Thunderstorms wreak havoc with MY reception!

[Mike Walker]

In the interest of full disclosure, and in answer to the charge that I simply parrot the "Alliance" line, I was listening to "All Things Considered" this afternoon on WFHE in Hickory, NC...about 40 miles away. There were thunderstorms to the south and west of me...I know because I heard a forecast. I noticed that the audio level kept getting MUCH louder, then quieter again. Well I had noticed that the digital level on WFHE was a good deal lower than analog, so I assumed they were making adjustments. Then I looked at the display. Holy Crap Batman! HD was switching in and out at about every few seconds...apparently corresponding to lightning crashes too far away for me to see/hear. This is my first thunderstorm season with HD...I got my radio on "Black Friday". I'm learning what to expect!

 

[PocketRadio]

I just looked up WFHE on iBiquity's web site and noticed that WFHE is an FM station - I just assumed you were referring to an AM station, with the usual electrostatic interference problems ! Analog FM always seems pretty much immune to lightning, but to make the FM digital signals crash is major - I wonder, why this hasn't been mentioned before ?

 

[R.F. Burns]

In the interest of full disclosure, and in answer to the charge that I simply parrot the "Alliance" line, I was listening to "All Things Considered" this afternoon on WFHE in Hickory, NC...about 40 miles away. There were thunderstorms to the south and west of me...I know because I heard a forecast. I noticed that the audio level kept getting MUCH louder, then quieter again. Well I had noticed that the digital level on WFHE was a good deal lower than analog, so I assumed they were making adjustments. Then I looked at the display. Holy Crap Batman! HD was switching in and out at about every few seconds...apparently corresponding to lightning crashes too far away for me to see/hear. This is my first thunderstorm season with HD...I got my radio on "Black Friday". I'm learning what to expect!

I'll have to keep an eye on my radios this year. I never had any issue with IBOC on FM in the past. Now that the seaosn is coming upon us I'll also check the AM IBOCs. I can record them. It would make an interesting demo.

 

[clouseau]

I just looked up WFHE on iBiquity's web site and noticed that WFHE is an FM station - I just assumed you were referring to an AM station, with the usual electrostatic interference problems ! Analog FM always seems pretty much immune to lightning, but to make the FM digital signals crash is major - I wonder, why this hasn't been mentioned before ?

It's a shame you didn't look it up on the FCC Database. It's a Directional 4 KW station. At a claimed distance of 40 miles Using their transmittingin that would give a signal strength of 41.876 dBu as per the FCC Curves Program. City Contour is 70 dBu Protected is 60 dBu. If it was another 2 miles away, it would be legal to have protected contour at his hose from ANOTHER station. In other words it's massively DX. Perhaps some of the folks here would like to go around bragging that HD doesn't work on FM's when there's a thunderstorm and the signal strength is under 42 dBu.

As a sidelight, assuming WFHE was the only station in the world and everything else was open, It would be within the FCC rules to build a maximum power translator at 250 feet high at Mike's house on the same frequency as WFHE. (Interference contour of 40 dBu goes 21.3 miles. Protected 60 dBu Contour of WFHE is 17.8 miles. Total seperation needed 39.1 Miles) Neither would interfere with each other.

Sometimes a little information is a dangerous thing. The picture changes DRAMATICALLY when you get the whole picture.

Clouseau

 

[Mike Walker]

Oh yeah, it's a dx target for sure. Often I can't get the analog fm signal on my car radio, but I can consistently get their HD (one percent would be FORTY WATTS!). So I'm not complaining. I just thought it was interesting to show that thunderstorms can affect FM HD reception. Of course, they can affect analog reception too. Noise is much less than AM (of course), but listening in stereo you can hear lightning crashes in a severe thunderstorm. Of course with most storms it goes unnoticed.

Again, there were severe thunderstorm warnings (meaning there were actual severe thunderstorms) in exactly the direction that WFHE was coming from (although more distant than WFHE).

By the way, WFHE, 90.3, acts as a kind of high power translator for WFAE (90.7) in Charlotte, duplicating their programming 100 percent. I thought it was interesting that they converted the 90.3 signal to HD, especially considering the low power...and see it as an example of what HD would be like on smaller, community stations...the ones Clear Channel and CBS aren't interested in

We're all in a learning curve with HD. As I said, I've never had a chance to listen during a thunderstorm, and had no idea what to expect. We'll learn!

 

[Mike Walker]

Thanks for the specifics, Clouseau. As I've said before, except for the 100 kilowatter here in Wilkes County (WKBC-FM), ALL FM is a "dx target" at my location That fact that I even get HD with an indoor antenna still blows my mind.

 

[awj223]

Oh yeah, it's a dx target for sure. Often I can't get the analog fm signal on my car radio, but I can consistently get their HD (one percent would be FORTY WATTS!). So I'm not complaining. I just thought it was interesting to show that thunderstorms can affect FM HD reception. Of course, they can affect analog reception too. Noise is much less than AM (of course), but listening in stereo you can hear lightning crashes in a severe thunderstorm. Of course with most storms it goes unnoticed.

Again, there were severe thunderstorm warnings (meaning there were actual severe thunderstorms) in exactly the direction that WFHE was coming from (although more distant than WFHE).

By the way, WFHE, 90.3, acts as a kind of high power translator for WFAE (90.7) in Charlotte, duplicating their programming 100 percent. I thought it was interesting that they converted the 90.3 signal to HD, especially considering the low power...and see it as an example of what HD would be like on smaller, community stations...the ones Clear Channel and CBS aren't interested in

We're all in a learning curve with HD. As I said, I've never had a chance to listen during a thunderstorm, and had no idea what to expect. We'll learn!

If digital is usable at lower power levels than analog, shouldn't we be decreasing the signal power that we define as the protected contour in preparation for an all digital band? Maybe 45-50 dBu for FM and 100 uV/m for AM.

 

[PocketRadio]

... in preparation for an all digital band?

When, is that ever going to happen ?

 

[awj223]

When, is that ever going to happen ?

From the point of view of the FCC, it is. If HD fails, then we'll just end up with better protection criteria than we do now! I've always felt that the protected contours didn't extend far enough. The FCC rules seem like they were designed to protect the area usable by crappy receivers with bad antennas. I think signals should be protected as far as they can be reliably received on high end receivers with high end omnidirectional antennas: 30-40 dBu for FM and 20-100 uV/m for AM.

The real problem is that the FCC protected contours and masks don't represent what signals can be received in the real world. HD was even allowed to exist in the first place because those policies were so lax. Because those policies were so lax, HD can (legally) step on what was a usable signal. Had proper protection criteria that reflected reality been established from day one, any system fitting within the emission masks would not step on any usable signals.

So, it's time to move out those protected contours so that IF a digital conversion happens, the cochannel interference limiting each station's coverage isn't any worse than it is now.

 

[Chuck]

The real problem is that the FCC protected contours and masks don't represent what signals can be received in the real world. HD was even allowed to exist in the first place because those policies were so lax. Because those policies were so lax, HD can (legally) step on what was a usable signal. Had proper protection criteria that reflected reality been established from day one, any system fitting within the emission masks would not step on any usable signals.

There is a huge difference between FCC protected contours and what the general public considers acceptable signal levels. Where I live, most everything is actually a DX catch. I know that's not the way it is in Boston or New York, but it is reality in a lot of the country. I guess that is why HD gives me an uneasy feeling. I think we are creating two classes of radio listeners, as well as two classes of stations. I'm not sure that is a good thing.

 

[SUPERCASTER]

I just looked up WFHE on iBiquity's web site and noticed that WFHE is an FM station - I just assumed you were referring to an AM station, with the usual electrostatic interference problems ! Analog FM always seems pretty much immune to lightning, but to make the FM digital signals crash is major - I wonder, why this hasn't been mentioned before ?

It has been posted here many, many, times.
HD radio, as now constituted, has very poor interference immunity on HD AM or FM, especially more then a few miles from the transmitter.
There, I said it again!

 

[clouseau]

It has been posted here many, many, times.
HD radio, as now constituted, has very poor interference immunity on HD AM or FM, especially more then a few miles from the transmitter.
There, I said it again!

You are correct, it has been posted here many times. Especially by you. No matter how many times you post your opinion as if it were a fact, measurable information demonstrates a different conclusion. Assuming all the facts are as stated in this post, the signal level at the receive site is 42 dBu. I would suggest that only NASA thinks 42dBu is poor interference immunity.

Again, I ask you. Please STOP posting your opinion as if it were a fact.

Thanks

Clouseau

 

[Mike Walker]

How about I post a fact as if it were a fact, Clouseau?

The fact, as has been pointed out earlier, is that a 40 watt digital signal at 40 miles is pretty impressive (a mile per watt). Hard to say it "doesn't work", or "won't work on low powered stations".

Another point, many of us who live in rural areas, every station we listen to is "beyond the protected contours".

 

[PhilJSmith67]

I have experienced no problems with HD FM reception due to lightning at approximately 40 miles from Chicago using an indoor antenna. Not a single dropout. HD AM is a completely different story.

 

[clouseau]

The fact, as has been pointed out earlier, is that a 40 watt digital signal at 40 miles is pretty impressive (a mile per watt). Hard to say it "doesn't work", or "won't work on low powered stations".

To me, a "40 watt" signal 40 miles miles away is pretty amazing.

Clouseau

 

[calstymes]

Philip J. Smith conjectured:

HD AM is a completely different story.

HD AM is an embarrassment!

Where ARE the engineers at AM stations that have IBOC on the air who actually like this technology and think it provides an improvement to reception in the AM commercial broadcast band? We are all patiently waiting to hear from them as to why we should run out and purchase a receiver that is capable of decoding AM HD.

 

[clouseau]

HD AM is an embarrassment!

Maybe to some.

Where ARE the engineers at AM stations that have IBOC on the air who actually like this technology and think it provides an improvement to reception in the AM commercial broadcast band? We are all patiently waiting to hear from them as to why we should run out and purchase a receiver that is capable of decoding AM HD.

I''ve seen and read WOR being pretty boastful about it. Don't recall the specifics, but there is a fairly good sized section on their website and has been in Radio World at least once in a big spread.

They don't seem too embarrased by it.

Clouseau

 

[radiopilot]

HD AM is an embarrassment!

Maybe to some.

Where ARE the engineers at AM stations that have IBOC on the air who actually like this technology and think it provides an improvement to reception in the AM commercial broadcast band? We are all patiently waiting to hear from them as to why we should run out and purchase a receiver that is capable of decoding AM HD.

I''ve seen and read WOR being pretty boastful about it. Don't recall the specifics, but there is a fairly good sized section on their website and has been in Radio World at least once in a big spread.

They don't seem too embarrased by it.

Clouseau

That's weird, I went through the whole website and not one single engineer posts any info about the HD transmissions... it's basically the same rhetoric coming from Ibiquity.. almost as if radio stations became zombies of the Ibiquity Corp.

http://wor710.com/pages/48772.php

Radiopilot

 

[R.F. Burns]

HD AM is an embarrassment!

Maybe to some.

Where ARE the engineers at AM stations that have IBOC on the air who actually like this technology and think it provides an improvement to reception in the AM commercial broadcast band? We are all patiently waiting to hear from them as to why we should run out and purchase a receiver that is capable of decoding AM HD.

I''ve seen and read WOR being pretty boastful about it. Don't recall the specifics, but there is a fairly good sized section on their website and has been in Radio World at least once in a big spread.

They don't seem too embarrased by it.

Clouseau

That's weird, I went through the whole website and not one single engineer posts any info about the HD transmissions... it's basically the same rhetoric coming from Ibiquity.. almost as if radio stations became zombies of the Ibiquity Corp.

http://wor710.com/pages/48772.php

Radiopilot

Let me suggest you contact Tom Ray at WOR. He's the head of engineering for Buckley Broadcasting and he'd be very happy to answer any question you might have. Tom is very well schooled in IBOC. He's been running it for years, both at his old site and at the new location as well. Tom is also the head of SBE chapter 15.

 

[clouseau]

HD AM is an embarrassment!

Maybe to some.

Where ARE the engineers at AM stations that have IBOC on the air who actually like this technology and think it provides an improvement to reception in the AM commercial broadcast band? We are all patiently waiting to hear from them as to why we should run out and purchase a receiver that is capable of decoding AM HD.

I''ve seen and read WOR being pretty boastful about it. Don't recall the specifics, but there is a fairly good sized section on their website and has been in Radio World at least once in a big spread.

They don't seem too embarrased by it.

Clouseau

That's weird, I went through the whole website and not one single engineer posts any info about the HD transmissions... it's basically the same rhetoric coming from Ibiquity.. almost as if radio stations became zombies of the Ibiquity Corp.

http://wor710.com/pages/48772.php

Radiopilot

My humblest apologies. I really thought there was a whole tour with pictures on there. In fact I still think there was. Clearly you are correct. It's not there.

I did find this "OLD" Radio World Link
http://www.rwonline.com/reference-room/iboc/wor_goes_hd.shtml

And this slightly newer one...
http://www.rwonline.com/reference-room/iboc/06_rw_hd_wor_1.shtml

And This
http://www.rwonline.com/reference-room/iboc/01_rw_wor_iboc_install_2.shtml

BTW at the bottom of this last link is the address for the WOR site. It apparently has been removed. again, my apologies. I quoted the idea from memory.

http://www.rwonline.com/reference-room/iboc/01_rw_hd_kenwood_2.shtml
Here's a review of an HD in car radio by a WOR engineer.

And a personal opinion
http://www.rwonline.com/reference-room/iboc/04_rwrf_may_5_part_1.shtml

There are a great deal of engineering real world observations available out there. These are only from Radio World. In the final link is a pretty good assessment of Buckley and their company. Not exactly Clear Channel.

Clouseau