Search found 3374 matches

by Deep Thought
Wed Dec 05, 2018 1:06 am
Forum: FM Radio
Topic: Horizontal or vertical
Replies: 4
Views: 174

Re: Horizontal or vertical

Look at the Scala HDCA-5CP/RM, which is a 5 element circularly-polarized yagi. There are two smaller models as well, all rated for 250 watts. Those Yagis have a lot off the backside. You can combine a V and H pol log periodic using a power divider. Scala routinely does these. It'll take up twice th...
by Deep Thought
Tue Nov 20, 2018 10:09 pm
Forum: AM Radio
Topic: KYFR AM tower light monitor
Replies: 16
Views: 671

Re: KYFR AM tower light monitor

kkiddkkidd wrote:
Tue Nov 20, 2018 6:24 pm
ChuckG wrote:
Mon Nov 19, 2018 10:57 pm


When you ask how they monitor the tower lights and they show you the swing in the phase monitor corresponding to the beacons...... :lol:
Now that's funny right there...
Funny and far too common. :mrgreen:
by Deep Thought
Sun Nov 18, 2018 11:07 am
Forum: AM Radio
Topic: KYFR AM tower light monitor
Replies: 16
Views: 671

Re: KYFR AM tower light monitor

Sounds like the tower I "discovered" was 120 VAC above ground when I connected my OIB-3. I think I scared the cows that night. :shock: I don't recall ever finding a tower with hard 120v on it but have found several that had enough leakage to light you up if the static drain was disconnected. After ...
by Deep Thought
Sun Nov 18, 2018 12:11 am
Forum: AM Radio
Topic: KYFR AM tower light monitor
Replies: 16
Views: 671

Re: KYFR AM tower light monitor

Sounds like the tower I "discovered" was 120 VAC above ground when I connected my OIB-3. I think I scared the cows that night. :shock:
by Deep Thought
Wed Nov 14, 2018 9:56 am
Forum: AM Radio
Topic: KYFR AM tower light monitor
Replies: 16
Views: 671

Re: KYFR AM tower light monitor

I've done it with current transformers and a comparator circuit set to trigger on an alarm condition based on overall current draw. I used a LM3914 which gave me multiple "taps" to show the beacon and sidelights, and as a bonus showed the beacon flash as well. The remote display had two LEDs per tow...
by Deep Thought
Tue Nov 13, 2018 10:31 pm
Forum: Broadcast Engineering News
Topic: Tiger Mountain (WA) master antenna catches on fire
Replies: 20
Views: 834

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

NECRAT wrote:
Tue Nov 13, 2018 8:56 am
Instead of speculating, we could also just wait for the report to come out as to the cause.
Meh...what fun is that? :mrgreen:
by Deep Thought
Mon Nov 12, 2018 2:37 pm
Forum: AM Radio
Topic: ATU rebuild
Replies: 21
Views: 739

Re: ATU rebuild

Here you go. I ran it twice, once with a base impedance close to what the measured data shows and once with the theoretical base impedance. You can match either with the same components. The current ratings need to be multiplied by 1.6 and the voltage ratings need to be multiplied by 6.0 to account ...
by Deep Thought
Mon Nov 12, 2018 8:30 am
Forum: AM Radio
Topic: ATU rebuild
Replies: 21
Views: 739

Re: ATU rebuild

What is the transmission line length? I can take that into account when adjusting the network for best bandwidth at the transmitter end.
by Deep Thought
Sat Nov 10, 2018 2:54 pm
Forum: Broadcast Engineering News
Topic: Tiger Mountain (WA) master antenna catches on fire
Replies: 20
Views: 834

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

Looked to me like a radome fire...the top few seem intact. However they don't just go up on their own so something lower got damn hot.
by Deep Thought
Thu Nov 08, 2018 8:24 pm
Forum: AM Radio
Topic: ATU rebuild
Replies: 21
Views: 739

Re: ATU rebuild

I'll accept either a whine or a beg. No need to go overboard. :mrgreen:

If you give me a description of the tower and what is on it, I can model it and get pretty close to the right phase shift for optimum bandwidth without having to do a full sweep.
by Deep Thought
Wed Nov 07, 2018 10:34 am
Forum: AM Radio
Topic: ATU rebuild
Replies: 21
Views: 739

Re: ATU rebuild

DO NOT--repeat--DO NOT try to do this with a "single coil" network. It will be unstable as hell, almost impossible to tune due to the stray reactances and cross coupling between the turns on the coil, and will have shit for bandwidth. I will be happy to send you a proper design for free just to save...
by Deep Thought
Sat Nov 03, 2018 10:54 pm
Forum: Everything else
Topic: Wireless Mics and the Repack
Replies: 2
Views: 120

Re: Wireless Mics and the Repack

grich wrote:
Sat Nov 03, 2018 9:56 pm
We've already replaced equipment that operated above channel 36, right? :wink:
I'm sure T-Mo won't mind sharing... :mrgreen:
by Deep Thought
Sat Nov 03, 2018 10:52 pm
Forum: FCC Discussion
Topic: Knife edge limits for § 15.221 Operation in the band 525-1705 kHz.
Replies: 2
Views: 225

Re: Knife edge limits for § 15.221 Operation in the band 525-1705 kHz.

The perimeter is the outermost property line. As a practical matter, unless you are going to deploy multiple transmitters the limit will be imposed at the point on that perimeter closest to the antenna.
by Deep Thought
Thu Oct 18, 2018 8:49 am
Forum: AM Radio
Topic: Gates 5 rebuild
Replies: 10
Views: 975

Re: Gates 5 rebuild

Otherwise, the basics apply to this rig... keep it clean, keep it cool, visit it once in a while. They also really *really* don't like open delta power feeds. One client was replacing fuses and FETs on a monthly basis until they installed a delta-to-wye transformer and haven't had a major problem s...
by Deep Thought
Wed Oct 10, 2018 9:16 am
Forum: FCC Discussion
Topic: Does the FCC keep track somewhere of subchannels?
Replies: 3
Views: 361

Re: Does the FCC keep track somewhere of subchannels?

The FCC only tracks stations running in a digital mode (assuming you're talking about FM) and not how many or what is on the subchannels.

Digital TV is licensed as such, but the FCC does not track the 'dot' channels deployment.