meade! I, too, noticed this omission when purchasing a 2100H to run mobile after having the excellent 2000H on base. Other things Icom left out on the 2100 included DTMF squelch capability and rapid DTMF encode capability. Admittedly, I was glad they figured it out and included CTCSS decode as standard but was disheartened with their decision to eliminate the DTMF encode/decode ability, as a close friend and myself had fun with this on a simplex frequency with terrible local intermod problems. I noticed at least one post taking you to task for not knowing about a multitude of radios with air band receive but I think they missed your point that "2-meter" radios with air band rx ARE getting scarce, as most of those listed by them were dual-band radios. I miss this feature as it was a way to switch over and monitor the local airport if one observed a craft making erratic movements to see if their was a problem or someone was just playing or learning to fly. Occasionally, it would come to my attention that a craft was going to attempt to land and was experiencing difficulty with landing gear or whatever and this, again, was a plus for air rx as well as when dropping off friends or relatives at the airport and listening to their flight on the radio till they were out of range, and knowing that they were OK for at least that far. I wasn't enough of an air buff to go out and "buy a scanner" for that purpose and even if one were, there isn't that much room in many of today's compact and even medium sized cars for the extra radios. I am an Icom man, with the vast majority of mobile radios I own being Icoms, but they have been in the habit of dropping the ball on several things as of late, such as replacing the excellent 2800H with the abomination known as the 2720H (200 memories and NO alpha tags). There are times that the air band is a nice novelty and while I can live without it, I know of at least one potential ham who may get his license because he is an air buff and was intrigued with the air rx on my 2m and dual band mobiles. Seems as they pick up on one thing (like needing fans on radios so they don't cook off at high power with keydowns for more than 5 seconds out of every 10 minutes), they lose some other good feature, like air band rx or rapid DTMF xmit which sounds so much better when acessing speed dial on the local autopatch than the slow lumbering dial of many newer radios. 73, Ray KV4BL
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by WA2JJH on April 21, 2003
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Aircraft RX on my FT-100D is a waste. I am maybe 10 miles LOS of 3 major airports. AIR RX S1-S3. IMOD,
FM broadast image,and TV transmitter sync buzz all S9!
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No more AM air RX on 2M mobiles?
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by N6TR on April 21, 2003
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Another useful use for the AM receive mode is for chasing down QRN. I use my HT on the AM band all of the time to find electric fence noise and occasionally for power line noise.
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RE: No more AM air RX on 2M mobiles?
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by KG4UOQ on April 21, 2003
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I'll put in a plug for the IC-706 family... handles air band quite nicely. Quite a bit more expensive than your normal mobile rig. And yes, it will do 2M AM, if you just want to do something strange to say you have, and can find someone to be on the other end. [big grin]
I think the air band has stuck with AM for two reasons:
1) It started off as AM long before SSB was available, and when you're talking tube rigs, the AM gear weighs less. And they're simpler. And aerospace engineers are the most paranoid, conservative people you'll ever meet.
2) From a human factors standpoint, you want something that gives nice, channelized operation and doesn't require a lot of fiddly precision tuning, potentially chasing the dial trying to follow someone with a fifties-era tube radio that's changing temperature, altitude, and orientation. There's plenty going on in the cockpit without having to fiddle with the radio. That leaves you AM and FM to choose from (of the modes available in the late fourties and early fifties that didn't require precision tuning) and AM rigs were lighter, simpler, and used less bandwidth.
In the commercial service in the 220-221 band (I know this is a sore point) we're going to see folks go from 15 kHz FM channels to 9 kHz AM channels in the next few years (can't remember the date). The thinking is that AM is narrower, so you can carry more channels, and modern DSP is closing the gap on QRM. Good news is that this could create a small wave of surplus 1.25M HTs.
Seems like brave people could put in a switch to select between the discriminator and a diode detector. It would look a *lot* like a 9600 baud mod.
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by AA5TB on April 21, 2003
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Maybe it is because the future is here already and aircraft band AM will soon be obsolete (or is it obsoleted?)...
http://www1.faa.gov/nexcom/index.htm
Steve - AA5TB
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RE: No more AM air RX on 2M mobiles?
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by K9PO on April 21, 2003
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>No more AM air RX on 2M mobiles? Reply
>by AA5TB on April 21, 2003 Mail this to a friend!
>Maybe it is because the future is here already and >aircraft band AM will soon be obsolete (or is it >obsoleted?)...
>
>http://www1.faa.gov/nexcom/index.htm
>
>Steve - AA5TB
AM for planes is sooo entrenched into the aircraft systems it will be years before it is completly replaced. Shoot we still have NDB (non directional beacon) approaches for instrument flying. These date back to the 1930's and we still cannot get rid of them even though GPS is a much better way to go. But since GPS is not in every plane we use the old stuff too.
BTW the average AM radio for a panel in a plane (yep the small Cessna's) runs in the $1000 range, even more if want features that make it really nice like beacon recevie, VOR nav receive, ILS, etc. not cheap. I would definetly respond to any NPR from the FAA obsoleting these radios as a stupid thing to do. AM works, has for years will for years more.
Scott
Scott
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by W0LPQ on April 21, 2003
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The Kenwood TM-241A had airband receive, it stunk. Had to be on the airport to hear anything. However, the TMG-707A is one heck of an airband receiver, as well as Public Service and 2/440 bands.
The G-707A sensitivity is gobs ahead of the older TM241. Audio quality is likewise ahead of the 241.
Agree with Steve about aircraft AM going away...that is eventually. That is the grandiose plan anyway. New radios are out that are more digital than they ever used to be. And...not just referring to the tuning modes between the radio and control head. But it will be many years before the old reliable AM goes away. Also agree that scanners leave a lot to be desired...!
73
Bill, W0LPQ
Collins Avionics Field Service, Retired
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by KB2SSA on April 21, 2003
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Toy feature to most people. By eliminating the 108-136 band they can increase the recv sensitivity and make the radio less prone to intermod. It ensentially is now filtered down to its purpose, 2 way communication. If you want a scanner get a scanner.
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RE: No more AM air RX on 2M mobiles?
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by RobertKoernerExAE7G on April 21, 2003
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I don't even want general coverage, let a lone FM in a HF rig.
Ideal for me is a receiver designed for 160-40 and a receiver designed for 30-10 coupled with a transmitter.
Better receivers for ham bands would be nice, not compromised receivers for the ham bands so that they can cover everything.
Bob
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by N6AJR on April 21, 2003
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I just checked and my yaesu VX5R, my yaesu FT 847, both go there and my 707 by kenwood goes to 118 also I think my kenwood 231 goes ther too. these are all pretty new and no problem... I really like the ft-847 160 to 10 meters, 6 meters 2 meters and 440 mhz am,fm, cw and ssb on all bands 100 watts on all except 2m and 44 which is 50 watts and true dual band operation so you can hear your self on satalites. It also has the best reciever of any of my rigs.. I like it tom N6AJR
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RE: No more AM air RX on 2M mobiles?
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by KD1S on April 22, 2003
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I'm in the market for a new radio and happened upon a description of the Icom IC-706MKIIG, from Icom's web site for the 706 <http://www.icomamerica.com/amateur/hf/ic706mkiigmain.html>
I see it has continuous recieve from 0.03 - 200 MHz Broadband All Mode Receive - that would include aircraft AM and the price is right on this baby. Granted, it doesn't have direct frequency entry but I'm not all that concerned about that if it's got a way to selectively change the MHz side or a nice fast jog dial.
I'll be putting my Yaesu FT-5100 up on ebay soon - can't wait to get back on HF!
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No more AM air RX on 2M mobiles?
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by WA2JJH on April 22, 2003
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Visa-vi, Mobile DC-TO daylight rigs go. It seems that the 706 out performs in out of band VHF vs the FT-100D.
As for UHF out of band the FT-100D is the clear winner.
I can deal with poor air-AM in exchange for good RX up to 900MHZ. Like to listen to local police in NYC
470-485Mhz.
The swiss army knife approach to a radio is space saving, and convenient. My prized TS-850SAT is gathering dust, even though its RX on HF runs circles around both mobile radio's. Not even the DSP brings the FT-100D close.
However it is nice to have a swiss army knife radio. Less to carry around. Go from 20M to 440 at a push of a button.
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No more AM air RX on 2M mobiles?
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by K1MKF on April 22, 2003
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The reason is simple - those inexpensive VHF FM only Ham transceivers are actually public service radios. Since the Police Deptartment or the local Heating Oil delivery service doesn't care about Air band rx it was left out. Many, many more of these radios are sold to the public sector and Hams are just riding the along for a cheap radio. The dual band radios are made for Hams and as such have all the bells and whistles. But, they also cost a lot more. A simple trade off.
Mark
k1mkf
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RE: No more AM air RX on 2M mobiles?
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by WA9SVD on April 22, 2003
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Erik (KG4UOG):
I agree, that Aircraft used AM because SSB hadn't been developed (certainly not as a commercial system) at the time aircraft radio was developed, and AM (or FM) allowed a "channelized" system without the necessity for fine tuning.
But I diasgree with the statement that AM radios are(were) "simpler, lighter" designs. FM is by far a simpler design, requiring a simple low level audio stage to modulate the oscillator. Particularly when first developed, the original AM radios required an audio system that had to produce audio at 50% of the RF input power, (50 Watts RF input would require 25 Watts audio, which would add something the size of a tube-type mono Hi-Fi amp!)and used a modulation transformer. Thus, the weight and size of an AM transmitter (for a given power output level) would be larger and heavier.
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No more AM air RX on 2M mobiles?
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by AG4HY on April 22, 2003
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the air band is also on vhf, don't remember exactly what the frequencies are, but a scanner frequency book will show it. also a lot of other interesting details, like who is licensed where and what frequencies, albeit some are dead as a doornail but they still have the license for it. nearly all of the cell frequencies now are digital so a scanner is basicly useless on them, not that i care enough to squak about it.
a scanner isn't all that costly, new and some used ones can be had reasonably as a lot of people got them for the cell freq's, so check around, you possibly can find one in your area, reasonable.
Yahoo auctions had some, that were being sold,and the bids weren't all that much. which ever way you go, hope you a lot of luck and enjoyment.
73
ag4hy
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No more AM air RX on 2M mobiles?
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by W4KSR on April 22, 2003
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I think I've used AM recieve in my radios over the years for about 10 minutes at most. I'm more interested in the VHF Public Service. Besides that, I saw scanners at a local hamfest in the range of $10-40 that would do aircraft.
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RE: No more AM air RX on 2M mobiles?
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by N0XAS on April 22, 2003
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My Kenwood TM-G707A will receive AM air band. In fact, I *think* it will receive AM on any band you want. I'm out of town and can't check it at the moment, but the op manual is available on line. No AM transmit, though, not that I'd ever need it anyway.
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RE: No more AM air RX on 2M mobiles?
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by N8FVJ on April 22, 2003
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Never used AM capacity on radios I owned with this feature.
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No more AM air RX on 2M mobiles?
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by W0LPQ on April 22, 2003
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Aircraft Communications band is 118.00 to 136.975 in the US. The Navigation (VOR/LOC) runs 108.00 to 117.9.
US has 25khz channel spacing for comms, while the European channels are 8.33khz. Smaller area, lots of airplanes and they ran out of channels.
73
Bill, W0LPQ
Collins Avionics Field Service, Retired
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No more AM air RX on 2M mobiles?
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by WB9YCJ on April 23, 2003
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I was told the reason AM has always reigned over nbfm (in aviation) is because of the safety benefit.
That is, there is no cancellation effect with AM.
Particularly, if a Pilot's (or tower's) sudden emergency or distress transmission is emitted "in competition" with another carrier, even though the Pilot's distress message signal is weaker, it can "often" be heard "under" the stronger signal (think back to your CB days).
Had FM been used in this situation, the "distress" message would not have been heard and actually been "cancelled" out. Anyway, this makes sense.
Ken
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No more AM air RX on 2M mobiles?
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by KD7EZE on April 23, 2003
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I don't understand your inability to pick up AM-air on a 2 meter rig. Of the 12 or so mobiles and HT's that I own, all of them will do it. And, no names mentioned, I have a dual band HT that even transmits on the air band, in AM mode. It has never been opened up, and has only had a keypad entered mod. Those of you that have one know which one I'm talking about. Two of my rigs are only a couple of weeks old, and they receive AM-air with no mods, and no problems. Some of the older ones have been modded for this feature. If you're really into air band, buy a scanner, or better yet, buy an air band HT.
'73
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No more AM air RX on 2M mobiles?
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by WA2JJH on April 23, 2003
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Yes an air band H-T will a great RX. One caution.
In NYC some guy got a major FEDERAL hassle over having one. Yes it was a couple of days after 9/11.
Still MOS will queston you. Why do you have a Air H-T
and no Cessna!
I am ignorant in this area. But common sense would dictate they would not sell an aviation H-T to the average JOE. Please feel free to enlighten me on this.
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RE: No more AM air RX on 2M mobiles?
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by K8MZO on April 23, 2003
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**I like having AM to listen to aircraft freqs. Why the airline industry stuck with AM is beyond me!**
Two words: capture effect. I'm amazed that no one really mentioned it so far...I think it's even on the tech test...
Also, to the original poster: the Kenwood TM-261 is a great single band radio IMHO, but the AM reception stinks. My Icom 207H does a pretty good job on AM however.
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RE: No more AM air RX on 2M mobiles?
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by W5HTW on April 23, 2003
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auote:
I was told the reason AM has always reigned over nbfm (in aviation) is because of the safety benefit. That is, there is no cancellation effect with AM. Particularly, if a Pilot's (or tower's) sudden emergency or distress transmission is emitted "in competition" with another carrier, even though the Pilot's distress message signal is weaker, it can "often" be heard "under" the stronger signal (think back to your CB days). Had FM been used in this situation, the "distress" message would not have been heard and actually been "cancelled" out. Anyway, this makes sense.
Ken
That's part of it. Long haul aircraft have switched to SSB years ago as their primary over-the-water communications mode, with distinct advantages.
Also, when aircraft began switching from CW to AM, FM was relatively new, and almost entirely wideband. It was "untested technology" and the natural progression was to AM. That snowballed.
But the problem with converting aircraft to SSB, or even to digital is this - have you any idea how many aircraft there are in the world? It boggles the boggles.
It would take trillions of dollars and gobs of years to convert them to digital, FM, cell phone or anything else. And most of us are not in the mood to pay trillions of bucks in taxes world wide to fix something that actually works as it is. It may be that aircraft, commecial and military at least, produced in the near future will have radios that can operate other modes but they are going to have to retain that AM capability for many, many years to come. General aviation aircraft would, if the law changed today, be at least 20 years converting over and by then who knows where technology would be?
It's a problem that really doesn't need fixing. Narrow channel spacing has helped. We went from 360 channel to 720 channel and good filtering and all sorts of improvements over the years, but AM is still the way to go.
Now, to the topic at hand! My IC-2000H is still my favorite VHF radio, despite getting old (so am I!) It works wonderfully on AM air. My IC706 does, too, and so does my VX5R. And I do like to listen, so I have local municipal airport (uncontrolled) plugged into all of them, plus some ARTC channels. If, though, my ham radios did not cover air, I would buy a scanner. My old Radio Shack scanner from 1987 works great on air band. If ham radios drop the air band, no big deal for me. A scanner the size of a miniature cell phone does the job quite well.
73
Ed
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No more AM air RX on 2M mobiles?
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by K4CMD on April 24, 2003
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I can't believe many of you. I posted this article. If you read it while paying attention, you'll notice I was talking about TWO-METER mobiles -- NOT dual-banders, NOT HF rigs, NOT HTs. I was looking for a mobile, single-band 2-meter rig to put in the shack. 440 is not used in my city, and I already have an HF-to-6 meter base radio. I needed a 2M-only rig for the shack. To those of you recommending $400 dual banders and $1200 mobile HF rigs, thanks but that's not what I'm talking about. To those of you who say "I have lots of 2 meter rigs and they all do aircraft" -- go out and try finding one that's being sold NEW today. Your only choices are an Alinco (I'm not an Alinco fan and apparently a lot of reviewers here at eham aren't either) and a Kenwood 261A that's been out for at least half a decade and is just a re-faced 231A from more than 12 years ago (I know; I owned one). Icom and Yaesu do NOT offer a 2M mobile with aircraft receive anymore. I know; I went out to buy one guys!!! Geesh, I even received an e-mail from a ham who was trying to be helpful by recommending a 2M mobile that didn't receive the aircraft band!?!?
I was trying to make a point from the point of view that I've been in ham radio for more than 20 years and this feature was useful and interesting to ME. Obviously your mileage is going to vary. We all don't have the same interests. But at least, puh-leeze, read the article before you respond to it.
K4CMD
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RE: No more AM air RX on 2M mobiles?
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by K7IHC on April 26, 2003
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Ok. Elaborating on my original posting: *I* see no large market for a 2m MOBILE with AM aircraft RX. That's probably why the manufacturers are phasing them out. Most manufacturers probably sell more dual-band mobiles than 2m mobiles, too. I do see a purpose for a 2m (or dual-band) portable with AM air RX (travelling by commercial airline). A dual-band mobile, like a Kenwood TM-G707A, can be found new for $265. It has very good reception on the AM aircraft band. No 70cm band usage in your area? Are you in an extremely rural area? In my area there must be at least 60+ open 70 cm repeaters within 50 miles.
For use as a base (shack) radio for AM air RX, I still think a mobile/base scanner would do well. And you would be able to use the 2m radio while monitoring aircraft.
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No more AM air RX on 2M mobiles?
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by WA2JJH on April 26, 2003
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K4CMD. Gee I guess we should all be sorry we did not answer your exact question for you. We are not paid well.
Sure we went out of the scope. However there is an old zen saying ask one question, and 3 more questions will pop up.
We are hams from all around the USA. Many times a thread will go off tangent. So what! Are we here just to answer your question. We all have questions.
I was glad that professional aviation people checked in to answer my derivitive question, why has not aviation switched over to FM. I got answers I wanted to know.
Abeit a snooty remark was made, like that is a TECH CLASS ANSWER YOU SHOULD KNOW!
I know why 13ghz Gunn Diode injection locked amplifier's can use the same waveguide for input and output! That is one the OLD 1st class Commercial radio TELPHONE testI took! I have been an EXTRA for 20 years.
So I get lambasted by some one about capture effect on the new watered down TECH test.
Just because you start a thread, does not mean we will be here 24/7 to answer your exact question.
I now know I made the right decision not to be recertified for CPR and FIRST aid!
A thread is not your customer service line for your computer!
So we went off tangent, so what. Many people gave you
an answer with good intentions. We did not have to do that!
Much info was unturned on why commercisl avaition uses AM. a QUESTION I WANTED TO KNOW!
Sometimes a thread will take on a life of it's own.
As a result other questions get answered, besides yours! So a few fellow hams had other idea's for you.
They did it out of the spirit of ham radio
EHAM has a great talent pool. WE answer questions PRO BONO PRO RHEA NATA SANS QUID BON PRO!
I will not apologise for that. Next time why dont you call the radio manufacturers instead and ask them!
I now know I made the right decision not to be recertified for CPR and FIRST aid!
Have a lousy day!
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No more AM air RX on 2M mobiles?
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by N8XLT on April 26, 2003
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I AGREE! As a ham who is also a pilot, this is an invaluable tool and I'm very sorry to see it go. With the "cockpits" of most modern cars like my '02 Impala being so cramped, it's nice not to have to have another radio in the car. I use a dual bander that can also receive the air band. It is a Godsend.
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No more AM air RX on 2M mobiles?
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by K2VI on April 26, 2003
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If your looking for a brick wall recieve(which i am)then the aircraft recieve is a non issue.I have a few scanners to do that job.remember the radio shack htx 202(was made by maxon)this radio had recieve capabilities of 144-148 mhz.it had no intermod what so ever.this radio had a super reviever.great dynamic range.why?because it had a narrow banwidth only recieving 144-148.so if you want a great radio get one that doesnt recieve everywhere.if your looking for a 2 meter ht why would anyone want it to recieve aircraft?
get a scanner!
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No more AM air RX on 2M mobiles?
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by KG4BON on April 27, 2003
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I have enjoyed reading this post. I have run into the same reasoning while shopping for a new radio. I asked the same question to my dear friend Jose at my local family ham radio store Eli's. I remember hearing him bring up many of the exsamples mentioned.
Also:
I belive cutting costs to manufacture the radios is a large part of it. We Ham's are very difficult to please. We want ALL the latest technology in our equipment, but we do not make a living from our radios so we can not afford to invest too much cash.
I personaly complement all the radio manufactures for there continued investment in Ham radio equipment. As you can see from the cost of a simple aircraft am radio ($1000.00+) and other more profitable ventures that we should be very happy with the choices we have.
I Just went to the Galeston Air Show this weekend and me and a lot of my friends were very happy to have the air band receive.
I have had radios with and with out air band and yes there is a slight differance in intermod rejection but I have found if your in a bad rf area, some of newer standard features helps much more than a few dbi's of rejection.
There are a few dual band radios with air band receive that are only a few dollars more than some single band radios.
As a Ham radio operator I understand I should be ready to help with passing emergency trafic when called. Because the people I may have to assist may not have all the communication means I have, I will be ready to listen on there terms (freq).
Thanks for all the great years of putting up with me and my silly questions Jose!!!
KG4BON 73's
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RE: No more AM air RX on 2M mobiles?
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by K4CMD on April 28, 2003
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WA2JJH ...
It's folks like you who provide the "cons" to the pros and cons of ham radio. Thanks so much for keeping the scale balanced.
Meade
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RE: No more AM air RX on 2M mobiles?
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by W7UIV on April 28, 2003
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I wonder how many others got a chuckle out of the post where the fellow made reference to the time back when ham equipment only covered the ham bands.
This lack of general coverage was one of the biggest gripes against the "new" generation of equipment that started showing up in the latter 50s/early 60s.
Another grip was that so much of it was only good for one mode (SSB). Now that I think of it, this was probably a scheme to get rid of the CW requirement on tests. (hi)
With mainly the exception of Drake, the new equipment field was kind of dull for nearly twenty years until we we started getting it all back in the latter 70s/early 80s. (I'm speaking of the general run of affordable ham equipment, not Signal One) And I think we've gotten a whole lot more along with it.
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No more AM air RX on 2M mobiles?
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by KK5VN on April 29, 2003
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I have seen plenty of Hams that are pilots (myself included). The great thing is, Vertex Standard (Yeasu) has come up with a radio that will do the 2 meter band, broadcast FM, and the aircraft band. It is the Spirit VXA-700. Instead of me re-typing all the info off the website, I will just copy and paste.
############################################
AM Airband NAV-COM 5 Watts TX Power Output w/VOR/CDI Display
VHF FM TX 144-148 MHZ (Amateur Radio Band) 5 Watts*
NOAA Weather Receive w/Severe Weather Alert
FM Broadcast Receive 88-108MHZ
A first in aviation communications! Vertex Standard has combined over 40 years experience in amateur radio communications and their expertise in aviation communications to make the world's first Air Band, VOR Navigation and Amateur Radio 2 meter and held transceiver!
Features:
5 Watts TX Output Power
FM Radio Broadcast Band Receive (88-108 MHz)
190 Memory Channels with alpha Numeric display
Submersible (JIS 7) 3 feet for 30 minutes
Rugged Magnesium Die-Cast Construction Offers superior shielding from RF noise plus unparalleled ruggedness
Includes Rechargeable 1300 MAH Li-Ion Battery - Twice the battery life of any airband transceiver available today
Multi-color Strobe LED
PC Programmable VOR Navigation Display
High Resolution Dot Matrix Display (backlit)
Back-Lit Keypad and Display with Dimmer
One Touch Emergency Frequency (121.5 MHz) Access
RX Battery Saver
CTCSS and DCS Operation (FM 144 MHZ Band)
NOAA Weather Channel Receive (USA Version Only)
NOAA Weather Alert (USA Version Only)
Valid Amateur Radio License Required for Operation on Amateur Radio Frequencies
Included:
Li-Ion Battery
Charger
Headset Adapter
Antenna
Belt Clip
I found this radio on pilotmall.com . Hope this helps.
Patrick
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No more AM air RX on 2M mobiles?
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by K9MRK on May 2, 2003
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I'm also a pilot and like to keep ATIS frequencies
programed in my radios. Nice to be able to check
weather and operations before getting to the
airport. It's a nice feature but I could live
without it.
I seriously doubt the FAA will anytime soon
phase out AM. With usually 2 COM radios per
small plane, often combined with the NAV
radios we're talking very serious money.
The FM capture effect thing is a big deal.
Two planes "double" transmissions on AM and
ATC knows they need to sort something out.
They'd never know it on FM. Keeps people
from accepting instructions meant for someone
else and ever having to assume you were heard.
It's a great "feature".
- Mark K9MRK
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RE: No more AM air RX on 2M mobiles?
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by KC8WCW on May 12, 2003
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KK5VN: Why don't you just run an ad for Vertex and be done with it? You sound like a sales rep.
KC8WCW
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No more AM air RX on 2M mobiles?
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by K3YD on October 19, 2004
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Have you seen the new ICOM IC-2200? It appears that ICOM heard you--and built a new radio just for you, and those of us who want similar AM/Aircraft Band RX capabilities.
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