Search found 11 matches

by Tom Osenkowsky (RIP)
Wed Jul 26, 2017 5:38 pm
Forum: AM Radio
Topic: Bad hum
Replies: 6
Views: 1270

Re: Bad hum

Does this sound like 120 Hz power supply hum? An open power supply capacitor or is it hum as in an open shield on an audio cable? I would start with these answers first. A scope on the audio outputs section by section may be revealing. While it could also be caused by RF from one of the other transm...
by Tom Osenkowsky (RIP)
Tue Jul 04, 2017 6:13 pm
Forum: FM Radio
Topic: Orban Disk on Chip
Replies: 1
Views: 534

Re: Orban Disk on Chip

I know Kim and Bill (RIP) mainly did analog Optimods but Kim Sacks may be able to offer some insight:

radioctrldwife@gmail.com

-Tom
by Tom Osenkowsky (RIP)
Tue Jul 04, 2017 6:03 pm
Forum: AM Radio
Topic: Look what took my 50kw off the air
Replies: 6
Views: 1587

Re: Look what took my 50kw off the air

I was hired to represent a major transmitter in the capacity of a field service visit. No factory techs were available. The intermittent fault was in a new 3.5 kW FM transmitter. Yes, I know this is the AM section but the cause/solution is universally applicable. The problem was the tx would randoml...
by Tom Osenkowsky (RIP)
Wed May 31, 2017 6:54 pm
Forum: FM Radio
Topic: Nautel NV10LT
Replies: 21
Views: 3695

Re: Nautel NV10LT

My post is going to be about Nautel in general, not specifically the NV10LT with which I have no experience. Some years ago I had to replace a Harris FM3.5K at a University station. I had planned to purchase a Harris solid state transmitter. Due to the physical configuration of the transmitter and t...
by Tom Osenkowsky (RIP)
Tue Apr 25, 2017 5:57 pm
Forum: AM Radio
Topic: EO Pulsar 1KW problem
Replies: 9
Views: 1685

Re: EO Pulsar 1KW problem

Since you mention "melted" I would look at the fuse socket itself for signs of poor contact causing a heating condition. This has occurred in B.E. AM-5 transmitters, Excel tower light controllers and Crown 600E units. Resistance can cause heating between the holder and the fuse itself.
by Tom Osenkowsky (RIP)
Tue Nov 01, 2016 7:54 pm
Forum: AM Radio
Topic: Combining two AMs at one site
Replies: 24
Views: 2886

Re: Combining two AMs at one site

You must evaluate the entire project from both a business and technical perspective. There are component costs, labor costs for component installation and adjustment, DA retuning, DA proofing (conventional or MoM, if applicable), lease expenses, STL and miscellaneous costs. After due consideration i...
by Tom Osenkowsky (RIP)
Sun Sep 04, 2016 8:05 pm
Forum: AM Radio
Topic: Proper way to adjust ATU...
Replies: 13
Views: 2482

Re: Proper way to adjust ATU...

If you use the TOOLBOX program you don't need to know the math, the equations are already in the program. Your first step is to contact the manufacturer of your transmitter. Ask them what the optimal sideband impedances at +/- 10 kHz from carrier are at the transmitter antenna terminals. This is an ...
by Tom Osenkowsky (RIP)
Thu Aug 04, 2016 6:31 pm
Forum: AM Radio
Topic: Proper way to adjust ATU...
Replies: 13
Views: 2482

Re: Proper way to adjust ATU...

The phase shift of the ATU also affects bandwidth. The rotation of the sidebands with respect to the carrier is critical only at the RF generation point. This would be at the plate(s) of the final RF amplifier in a tube transmitter or at the PA combining point in a solid state transmitter. The manuf...
by Tom Osenkowsky (RIP)
Sat Jul 16, 2016 5:20 pm
Forum: AM Radio
Topic: Tower site grass control - will goats eat ground radials ?
Replies: 16
Views: 2378

Re: Tower site grass control - will goats eat ground radials ?

There is a company called Rent A Goat (http://rentagoat.com/) I saw a news piece where a park in Brooklyn, NY has placed goats there to mow the fields. I recall being in Aruba during a new tower erection and was tasked with shooing the neighbor's goats away from the newly laid ground radials. Their ...
by Tom Osenkowsky (RIP)
Sun Jun 26, 2016 4:06 pm
Forum: AM Radio
Topic: AM Transmitter distance to tower
Replies: 2
Views: 1063

Re: AM Transmitter distance to tower

If your station is non-directional (a single tower) you measure your power at the tower base. This is accomplished by reading the base current without modulation and multiplying that reading by itself and multiplying that number by the licensed base resistance, in other words I squared R. For exampl...