The Lubbock Icestorm

[EggsOverEasy87]

It looks like the storm did its damage.

Here were the stations that were knocked off the air for some time but are now back up:

88.1 KTXT
90.5 KBAH
91.9 KPGA
94.1, 99.1, 107.3 KGCE
105.3 KJDL

...Did I miss anything?

Stations that are still off the air or are broadcasting at a limited amount of power:

94.5 KFMX
98.1 KKCL
99.5 KQBR
102.5 KZII

Basically, as of now, all GAP stations are down. The strange thing is, they were working fine during the storm. Seems like today, they all suddenly shut down. I was barely able to pick up Kiss FM in my car next to the Texas Tech campus.

 

[Garrett]

KFYO was still on the air as of yesterday, so perhaps it only affected FM?

 

[EggsOverEasy87]

KFYO was still on the air as of yesterday, so perhaps it only affected FM?

Correction. All FM Gap Stations seem to be down. My mistake. The AM radio in my car doesn't work great, so I have no clue on how much the AM stations here in town were affected.

 

[BigVoiceGuy]

The storm itself wasn't the problem for GAP Fm's...The problem was the chunks of ice falling off the tower onto the xmitter building when the temps got above freezing. Since all 4 FM xmitters are at the same location, that's why all went dowm. KFYO and KKAM's xmitters are in different locations in two different parts of the city.

 

[DG]

And to add to BVG's comment...

For AM stations, the entire tower is the antenna, so ice won't have that much of an impact on them short of bringing the tower down due to weight.

Not so with FMs. Unless you have radomes or heating elements on the antenna bays, ice creates a very high reflected wave back to the transmitter, which can cause severe damage. Most rigs will decrease the output power to a manageable level or just shut down completely, which is what happened with 88.1.

There were numerous power outages too...

 

[Kent]

For AM stations, the entire tower is the antenna, so ice won't have that much of an impact on them short of bringing the tower down due to weight.

AM transmitters can also become detuned when coated with ice, but I understand we're still talking a significant amount of ice to make that happen. One of the engineers I used to work with also told me this was usually a temporary problem.

Not so with FMs. Unless you have radomes or heating elements on the antenna bays, ice creates a very high reflected wave back to the transmitter, which can cause severe damage. Most rigs will decrease the output power to a manageable level or just shut down completely, which is what happened with 88.1.

When I worked at a cluster of 3 FM's and an AM, one of the FM's had a solid state transmitter, and I was told this was far less of a problem on solid state transmitters than the tube type ones. We had to monitor the 2 FM's with tube type transmitters every 30 minutes during icing conditions because too much power reflected back to the transmitter could burn the filaments and/or overload the plate. The transmitter would shut off if the plate current got too high so as to prevent the filaments from burning up, but you'd pay for the lost business out of your own paycheck if the transmitter went down on your watch due to excessive icing!

 

[DG]

Not sure if SS rigs handle ice any better. I've always thought the opposite was true, but VSWR is VSWR regardless.

And we're running a 10kW SS Nautel rig on 88.1 and it was not happy at all in the ice Thursday.

I'm glad we got rid of our tube-type many years ago. Tuning those puppies with a newly rebuilt tube was real work!