Search found 44 matches

by dd92251
Wed Apr 22, 2015 5:27 pm
Forum: AM Radio
Topic: Impedance Measurment Question
Replies: 62
Views: 8651

Re: Impedance Measurment Question

Hey Larry,

What town are you in ? f you're near Chicago...I might be able to help.


Dave Dybas
by dd92251
Mon Apr 20, 2015 5:10 am
Forum: AM Radio
Topic: AM Night Skywave Calculations
Replies: 7
Views: 1289

Re: AM Night Skywave Calculations

Deep Thought....Many thanks for uncovering my error ! I forgot the fact that Longitudes in the US are negative numbers. After correcting that mistake I was able to duplicate the FCC answer. :D

As always, I (and others) appreciate your help.

Best Wishes
Dave Dybas
by dd92251
Sat Apr 18, 2015 6:55 pm
Forum: AM Radio
Topic: AM Night Skywave Calculations
Replies: 7
Views: 1289

Re: AM Night Skywave Calculations

Hi Deep... I was hoping you'd be around :) In fact, I am duplicating the data in example of 73.185....using an Excel Spreadsheet to help with the calculations. I've converted all Degrees to Radians to use the Trig functions in Excel easily. Here is what I've got so far: TX Lat 40 00 00 Degrees = 0.6...
by dd92251
Sat Apr 18, 2015 3:36 am
Forum: AM Radio
Topic: Continental Power Pebble drive
Replies: 5
Views: 1319

Re: Continental Power Pebble drive

I believe I replaced the Fiber Optic cable and the Transducers as the new cable connectors wouldn't mate with the old transducers. It was a pretty easy process to replace the transducers.

Dave Dybas
by dd92251
Fri Apr 17, 2015 4:53 pm
Forum: AM Radio
Topic: AM Night Skywave Calculations
Replies: 7
Views: 1289

AM Night Skywave Calculations

Is anyone well versed on the FCC 73.190 AM Skywave Formulas ? The example that the FCC presents is a bit sparse in detail and I'm not able to duplicate their results. Maybe someone has experience with this ???


Thanks
Dave Dybas
by dd92251
Fri Apr 17, 2015 2:25 pm
Forum: AM Radio
Topic: Continental Power Pebble drive
Replies: 5
Views: 1319

Re: Continental Power Pebble drive

The 5 Kw Power Rock uses the same fiber optic coupling on it's PDM circuitry. I've had the fiber Optic cable go intermittent ...then bad on a rig a few years ago. I suggest you replace the fiber optic completely. The cable should still be available from Continental...and the replacement is a better ...
by dd92251
Tue Oct 21, 2014 12:58 pm
Forum: AM Radio
Topic: Gates 5 Solid State Output Power Drifts
Replies: 4
Views: 1113

Re: Gates 5 Solid State Output Power Drifts

I agree with Deep Thought....Check the Big Blue caps, remove one and shake it....if you hear some rattling noise or the caps feel like they're "empty" then they need changing. THese caps are notorious for causing problems in that series of Transmitter.
by dd92251
Tue Jun 03, 2014 10:37 am
Forum: AM Radio
Topic: Power Rock-13Khz oscillation
Replies: 18
Views: 3318

Re: Power Rock-13Khz oscillation

Hi All,

The 13Khz oscillation was traced to the SwitchMod board....replaced it and the problem went away. Likely there are some dried out caps or something, ....

Dave Dybas
by dd92251
Fri May 30, 2014 11:10 pm
Forum: AM Radio
Topic: Power Rock-13Khz oscillation
Replies: 18
Views: 3318

Re: Power Rock-13Khz oscillation

Deep Thought: The Mod Monitor is pegged on the positive modulation...and this occurs even without being connected to an audio processor. I've had several people mention the LV supply as a possible source of oscillation, so I will be looking at that this weekend. And I'll be putting a scope on the LE...
by dd92251
Thu May 29, 2014 9:47 am
Forum: AM Radio
Topic: Power Rock-13Khz oscillation
Replies: 18
Views: 3318

Power Rock-13Khz oscillation

Hi All, I have a Continental 5KW "Power Rock" that has a weird problem which has my little brain stumped. BTW: the rig is operating at 1KW right now due to this issue. The problem is there is a significant 13.5Khz (aprox) and 27Khz oscillation/spurs that are modulating the transmitter on either side...
by dd92251
Tue Oct 29, 2013 11:39 am
Forum: AM Radio
Topic: Gates-5 PA Diodes
Replies: 4
Views: 930

Re: Gates-5 PA Diodes

Fossil...sometimes I put glasses on top of my glasses :D ....to boost up the magnification....didn't help in this case. But Deep Thought came through ...and a few others have echoed his recommendation.

Gotta run now...to pick up my hearing aide battery ( just kidding )
by dd92251
Fri Aug 23, 2013 4:10 pm
Forum: AM Radio
Topic: harris gates one
Replies: 37
Views: 7903

Re: harris gates one

My first guess is that there is an impedance change in the antenna system. As Deep Thought mentioned these rigs are very sensitive to the load they're connected to. A) I'd start by checking the ATU for loose nuts & bolts and any loose connection. B) Next check the antenna feedline connection between...
by dd92251
Mon Aug 19, 2013 8:52 am
Forum: Help Wanted/Available
Topic: Contract AM Engineer needed- Kansas City, KS
Replies: 0
Views: 1384

Contract AM Engineer needed- Kansas City, KS

Contract AM Engineer needed to perform AM Station signal measurements in Kansas City, KS area. Must reside in the area, be experienced in operation of Potomac Instruments FIM-21/41 and AM signal measurement and be able to meet deadlines. For further details. Contact: Dave Dybas ddybas@ebiconsulting....
by dd92251
Sat Mar 30, 2013 4:30 pm
Forum: AM Radio
Topic: SBE's AMD specialty certification
Replies: 1
Views: 1025

Re: SBE's AMD specialty certification

I took the AMD test a month or so ago just to certify my skills. The test was pretty easy, but then again I've got several decades of AM Antenna experience behind me. I did pick up a copy of the SBE CertPreview for the exam and it was helpful for study. One thing that I didn't expect on the AMD Exam...