Search found 3448 matches

by Deep Thought
Mon Nov 11, 2019 8:19 pm
Forum: AM Radio
Topic: Asymmetrical modulation
Replies: 76
Views: 18028

Re: Asymmetrical modulation

rfn wrote:
Mon Nov 11, 2019 10:00 am
And there is why I carry a phase-shifting XLR/XLR when doing work for stations using asymmetric modulation.
All that does is invert the audio. It does not address the underlying issue.
by Deep Thought
Mon Nov 11, 2019 12:47 am
Forum: AM Radio
Topic: Asymmetrical modulation
Replies: 76
Views: 18028

Re: Asymmetrical modulation

6+ year old zombie thread walks like zombie. ;) I still stand by my (and many other's) assertion that all you add with that much asymmetrical modulation is distortion in the receiver. There is no way to avoid it and all that even order THD and intermodulation distortion just muddies up the audio, wh...
by Deep Thought
Thu Sep 26, 2019 10:38 pm
Forum: AM Radio
Topic: Gates 5 PA Low Amps
Replies: 4
Views: 197

Re: Gates 5 PA Low Amps

Can you peak the PA current by changing the tuning adjustment? There are parts of the output network which are "before" the VSWR detector and can shift the tuning point if they fail. L1/C1, L2/C2. From the manual: 4.9. Causes for a PA Volts/PA Amps Ratio Change This discussion covers causes which mi...
by Deep Thought
Wed Sep 25, 2019 11:51 am
Forum: TV Engineering
Topic: TV OTA antennas
Replies: 9
Views: 586

Re: TV OTA antennas

Nothing. Why would they if the older wideband designs work?
by Deep Thought
Tue Sep 24, 2019 11:15 pm
Forum: TV Engineering
Topic: TV OTA antennas
Replies: 9
Views: 586

Re: TV OTA antennas

Any old-school "fishbone" antenna is always your best bet unless you are UHF-only. Then a four bay bow tie will win just about every time.

The "new" antenna designs are really bad. I tried one of the "Leaf" antennas when they came out and a simple UHF loop did a better job.
by Deep Thought
Tue Sep 24, 2019 10:01 pm
Forum: FCC Discussion
Topic: FM Filings now on LMS
Replies: 0
Views: 529

FM Filings now on LMS

FCC Note: As of midnight tonight CDBS filing for forms 301-FM, 302-FM, 318, 319, 340, 349, and 350 are moved to LMS.

https://enterpriseefiling.fcc.gov/dataentry/
by Deep Thought
Sun Sep 15, 2019 1:21 pm
Forum: AM Radio
Topic: Equipment Performance Measurements
Replies: 6
Views: 440

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: 284

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: 387

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: 9
Views: 431

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: 9
Views: 431

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: 1411

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: 625

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: 625

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: 625

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.