Search found 3442 matches

by Deep Thought
Sun Sep 15, 2019 1:21 pm
Forum: AM Radio
Topic: Equipment Performance Measurements
Replies: 3
Views: 182

Re: Equipment Performance Measurements

The NRSC mask compliance measurements are to be taken no more than 14 months apart. Will the main transmitter be back online before the 14 months ends? Also, §73.1590(b) Measurements for spurious and harmonic emissions must be made to show compliance with the transmission system requirements of §73....
by Deep Thought
Wed Aug 28, 2019 9:33 am
Forum: Everything else
Topic: Political Candidates & Talk Show Host
Replies: 4
Views: 264

Re: Political Candidates & Talk Show Host

Until he officially files he can continue doing what he has been doing. Salem has already sent notice to other stations that the syndicated version of his show is ending in the next 30 days, but the local version on WIND will continue until he is officially a candidate. Knowing his past, it is about...
by Deep Thought
Mon Aug 26, 2019 11:28 pm
Forum: AM Radio
Topic: Sample lines: curiosity question
Replies: 4
Views: 341

Re: Sample lines: curiosity question

A lot of old (>40 years) systems used RG-8 which has issues with temperature stability and is not really an FCC favorite. When the Commission standardized on a "type approved sample system" they specified solid outer conductor (shield) cable which can be phase stabilized by heating for a period of t...
by Deep Thought
Mon Aug 26, 2019 8:00 pm
Forum: AM Radio
Topic: Replacing sample lines
Replies: 8
Views: 183

Re: Replacing sample lines

I've switched out those Harris motorized contactors with KTL units directly without needing to use slave relays. The Harris phasor controller shoots 240 VAC out to them through the control cable for (I think) a maximum of 5 seconds and the status returns should be compatible with the KTL microswitch...
by Deep Thought
Mon Aug 26, 2019 5:30 pm
Forum: AM Radio
Topic: Replacing sample lines
Replies: 8
Views: 183

Re: Replacing sample lines

Cablewave 3/8" FCC38-50J is 81% while Andrew LDF4-50 is 88% velocity. Bad things happen when you replace one with the other. Andrew FSJ4-50B is 81% but is really too fragile for long runs. From an FCC standpoint, the lines must measure equal in electrical length within 1% and within 2 ohms character...
by Deep Thought
Sun Aug 25, 2019 12:13 pm
Forum: FCC Discussion
Topic: AM station to shut down at end of May 2019
Replies: 23
Views: 1257

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

There is no STA for surrendering the license since it is not "temporary". The station just submits a letter with the license (or a copy of the original) and requests that it be cancelled. In this case it appears they're still hoping that someone will buy it if they are filing for STA to remain silen...
by Deep Thought
Wed Aug 21, 2019 11:22 pm
Forum: AM Radio
Topic: UNI
Replies: 14
Views: 557

Re: UNI

There is some talk of a tower replacement (it's pushing 50 in Arctic conditions) and along that will go some design work to see if a little shorter tower can be used 230 feet is 65.6° at 780 KHz and that station is licensed at 290 mV/m/km/kw. The FCC recently reduced the minimum efficiency requirem...
by Deep Thought
Sat Aug 17, 2019 6:46 pm
Forum: AM Radio
Topic: UNI
Replies: 14
Views: 557

Re: UNI

I'm surprised they allowed that, but then again this is a class-C channel and they really don't give a crap about nighttime radiation characteristics for those.
by Deep Thought
Fri Aug 16, 2019 10:14 pm
Forum: AM Radio
Topic: UNI
Replies: 14
Views: 557

Re: UNI

I don't think that's a feed skirt...I suspect that wire is the entire antenna and is not connected at the top. Performance probably sucks bigly.

The FCC won't authorize a single wire shunt feed anymore.
by Deep Thought
Fri Aug 16, 2019 8:48 pm
Forum: FCC Discussion
Topic: Fake EAS tones: ABC should know better...
Replies: 9
Views: 295

Re: Fake EAS tones: ABC should know better...

one of the things that FCC license study guides used to emphasize was the importance of being prompt and forthcoming in your dealings with the commission, especially after something has gone wrong. I doubt that an opaque reply nearly two months after the incident helped their cause, either. Indeed....
by Deep Thought
Fri Aug 16, 2019 11:27 am
Forum: Ask the Engineers
Topic: Belar FMS-2 Meters
Replies: 13
Views: 453

Re: Belar FMS-2 Meters

Those are custom scale meters so I would guess that Belar used that to compensate for something in the electronics or mechanics of the meter itself.
by Deep Thought
Fri Aug 16, 2019 11:24 am
Forum: FCC Discussion
Topic: Fake EAS tones: ABC should know better...
Replies: 9
Views: 295

Re: Fake EAS tones: ABC should know better...

The rule is very specific, so that response probably cemented the NAL using the "smartass policy". §11.45 Prohibition of false or deceptive EAS transmissions. (a) No person may transmit or cause to transmit the EAS codes or Attention Signal, or a recording or simulation thereof, in any circumstance ...
by Deep Thought
Thu Aug 15, 2019 8:17 pm
Forum: AM Radio
Topic: finding AM ground radials
Replies: 41
Views: 4373

Re: finding AM ground radials

The ones I have built over the years just used a 1N34 and a 100 uA meter and I still had to turn the pot down quite a bit. I have another that I used to measure current distribution on a tower but that one needed a 1 mA meter due to the much higher field values right at the tower even at very low po...
by Deep Thought
Tue Aug 13, 2019 3:22 pm
Forum: AM Radio
Topic: Porcelain Insulators Cracking
Replies: 5
Views: 250

Re: Porcelain Insulators Cracking

I agree with Fossil. If you don't use the fiber washers they'll crack from thermal expansion. Also, make sure there are the proper number of standoff insulators on coils...small 10 amp coils can get away with just two--one each in the middle of the frame--since those are pretty light, but anything b...
by Deep Thought
Sat Aug 10, 2019 11:10 pm
Forum: FM Radio
Topic: National EAS Test
Replies: 16
Views: 506

Re: National EAS Test

Part of the problem here is that the system is designed to be a "scorched earth last resort" relay which doesn't rely on external infrastructure to get the word out. This is a noble goal, but unfortunately broadcasting is an ignoble business. If stations truly operated in the public interest they'd ...