Search found 72 matches

by mbrockm
Thu Sep 21, 2017 8:48 am
Forum: STL Engineering
Topic: Backup STL link
Replies: 8
Views: 559

Re: Backup STL link

For that distance, I would think a 900 mhz data link on a couple of yagis would do the trick, even through some trees. Ubiquiti, or Mikrotik, and the like. I'm using Mikrotik radios diplexed into one of my STL paths, and it works great across the Sacramento metro out to south of rancho cordova. dav...
by mbrockm
Fri Aug 04, 2017 8:33 am
Forum: STL Engineering
Topic: Backup STL link
Replies: 8
Views: 559

Re: Backup STL link

If you're just looking for a backup positive way to shut off the transmitter, why not use the squelch contacts on the STL receiver and connect it to one of the transmitter external interlock connections? Shut down the STL transmitter and off goes your broadcast transmitter. A good idea for a failsa...
by mbrockm
Fri Aug 04, 2017 8:30 am
Forum: STL Engineering
Topic: Backup STL link
Replies: 8
Views: 559

Re: Backup STL link

jammerdave wrote:
Thu Aug 03, 2017 8:44 am
I'm using Mikrotik radios diplexed into one of my STL paths, and it works great across the Sacramento metro out to south of rancho cordova.
What model of MIkrotik are using? What did they cost?
by mbrockm
Thu Aug 03, 2017 8:07 am
Forum: STL Engineering
Topic: Backup STL link
Replies: 8
Views: 559

Backup STL link

Looking for idea on a "cheap" backup link between our Studios and AM site for site control. Using Burk Arc SL plus. I am using a pair of 950 Marti STL 10 for audio. Transmitter control is thru DSL. We have had several DSL outages in recent months. The distance is about a mile and a half. Line of sit...
by mbrockm
Mon Jul 10, 2017 5:29 pm
Forum: AM Radio
Topic: Daytime Impedance high?
Replies: 26
Views: 1643

Re: Daytime Impedance high?

I got my replacement coil from Kintronics today. The old coil was a 6" outside diameter coil with 23 turns. The replacement from Kintronics is only a 5" outside diameter coil with 22 turns. The windings on both are 1" wide flat copper. Circuit wise the coil is across the common point and ground. The...
by mbrockm
Mon Jul 03, 2017 12:15 pm
Forum: AM Radio
Topic: Collins 310W-1 Exciter Divider
Replies: 20
Views: 1248

Re: Collins 310W-1 Exciter Divider

No luck finding any spares here for sn1147. Also looked thru my old digital logic books for the SN1147.Struck out. I am attaching a copy of the 310W instructions manual which has circuit descriptions if it helps. I think you are right that it some kind of jk flip flop. Problem is the 28 volt supply....
by mbrockm
Fri Jun 30, 2017 12:35 pm
Forum: AM Radio
Topic: Collins 310W-1 Exciter Divider
Replies: 20
Views: 1248

Re: Collins 310W-1 Exciter Divider

We have an 310w-1 exciter. My manual also indicates a SN1147 for z1 and z2. I will look and see if by chance we have any on the shelf. Also will check my old cross reference guides. You might try seeing if you can find a cross reference to for SN1147.
by mbrockm
Wed Jun 28, 2017 9:23 pm
Forum: AM Radio
Topic: Daytime Impedance high?
Replies: 26
Views: 1643

Re: Daytime Impedance high?

We will see what daylight shows tomorrow at KMA sites
by mbrockm
Wed Jun 28, 2017 12:22 pm
Forum: FM Radio
Topic: Nautel NV10LT
Replies: 21
Views: 2047

Re: Nautel NV10LT

We have had an NV30 for about 7 years. Had a problem at first blowing PA module 7. After we installed a shorting stub next to the output that problem ended. Now we just go thru a power supply or two a year. Fixed a couple by cleaning the bug juice out of the fan. If anyone (davek) has any tips on re...
by mbrockm
Wed Jun 21, 2017 10:36 am
Forum: AM Radio
Topic: Daytime Impedance high?
Replies: 26
Views: 1643

Re: Daytime Impedance high?

I did looked at surplus sales. Be nice if I could find some spare wipers. I have 7 of these variable coils in my system. Probably not if, more the when they will fail.
by mbrockm
Tue Jun 20, 2017 1:57 pm
Forum: AM Radio
Topic: Daytime Impedance high?
Replies: 26
Views: 1643

Re: Daytime Impedance high?

Since the recent the recent rain the base current meter is exactly where I calculate it should be. Go figure. However new problem. One of the adjustable coils in the phasor has failed. The wiper contacts are completely gone. The phasor and guts were originally made by Harris. I have a quote from kin...
by mbrockm
Thu Jun 15, 2017 10:44 am
Forum: AM Radio
Topic: Daytime Impedance high?
Replies: 26
Views: 1643

Re: Daytime Impedance high?

A few development in the problem. I used a cold bridge to measure center tower impedance. Right at license value. It appears the delta toroid meter is being affected by something. I have heard that tall am towers do not always work with delta meters. The recently calibrated meter and transformer is ...
by mbrockm
Wed Jun 14, 2017 8:26 am
Forum: AM Radio
Topic: Chain link fence
Replies: 5
Views: 446

Re: Chain link fence

Tower 480' used for Non DA and DA on 960. Fence is 25 feet from tower. Looked into vinyl which would look good but about 2K more in price then chain link. As most of us are, I am looking for least expensive.
by mbrockm
Tue Jun 13, 2017 9:12 am
Forum: AM Radio
Topic: Chain link fence
Replies: 5
Views: 446

Chain link fence

We have always had wooden fences around our towers. Need to replace around our center fence. Thinking of going to chain link, less expensive and durable. Question I have is how often do I need to ground the fence. I was thinking the 4 corners and 4 sides would be adequate.
by mbrockm
Sat May 20, 2017 6:04 pm
Forum: Ask the Engineers
Topic: Offical AMC 8 Transition Thread (was Sat. AMC-8)
Replies: 149
Views: 7973

Re: Offical AMC 8 Transition Thread (was Sat. AMC-8)

We borrowed a sat meter which would tell us which bird we were on. Then marked the various positions on the pole. Once we found some some nearby birds it was fairly simple to find the one we wanted. Highly recommend borrowing one.