Search found 514 matches

by Kelly
Sat Mar 16, 2019 5:29 pm
Forum: FM Radio
Topic: BE FM20A/B IPA Issue
Replies: 2
Views: 333

Re: BE FM20A/B IPA Issue

If it's never been done, I'd plan on replacing the big round filter caps in each of the IPA's. Those things when they go way out of value, will make the IPA's go into mute mode intermittently.
by Kelly
Mon Feb 04, 2019 1:20 pm
Forum: FM Radio
Topic: HT-10 APC issues
Replies: 12
Views: 707

Re: HT-10 APC issues

There are so many variables. Synchronous and Asynchronous AM noise are different but similar animals. If the APC is running the screen too low or high from where the tuning is resonant, that could cause increased Asynchronous AM noise. As jthorusen mentioned; if the APC is off and the transmitter tu...
by Kelly
Mon Feb 04, 2019 1:10 pm
Forum: TV Engineering
Topic: 4K/60Hz HDMI DA that works?
Replies: 5
Views: 343

Re: 4K/60Hz HDMI DA that works?

I echo what Jeff mentioned. That, and unless you're running cables that support HDMI 2.0, 50 feet may be pushing the length. Most HDMI DA's don't do any level boost, so if your input cable to the DA is causing any attenuation, that level is passed along on the output spigots. My bet is you'll probab...
by Kelly
Fri Feb 01, 2019 11:47 am
Forum: FM Radio
Topic: HT-10 APC issues
Replies: 12
Views: 707

Re: HT-10 APC issues

It's been a while, but I recall those Harris THE-1 exciters were plagued with microphonic tendencies from blower motor vibration. Besides being a pretty crappy exciter, they should at least be mounted apart from the transmitter.
by Kelly
Tue Jan 08, 2019 1:06 pm
Forum: FM Radio
Topic: BE FM-5BS PROBLEM
Replies: 5
Views: 394

Re: BE FM-5BS PROBLEM

Many moons ago I had something similar happen to a BE tube rig. After a lot of tracing, I discovered one of the bypass caps in one of the wires connecting between the controller and some solid state relays had shorted. The caps were soldered on a PC backplane board mounted in the aluminum shielding ...
by Kelly
Fri Dec 14, 2018 12:57 pm
Forum: Broadcast Engineering News
Topic: Tiger Mountain (WA) master antenna catches on fire
Replies: 20
Views: 1367

Re: Tiger Mountain (WA) master antenna catches on fire

This was a dual feed antenna, a top and bottom section so there would have to been two VSWR detectors for each transmission line going up the tower to the antenna. Another question is why was there no pressure monitor on each transmission line along with a run monitor on the pressurization system. ...
by Kelly
Wed Dec 12, 2018 5:57 pm
Forum: TV Engineering
Topic: Computer-controlled small L-band switches?
Replies: 9
Views: 778

Re: Computer-controlled small L-band switches?

For years I have dreamed of having a Quintech L-band routing switcher in our plant, but sadly I don't see it happening. Hey, I remember you guys in Syracuse always putting in for an L-Band router way back when I was in charge of capital for the company! You never did get one eh? Damn things were al...
by Kelly
Tue Dec 11, 2018 6:47 pm
Forum: FM Radio
Topic: ORBAN OPTIMOD-FM 8400 Display Problem
Replies: 3
Views: 188

Re: ORBAN OPTIMOD-FM 8400 Display Problem

I've got a good used Orban Optimod 8400 and one 8500 for sale if you're interested in replacing that one. PM me off the discussion for details.
by Kelly
Tue Dec 11, 2018 8:43 am
Forum: FM Radio
Topic: High Reflected Power Puzzle
Replies: 33
Views: 1320

Re: High Reflected Power Puzzle

We've all been bitten by this one: Check the center pins on both N-connectors. Depending on how they were installed and whether they were the solder-on type center pins or captive, the pin may have pulled back lightly into the connector. That could account for why sometimes it works and other times ...
by Kelly
Wed Dec 05, 2018 2:37 pm
Forum: TV Engineering
Topic: Need help with Sony BVH2500P
Replies: 6
Views: 1056

Re: Need help with Sony BVH2500P

As Jeff mentioned; chances are the motor is okay but there may be something wrong with the motor drive board. As I recall, there is a transistor that sometimes burns up. That, or some of those old capacitors have dried out to the point where they quit or their values are all out of whack. Trying to ...
by Kelly
Wed Dec 05, 2018 2:30 pm
Forum: FM Radio
Topic: 100 OHM 100W resistor in Harris HT35FM PA Cavity
Replies: 10
Views: 596

Re: 100 OHM 100W resistor in Harris HT35FM PA Cavity

There was a station across town that had an old BTF20 used as backup which we called The Blue Flame Special. Sometimes when you tune it or the exciter muted, it used to shoot a blue corona out the top. One day we were digging into it and discovered a similar swamping resistor was completely missing.
by Kelly
Tue Dec 04, 2018 4:42 pm
Forum: FM Radio
Topic: 100 OHM 100W resistor in Harris HT35FM PA Cavity
Replies: 10
Views: 596

Re: 100 OHM 100W resistor in Harris HT35FM PA Cavity

I believe that resistor is used as a corona swamping resistor. That's why the RF finger stock is around each end of the resistor.

Harris and RCA 1/4 wave cavity transmitters used various forms of these resistors to keep the PA for going into business for itself at startup.
by Kelly
Sun Nov 25, 2018 7:33 pm
Forum: FM Radio
Topic: ERI COG-1084 question
Replies: 8
Views: 476

Re: ERI COG-1084 question

Brand of transmitters in use for the three stations? Even at a relatively modest ERP (3200 watts) I noticed a dramatic decrease in multipath when I finally retired an old Haris 2.5H in favor of a solid state transmitter. Chances are what you noticed by going to a solid state TX is a reduction in am...
by Kelly
Thu Oct 18, 2018 5:37 pm
Forum: FM Radio
Topic: Harris Z FM-HD Problem
Replies: 5
Views: 553

Re: Harris Z FM-HD Problem

It's not a Z-series, but I have a that Importer/Exporter combination at one of my translator sites. Sometimes it requires a power-down restart of the importer/exporter and exciter together. Have you tried pulling the plugs, letting it sit for about :30? Seems like it loses the connection between all...