Listening to HD Radio on a plane

[nd2023]

I listened to my Insignia portable HD radio on a flight from Philly to Tampa.
On the ground in Philly, I could pick up all the Philly HD stations. They were all gone when the plane was over 10,000 feet, but analog reception was fine. I noticed intermittent HD reception on some of the Washington DC stations. Then, Q94.5 out of Richmond was in solid HD for about a 100 mile radius of Richmond. Even when the analog 94.5 had another station, WRVQ was blasting in HD. Then, no more HD until Jacksonville, where 95.1 WAPE was the only HD station blasting in. As the plane descended, I could pick up the Orlando HDs and Tampa HDs.
The selectivity of this radio was impressive, with no adjacent channel bleed. I could hear other stations on 94.3 and 94.7 while flying near Richmond. It also picked up RDS from any station transmitting RDS. The station that stayed the longest was Hot 100.5 out of Norfolk, VA. I could get it all the way from southern NJ to the NC/SC border. Even on land, Hot 100.5 has a big signal.

I'm guessing that the performance in an airplane will be about the same as its performance during an e-skip opening.

I wonder why it would only be able to successfully decode HD from a handful of stations. The HD indicator flashed for many other stations, but it didn't decode most of those. But for the 2 that it did decode, those HD signals were solid for over 100 miles.

 

[Play Freebird]

Interesting report, and it makes sense. Most of the Philadelphia stations have first-adjacent neighbors in the NY or Baltimore/Washington areas which interfered with the digital sidebands once you reached the 10,000 ft altitude. And depending on the flight path, you may have been "too close" to some of the other stations to receive a good signal. Antennas designed to suppress downward radiation (to reduce the RF hazard at ground level) also reduce the signal going up.

You might want to look at the actual flight track on a map and see how far out you were from WRVQ. The website www.flightaware.com retains this information for several days.

 

[audioguy]

So Nick--

Did you happen to mention to the pilot of this aircraft that you were listening to an FM radio on board, with the LO signal right in the middle of the air communications band?

Glad I wasn't on that flight!

 

[Play Freebird]

The LO leakage problem from portables isn't as severe as it once was, so some airlines have decided to allow use of FM radios after reaching cruising altitude. However, when I take my 1980-vintage FM Walkman on commercial flights, I avoid tuning above 97 Mhz just to be safe.

A couple of years ago, I flew New Delhi to London and caught some interesting FM signals over Azerbaijan, Georgia, Armenia, Moldova, etc. One of the morning shows was having "too much fun" with their new Harmonizer; it reminded me of an early '80s Morning Zoo.

 

[audioguy]

The LO leakage problem from portables isn't as severe as it once was, so some airlines have decided to allow use of FM radios after reaching cruising altitude. However, when I take my 1980-vintage FM Walkman on commercial flights, I avoid tuning above 97 Mhz just to be safe.

Which airline would that be? I have flown over 100,000 miles during the past two years on American, United, British Airways, and Lufthansa and have never been told that listening to the radio on board is permissible.

 

[Play Freebird]

The LO leakage problem from portables isn't as severe as it once was, so some airlines have decided to allow use of FM radios after reaching cruising altitude. However, when I take my 1980-vintage FM Walkman on commercial flights, I avoid tuning above 97 Mhz just to be safe.

Which airline would that be? I have flown over 100,000 miles during the past two years on American, United, British Airways, and Lufthansa and have never been told that listening to the radio on board is permissible.

British Airways. I always check the airline's written policy for use of electronic devices (which can be found in the back of the "in-flight magazine") and if it prohibits use of radio receivers, I refrain from listening to FM or using a GPS. However, in this case, BA's policy permitted both. And as I mentioned before, I made sure to keep the LO below 108 as my Walkman is an older non-synthesized model without the best shielding.

Needless to say, the use of transmitters is almost always out of the question, but an increasing number of airlines now allow receivers once the aircraft reaches cruising altitude. For example, see:

http://gpsinformation.net/airgps/airgps.htm

 

[audioguy]

Thanks for providing that information. I will check the inflight magazine next time I am on a BA flight.

However, a cautionary note: the link you provided pertains specifically to GPS receivers if I understood it correctly. Those operate in an entirely different band. I don't necessarily believe that approval to use a GPS receiver implies approval to use an FM radio on board.

 

[Play Freebird]

Thanks for providing that information. I will check the inflight magazine next time I am on a BA flight.

However, a cautionary note: the link you provided pertains specifically to GPS receivers if I understood it correctly. Those operate in an entirely different band. I don't necessarily believe that approval to use a GPS receiver implies approval to use an FM radio on board.

If the airline policy specifically approves use of "radio receivers", then I take that as "no problem" for FM. Sometimes they make a distinction for GPS, but not always.

Anyone here know if the FM receiver chip in the new iPod Nano operates whenever it's powered up, or only when selected in the menu? As FM capability makes its way into more and more PDAs, music players and other handheld devices (which are normally approved by nearly all airlines) the definition of a "receiver" becomes blurred.

To move this thread back on topic, any thoughts about the proposed increase in HD digital power within the portion of the aeronautical band between 108.0 and 108.1 MHz? It may become legal for a Class C FM station on 107.9 to radiate at least 2 kW and possibly 5 kW in this range, in addition to 100 kW in the analog channel within the actual broadcast band. If an aircraft is flying near one of these stations and its VOR receiver is susceptible to third-order intermod, some interference products could fall directly atop a 108.2 MHz VOR signal.

 

[SUPERCASTER]

IBOC was to be In Band On Channel. Unfortunately the FCC approved HD radio system is not.
Misrepresented?
Quite possibly.
But the lobbyists won.
FMeXtra is IBOC.