Search found 454 matches

by kcbooboo
Tue Dec 12, 2017 7:10 am
Forum: FM Radio
Topic: BE FM 25T Wandering Readings
Replies: 4
Views: 200

Re: BE FM 25T Wandering Readings

It doesn't take much RF floating around to upset the analog readings. I have a site with a 1kw AM TX in the adjacent rack and the tower about 50 ft away, and EVERY analog input has a 10uF 25V electrolytic cap across its screw terminals. That at least made the readings usable. A divider/filter as rec...
by kcbooboo
Sun Nov 19, 2017 4:13 am
Forum: STL Engineering
Topic: Women Hearing Distorsion on Station After STL realign
Replies: 20
Views: 768

Re: Women Hearing Distorsion on Station After STL realign

Imagine if iPhones had CRTs. People wouldn't be able to text and drive, text and walk, or text while doing anything else. What a world! Battery life would be specified in minutes. No more cracked faceplates from putting the phone into your back pocket and sitting down.

Bob M.
by kcbooboo
Tue Oct 31, 2017 5:20 am
Forum: Radio Studio Engineering
Topic: Arrakis 12,000 series console issues
Replies: 7
Views: 333

Re: Arrakis 12,000 series console issues

I don't know if your console has this, but I've seen some that use Molex connectors that have an "effects loop" on every input that must be jumpered if there is no external processor or other gizmo. If all the wires were just cut off, there could be some that just need to be connected together on so...
by kcbooboo
Wed Oct 25, 2017 1:31 pm
Forum: FM Radio
Topic: Nautel NV20 repair/restoration
Replies: 19
Views: 1617

Re: Nautel NV20 repair/restoration

Wouldn't it be nice if a B-I-G company like Nautel could acquire the schematic for these power supplies, so they COULD be repaired in the field. Probably would have made the repair job a whole lot easier and faster.

Bob M.
by kcbooboo
Thu Sep 28, 2017 6:41 am
Forum: FM Radio
Topic: V & H antenna radiated power
Replies: 3
Views: 313

Re: V & H antenna radiated power

Thanks for the replies. Sorry, I have to admit to being an old wife, or at least knowing one (and yes, I have stayed at a Holiday Inn more than once).

Bob M.
by kcbooboo
Wed Sep 27, 2017 1:18 pm
Forum: FM Radio
Topic: V & H antenna radiated power
Replies: 3
Views: 313

V & H antenna radiated power

Let's say a translator is licensed for 200 watts ERP into a directional yagi antenna with 6dB gain and this antenna is horizontally oriented, so TPO is about 50 watts (assume no loss in the coax). If they connect a second 6dB gain yagi through an appropriate power splitter and orient it vertically a...
by kcbooboo
Thu Jul 27, 2017 10:32 am
Forum: Ask the Engineers
Topic: A real head-scratcher
Replies: 7
Views: 929

Re: A real head-scratcher

There is joy in Mudville today. I purchased a Sencore CR70 CRT tester/rejuvenator for $65 shipped. It looks brand new. Came with all the adapters, including the "universal adapter" (a pod with EZ-clips at the end of five wires) and has the setup book. It passed the field tests. I subsequently bought...
by kcbooboo
Mon Jul 24, 2017 6:47 am
Forum: Everything else
Topic: Mounting stuff to old concrete block wall?
Replies: 18
Views: 1417

Re: Mounting stuff to old concrete block wall?

Since I mounted my dryer outlet on wood nailed to the poured concrete wall, here's another funny. When I bought my house in 1987, it came with a washer and dryer (still in service today and working great; the quality went in before the GE nameplate went on). There was a separate circuit run for the ...
by kcbooboo
Tue Jul 18, 2017 5:44 am
Forum: AM Radio
Topic: Antennas for Field Measurement
Replies: 7
Views: 839

Re: Antennas for Field Measurement

I believe Kevin was referring to the previous or original proof-of-performance measurements that had to be done when the station went on the air. Those are your reference, and the signal levels were surely made with an FIM. I have an FIM and a spectrum analyze and Scott loop antenna. There is a cali...
by kcbooboo
Mon Jul 17, 2017 4:34 am
Forum: Everything else
Topic: Mounting stuff to old concrete block wall?
Replies: 18
Views: 1417

Re: Mounting stuff to old concrete block wall?

I did a similar thing but to a poured concrete wall. Rather than fight with the drill bit moving around, I used a Hilti nail gun to anchor a piece of 3/4 inch plywood to the wall. I could then mount the dryer outlet to the plywood with ordinary wood screws. Another way that might work is to use your...
by kcbooboo
Wed Jul 05, 2017 1:11 pm
Forum: AM Radio
Topic: Collins 310W-1 Exciter Divider
Replies: 20
Views: 1833

Re: Collins 310W-1 Exciter Divider

Check the MC900/MC800 series on PDF pages 1260-1306: M902, M916, M926, M913, M920 are all RTL flip flops. This logic series accepts VCC=12V. There's probably nothing about the resistors and transistors inside that prevents it from operating with more or less voltage. You could almost build the IC ou...
by kcbooboo
Tue Jul 04, 2017 7:33 am
Forum: AM Radio
Topic: Collins 310W-1 Exciter Divider
Replies: 20
Views: 1833

Re: Collins 310W-1 Exciter Divider

The MC714G wasn't the right chip but it got me into the right section. At least you might find the proper semiconductor family (DTL, RTL, etc) and type of astable multivibrator (i.e. flip-flop) and can fashion something equivalent, even if on a piece of perf-board.

Bob M.
by kcbooboo
Tue Jul 04, 2017 5:03 am
Forum: AM Radio
Topic: Collins 310W-1 Exciter Divider
Replies: 20
Views: 1833

Re: Collins 310W-1 Exciter Divider

Thanks to the exciter PDF, I looked up the Collins part number. That got me to an MC714G. There's a datasheetarchive PDF file of a 1966 Motorola semiconductor book, 22MB. There are LOTS of 8-pin metal (G) flip-flops there, in many different logic families. They have the outputs listed as 1/0 rather ...
by kcbooboo
Fri Jun 30, 2017 5:15 am
Forum: AM Radio
Topic: Collins 310W-1 Exciter Divider
Replies: 20
Views: 1833

Re: Collins 310W-1 Exciter Divider

Could they possibly be "RTL" ICs, round domed epoxy, about 3/8 inch in diameter, made mainly by Fairchild in the late 60s, early 70s? Those preceded "TTL" ICs.

Bob M.
by kcbooboo
Sat May 27, 2017 5:23 am
Forum: Ask the Engineers
Topic: A real head-scratcher
Replies: 7
Views: 929

Re: A real head-scratcher

I concur with your analysis, but why does the grid voltage seem to go further negative (closer to -2100) when the intensity is turned CW, making the trace brighter? I thought noving the grid further negative would cut off the electron flow more, like it does in a triode or tetrode, reducing plate cu...