Heard my first AM-HD hash today

[hitNrun]

I knew, that HD-AM caused adjacent-channel interference, but I wanted to find out for myself. With my digitally-tuned car and hand-held radios, I have not noticed the digital saddle-bags on AM (of course), but today, I tried one of my analog-tuned radios and found this constant rushing sound of a waterfall (almost, like the sound of waves washing ashore, but amplified 100 times), JUST above and below the main analog channels on three AM stations. So, I went to iBiquity's site, and sure enough, they listed the three stations broadcasting in AM-HD (the only ones, in my area):

http://www.ibiquity.com/hd_radio/hdradio_find_a_station

There is absolutely no doubt, this was not just regular interference from electrical devices (sounds differently - too consistent), because I tried the radio downstairs, upstairs, and outside, well-away from the house, with the same results. This technology, if implemented widely, will doom the AM band. For what it is worth, I did email the three AM stations to complain.

 

[Mike Walker]

Now I love corned-beef hash, but not too sure about "AM Hash". Seriously, would you mind making a recording of what you heard, and posting it? If you don't have a website to post it to, e-mail it to me at [email protected] and I'll post it on my website so others can hear what you're talking about.

 

[rbrucecarter5]

I wish I had made recordings from a recent DXpedition to Galveston. I was able to hear HD hash from stations hundreds of miles away - stations whose analog component I couldn't hear.

I do have a recording of a local HD station that had shut down its analog modulation, but still was broadcasting (idle) sidebands. I tuned through +/- 40 kHz while recording, it is DRAMATIC. I also was able to record that peculiar "warbling" sound that you get when you are perfectly on frequency. It has to be assymmetry between the sidebands showing up as amplitude modulation. I'll see if I can digitize it as a .WAV. MP3 would not do justice to the problem.

 

[hitNrun]

Now I love corned-beef hash, but not too sure about "AM Hash". Seriously, would you mind making a recording of what you heard, and posting it? If you don't have a website to post it to, e-mail it to me at [email protected] and I'll post it on my website so others can hear what you're talking about.

Unfortunately, I don't have the hardware, but I can tell you, as of 7:30PM, the hash is gone from all three stations - it sounded exactly, like standing next to a large waterfall.

 

[Mike Walker]

rbruce, I find that Windows Media at 128kbps or so is good enough to show up differences in audio quality. Sounds a lot better than low bitrate mp3, and is much smaller than .wav. Just a thought.