Search found 110 matches

by COMMENG
Wed Oct 17, 2018 10:01 pm
Forum: AM Radio
Topic: Harris Digital Z HD Issues
Replies: 1
Views: 117

Re: Harris Digital Z HD Issues

You might get more visibility if you post your question in the FM thread:

viewforum.php?f=3



COMMENG
by COMMENG
Wed Sep 12, 2018 2:05 pm
Forum: AM Radio
Topic: Crystal alternative
Replies: 17
Views: 940

Re: Crystal alternative

Micheal Paton from Baton Rouge, La. had a device for some of the Harris AM transmitters. I think he said it could be set via dip switch to output a frequency of .5 to 5Mhz. I saw the board he had at the Alabama Broadcasters Association convention and it looked professionally made and the price wasn...
by COMMENG
Tue Sep 04, 2018 11:52 am
Forum: AM Radio
Topic: Crystal alternative
Replies: 17
Views: 940

Re: Crystal alternative

What is the required holder/mounting and is this a parallel resonant or series resonant crystal circuit? I posted one such potential solution here: https://broadcastengineering.info/viewtopic.php?f=2&t=6345 Some crystals can still be had from: http://www.af4k.com/crystals.htm Another solution is to ...
by COMMENG
Wed Jun 20, 2018 3:08 pm
Forum: TV Studio Engineering
Topic: Weather Radar
Replies: 7
Views: 663

Re: Weather Radar

If you can afford it, an S band radar system is the way to go. We're fortunate to have an S band radar system giving us feed compliments of my former avionics company. The S band system gives extremely good detail within 50 miles (much better than NOAA), precipitation, cloud height information, and ...
by COMMENG
Wed Jun 13, 2018 2:10 pm
Forum: FM Radio
Topic: FM and windmills
Replies: 6
Views: 349

Re: FM and windmills

We have a bunch of windwmills up here in Iowa, in fact many of the components are made in Cedar Rapids. I have been told the blades are made of an aluminum core with fiberglass skins. The width of the cores are about 1/8 wavelength wide so I doubt you will have any problems if they are 1 mile or mor...
by COMMENG
Wed Jun 13, 2018 1:58 pm
Forum: AM Radio
Topic: Restoring a small transmitter
Replies: 24
Views: 5029

Re: Restoring a small transmitter

Thanks for the comments and the advices I will try the mouser site to see if I can obtain those capacitors. For the linear info. I would have to open the amp to see what is inside. I'm sure He had done some modifications. I'll try when I have the opportunity to go on the site where they are. But, I...
by COMMENG
Thu Jun 07, 2018 2:35 pm
Forum: AM Radio
Topic: AM Tuning Unit Design Software
Replies: 9
Views: 463

Re: AM Tuning Unit Design Software

Hi all, I have a number of free & cheap pieces of software that includes Tee-net design. However, it appears that a couple of my favorites don't run (or don't run correctly) in Win10 and I am about to have to move to Win10 on a new Toughbook AND have 3 or 4 small tuning projects coming up quickly. ...
by COMMENG
Thu Jun 07, 2018 2:31 pm
Forum: AM Radio
Topic: Restoring a small transmitter
Replies: 24
Views: 5029

Re: Restoring a small transmitter

Hi, I'm truly sorry and I have once again to apologize for the big delay in my answers, I had lost my password among other situation like moving. Ok yes I will try to find out about the power amp- it's an Ameritron i think the final tubes are 811. still having difficulties to find the capacitors 23...
by COMMENG
Fri May 04, 2018 11:40 am
Forum: AM Radio
Topic: Need Crystal for LPB-30
Replies: 1
Views: 265

Re: Need Crystal for LPB-30

Yiu might try:

http://www.af4k.com/crystals.htm (see center of Page)

and resort to a circuit shown below, or purchase a DDS kit:

Remove A3 and Feed the squarewave RF to pin 8.
by COMMENG
Thu Apr 19, 2018 12:07 am
Forum: Everything else
Topic: A bit of AM History
Replies: 4
Views: 321

A bit of AM History

My first BE job was taking care of a number of these beasts for some hometown AM Stations in OK, MO, and KS.

BTW, they sounded this good.

https://www.youtube.com/watch?v=0VYDBFDiPZY


COMMENG
by COMMENG
Tue Jan 09, 2018 10:38 am
Forum: AM Radio
Topic: What is this? A 5 kw Dummy Load or what?
Replies: 22
Views: 3094

Re: What is this? A 5 kw Dummy Load or what?

The "resistive" strip appears to have come from an older Gates BC-1T or similar vintage vacuum tube transmitter. I agree - I have a BC-1T load here and it appears identical. Bear in mind that a BC-1T load is not a 50 ohm load - it is a 51.5 ohm load. It's still a 50 ohm dummy load, in the vernacula...
by COMMENG
Mon Jan 08, 2018 10:51 am
Forum: AM Radio
Topic: What is this? A 5 kw Dummy Load or what?
Replies: 22
Views: 3094

Re: What is this? A 5 kw Dummy Load or what?

The "resistive" strip appears to have come from an older Gates BC-1T or similar vintage vacuum tube transmitter.

Each resistor is most likely rated at 412 ohms, 150 Watts or so.

The other other stuff appears to be added on to get to J0.

COMMENG
by COMMENG
Mon Dec 25, 2017 9:56 am
Forum: Everything else
Topic: Merry Christmas
Replies: 7
Views: 570

Re: Merry Christmas

Merry Christmas to all.

We had about 2" of snow here in the Central Midwest as the temp plunged to about 10F this morning. :shock:

May you have a Joyous and prosperous New Year! :D

COMMENG
by COMMENG
Thu Dec 21, 2017 12:25 pm
Forum: FM Radio
Topic: RF Spectrum Analyzer
Replies: 26
Views: 1803

Re: RF Spectrum Analyzer

Who, or what agency has "ASKED" you to do this. And just what is "second harmony"?? Fossil It is a regulatory agency within Canada, they are responsible for "Spectrum Management"; because of proximity to an airport, they are asking for more detailed scans. I'm thinking that the "2nd harmony" is ref...
by COMMENG
Wed Nov 15, 2017 11:03 am
Forum: FM Radio
Topic: FM range question - coastal mountainous terrain
Replies: 23
Views: 1789

Re: FM range question - coastal mountainous terrain

Is there some reason you can't move the transmitting facilities to the Nieves Peak area somewhere along GC 134 (such as the San Bernardo refuge) and increase power to 5kW? I concur with Deep Thought, your major problem here is obstructions from volcanic landforms with the resulting wave reflections,...