Search found 564 matches

by kcbooboo
Mon Sep 16, 2019 7:33 am
Forum: AM Radio
Topic: Equipment Performance Measurements
Replies: 3
Views: 120

Re: Equipment Performance Measurements

Thanks. I really don't know when the main will be back in full operation. I think they're using it at night when they run lower power, then switching to the backup during the day for better coverage. They already sent two RF modules to BE for repair and that took 3-4 weeks. When they came back, one ...
by kcbooboo
Sun Sep 15, 2019 1:08 pm
Forum: AM Radio
Topic: Equipment Performance Measurements
Replies: 3
Views: 120

Equipment Performance Measurements

It's that time of year again. One of the stations I do spectrums for, is running on their backup TX because the main has one PA module out for repair. Does it matter if I take spectrums while they're on the backup TX as long as I document the conditions that existed at the time, or should I wait for...
by kcbooboo
Fri Aug 30, 2019 6:24 am
Forum: Ask the Engineers
Topic: Marti Crystals
Replies: 6
Views: 327

Re: Marti Crystals

The biggest hurdle will be getting new crystals. International Crystal Mfg closed. Bomar isn't really an option. Your best bet would be to send the oscillator schematic and maybe even an old crystal to http://www.quartslab.com/ QuartsLab over in England. I've worked on a couple of Marti units. They'...
by kcbooboo
Sun Aug 25, 2019 5:16 am
Forum: FCC Discussion
Topic: AM station to shut down at end of May 2019
Replies: 23
Views: 1219

Re: AM station to shut down at end of May 2019

Apparently they filed a "Silent STA". I don't know if that's the same as surrendering the license. I also heard that they inquired about taking the towers down. That pretty much means they'll be selling the equipment and property pretty soon afterward.

Bob M.
by kcbooboo
Sat Aug 17, 2019 7:15 am
Forum: Ask the Engineers
Topic: Belar FMS-2 Meters
Replies: 13
Views: 451

Re: Belar FMS-2 Meters

On an AM mod monitor the linearity past 100% could be questionable depending on the demodulation scheme, but I'd hope that the demod is linear on FM out to 100 kHz. You could also attach an external meter of almost any kind to the FMS-2 and compare its actual uA readings with the front panel meters....
by kcbooboo
Fri Aug 16, 2019 7:29 am
Forum: Ask the Engineers
Topic: Belar FMS-2 Meters
Replies: 13
Views: 451

Re: Belar FMS-2 Meters

I took a look at the manual. I didn't see any zero-adjust pots inside, which led me to believe the front panel meters are simply AC voltmeters and are supposed to sit at zero with power turned off. Some of the Belar products do use center-zero meters, such as those that also indicate FM pilot freque...
by kcbooboo
Fri Aug 16, 2019 7:17 am
Forum: AM Radio
Topic: finding AM ground radials
Replies: 41
Views: 4363

Re: finding AM ground radials

Interesting that this thread picked up activity. The station is up for license renewal and can't continue to get STAs, so the corporate DA engineer is around the area to finally finish the array setup. They measured each tower again; the two end towers (self-supporting) had identical base Z; the two...
by kcbooboo
Thu Aug 08, 2019 3:26 am
Forum: FM Radio
Topic: National EAS Test
Replies: 16
Views: 502

Re: National EAS Test

I was working at the bench listening to the Mets game on WCBS/880. It seemed an odd time for an EAS test but it sounded like almost every other EAS test I've heard, just a bit longer and with tons of compression and increased noise level, as if it had been repeated and processed several times, not l...
by kcbooboo
Mon Aug 05, 2019 4:03 am
Forum: FM Radio
Topic: RDS Question
Replies: 12
Views: 337

Re: RDS Question

So what does that mean for a translator that's picking up the primary station's HD2 signal OTA with an HD receiver and retransmitting that as a low-power analog stereo FM signal on another frequency? Where does the RDS data come from? Or isn't this a true translator in the sense that the baseband si...
by kcbooboo
Wed Jul 31, 2019 5:43 am
Forum: FM Radio
Topic: Continental 816-R2 air chimney screws
Replies: 5
Views: 146

Re: Continental 816-R2 air chimney screws

I don't even recall seeing screws that hold that white plastic plate to the aluminum RF cavity. They could have used nylon screws from underneath. But it definitely IS thicker than 1/8. I'll have to bring a camera with me next time. I did order some #4-40 screws with larger heads that still have an ...
by kcbooboo
Tue Jul 30, 2019 3:11 pm
Forum: FM Radio
Topic: Continental 816-R2 air chimney screws
Replies: 5
Views: 146

Re: Continental 816-R2 air chimney screws

Thanks. As I recall, the white plastic plate that the chimney screws are threaded into looks to be about 3/8 inch thick, at least at the edges of that plate, which is probably 10x10 inches, maybe bigger. It may be milled thinner where the chimney screws are threaded into it. I don't know whether the...
by kcbooboo
Tue Jul 30, 2019 9:38 am
Forum: FM Radio
Topic: Continental 816-R2 air chimney screws
Replies: 5
Views: 146

Continental 816-R2 air chimney screws

When replacing the 4CX15,000 PA, one must remove the split air chimney by removing four #4-40 nylon screws that hold the chimney to the tube socket plastic baseplate. These screws always seem to be breaking off, sometimes leaving a little bit in the threaded hole. Fortunately these usually come righ...
by kcbooboo
Mon Jul 15, 2019 4:04 am
Forum: FM Radio
Topic: Harris Z FM FET replacement
Replies: 7
Views: 380

Re: Harris Z FM FET replacement

"Nautel advises 6 INCH pounds of torque on their pallets. Yes---INCH/Pounds. There are 16 inch pounds to a foot pound."

There are 16 ounces per pound but only 12 inches per foot.

Perhaps you mean there are 12 (twelve) inch pounds to a foot pound, since there are 12 inches in a foot.

Bob M.
by kcbooboo
Wed Jul 10, 2019 4:36 pm
Forum: FM Radio
Topic: Replacement dehydrator pressure switch
Replies: 2
Views: 167

Re: Replacement dehydrator pressure switch

I googled: adjustable pressure switch and got several decent suppliers with units in the 3-6psi range for between $50 and $150. I also googled: Johnson Controls P61AA-35C and found one supplier that claims to have one unit in stock for around $35. You might try MSC instead of Grainger. Bob M.
by kcbooboo
Wed Jul 10, 2019 5:50 am
Forum: AM Radio
Topic: BE AM-6A RF Out Problem
Replies: 19
Views: 625

Re: BE AM-6A RF Out Problem

As I recall, the ATU isn't the easiest unit to get into for "routine" maintenance. However if you DO get inside it, make sure the roller inductor rotating shafts are clean and lubricated with an appropriate grease so they don't jam up. Had that happen one night. Couldn't get the roller shaft out wit...