A little transmitter "feature"

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Re: A little transmitter "feature"

Post by okcradioguy » Thu Jan 09, 2014 11:25 am

"In Nautels' defense, it probably doesn't get this cold in Canda!"

I guess that's the irony of the mistake in their firmware. Of all the manufactures, one would think they'd have that test proceedure. Oh well.... Hopefully they have a fix for the glitch. It's hard to catch all the bugs I guess....

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Re: A little transmitter "feature"

Post by KPJL FM » Thu Jan 09, 2014 12:07 pm

awsherrill wrote:I would guess a clip-on work light stuck in the bottom of a rack (with an incandescent light bulb, of course) would provide enough heat to keep critical stuff working. If there's room inside the Nautel cabinet, maybe stick one in there also.

I recall doing this at sites where we had all solid-state rigs, when I worked in the Midwest years ago.
Reminds me of a story my (late) Dad told me about the reason for a 100 watt light bulb in every traffic controller box since the days of the transistorized loop actuators. The short of it: A new controller was going out every night in a Chicago suburb. Factory sent a tech to find out why. As the evening went on, the controller quit. He'd open the box, hang up a trouble light, and in a few minutes the controller went back to normal. After the second night of this, he installed a thermostat and a lamp socket, put in the 100 watt bulb. No more problem. Became standard equipment in the controllers ever since.
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Re: A little transmitter "feature"

Post by TPT » Thu Jan 09, 2014 5:39 pm

Of course, you can't get 100 watt incandescent bulbs anymore...

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Re: A little transmitter "feature"

Post by awsherrill » Thu Jan 09, 2014 5:42 pm

116-watt incandescent side marker lights will work just fine...haven't had any problems buying those.

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Re: A little transmitter "feature"

Post by Shane » Thu Jan 16, 2014 10:14 pm

Hey Allen,

I used that trick at KCRO one winter. I can't remember what piece of gear was giving me trouble but someone had made a light bar out of a 2X4 and a couple or three flood lamps so I stuck it in the rack under the offending gear.

Now I have a Nautel J1000 at another site that appears to have the same or similar control circuitry so I wonder if it would do the same thing. This site has heat so I might not ever find out unless the heat fails.
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Re: A little transmitter "feature"

Post by awsherrill » Thu Jan 16, 2014 11:17 pm

Hey Mike:

Glad it worked out for you. I had a Burk remote control in Tucson that would act up if the temps dropped into the 30s, so I would put a light under it and it would stay happy.

The only time I can remember having a transmitter act up in sub-zero temperatures was at the 1180 site in Council Bluffs. We were running an SX-5 with a BE AM stereo exciter in a separate rack, and the exciter started to fold up when the outside temps dropped to somewhere around -20. I moved the jumper in the SX so that it ran off the internal oscillator, and all was good again.

I sure don't miss Midwestern winters...I've been in Denver most of this week and they are having a heat wave! Daytime highs in the 50s.

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Re: A little transmitter "feature"

Post by stephend2 » Sat Jan 18, 2014 12:04 am

Have a CSI T-1-A that didn't complain a bit about the coldest couple nights in its existence recently. Was down to 12 F one night and 15 another, matching a record I think in 1974, before this transmitter was built in 1981. It lives at ambient temperature year round, installed before my time, I was made in '84.. New building going up at that site this year, planning a damper system to divert exaust inside when needed for heat, trying to get air conditioning and possibly a new solid state transmitter but sounds like the owner wants to keep the tube beast in operation until it wont go anymore.

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Re: A little transmitter "feature"

Post by RFWarrior » Tue Feb 18, 2014 8:51 pm

ChuckG wrote:
Deep Thought wrote: What gets me about Chris' scenario is that the computerized monitoring took the transmitter down, not an actual fault. Didn't we learn anything with the SX series AM transmitters? This sort of thing should not be happening and Nautel needs to fix it pronto.
In Nautels' defense, it probably doesn't get this cold in Canda! :mrgreen:
To wake this thread up again, I suspect it had more to do with the condensation that occurs on heat producing parts when ambient is below freezing. How are we supposed to fix people running equipment outside of specified operating parameters? Just curious :)
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Re: A little transmitter "feature"

Post by Deep Thought » Tue Feb 18, 2014 9:53 pm

You make sure the firmware can handle all of the conditions, including those which are outside spec. Having the monitoring system piss itself due to an error like this really isn't the customer's fault.
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Re: A little transmitter "feature"

Post by BroadcastDoc » Wed Feb 19, 2014 2:29 pm


I have to side with Mark on this one - if the transmitter is going to fault because it falls out of spec, the alarm had better show what spec it fell out of. In this case it didn't. It failed because the programming assumed that the transmitter wouldn't ever hit an ambient temp of 0*C, and yet it did. It doesn't help a tech if they go chasing an alarm that is actually isn't what it states! If the intention is to reduce the TX power due to the ambient temp falling below spec, then the alarm should state that.

The point here is that the alarm wasn't operating properly. It triggered not because of the ambient temp, but because a bug threw the controller into confusion.

While you can't fix people running stuff outside of the parameters, you can fix the transmitters ability to inform them that they're trying to run the transmitter outside of the parameters! :wink:
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Re: A little transmitter "feature"

Post by TPT » Wed Feb 19, 2014 6:14 pm

Hazard of having IT people get into broadcast design--all they've seen are server rooms that are kept at a perpetual 64 degrees.

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Re: A little transmitter "feature"

Post by jeeisenz » Sat Jun 14, 2014 9:17 am

BroadcastDoc wrote: So new mental note: Don't let the room temp drop below 32*!
Been there, done that late this winter. At a paticular station, it's FM-10T popped off. Ran up to the hill, and mind you it was MIGHTY cold (like probably -10 or so) - shack was just a hair under freezing. Seems that the 250 watt exciter doesn't like that. Exciter wouldn't come out of mute. 'Bout 15-20 minutes of a space heater blowing on it later it was warm enough to come back up. Transmitter made 100%, building warmed up pretty quickly after that. We put a heater in the building this spring so shouldn't be a problem anymore.

Had a similar problem with an FM-20K - can't remember why it was off, but the building was pretty dang cold. Got it going, ran it into the dummy load to warm up the building up a tad. At least they make a great heater! :lol:

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Re: A little transmitter "feature"

Post by kcbooboo » Sat Jun 14, 2014 1:03 pm

It gets much worse if any of your tx site equipment has computer hard drives in it. These have a low temp of 5C/40F, so you almost have to keep the building above freezing. Desktop computers, some remote control systems, some HD stuff like DexStars, must be kept warm. The actual transmitters probably don't care and they might very well work down to 0F. I know that the Harris DAX-1 will run fine at 0F as will a Harris MW-1A, although the personnel might not be happy. It just seems counterproductive to require 3kw of heaters in a small poorly insulated building that only has a 1kw AM transmitter, just to keep the hard drives running and happy.

Most companies that do software development also have test procedures and quality control departments. One of their jobs should be to test what happens in extremes or unexpected conditions, like when a temperature goes below 0C. The person who wrote the software probably knows exactly what will happen and what conditions are not tested, and will automatically avoid putting in bad data because he/she knows it's not handled. That's why there's usually a different person doing the testing, one who's not familiar with the conditions under which it will fail.

Bob M.

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