Search found 91 matches

by K4WRF
Sun Dec 29, 2013 7:34 pm
Forum: AM Radio
Topic: Oldest tower still standing
Replies: 34
Views: 5445

Re: Oldest tower still standing

OUTSTANDING!

Thanks for the GHB series!!!

wh
by K4WRF
Sun Dec 22, 2013 9:40 am
Forum: AM Radio
Topic: Oldest tower still standing
Replies: 34
Views: 5445

Re: Oldest tower still standing

Thanks for posting that plot Richard! We conducted that same NEC analysis thinking that the antenna was still slightly long only to discover Brown was pretty much right on. The before after vertical elevation plot compares IIRC. WSM was reduced by 70' about the same time that WCAU sent theirs to the...
by K4WRF
Sat Dec 21, 2013 10:12 pm
Forum: AM Radio
Topic: Oldest tower still standing
Replies: 34
Views: 5445

Re: Oldest tower still standing

hello everyone! Long time no type... good question about oldest standing AM tower. I don't know but the WSM-AM Blaw-Knox was topped out 81 yrs ago in September of 1932. The same crew that erected the WSM tower went to do the WLW BK, so WSM is slightly older by a few months. IDK about the WTIC BK's b...
by K4WRF
Sat Apr 07, 2012 4:13 pm
Forum: AM Radio
Topic: Crossed Field Antenna Test
Replies: 47
Views: 11675

Re: Crossed Field Antenna Test

Yeah, that big "whooshing" noise is not the hot wind blowing through the CF antenna, but the sound of James Clerk Maxwell spinning in his grave...

All the best!

K4WRF
by K4WRF
Tue Feb 28, 2012 9:48 pm
Forum: AM Radio
Topic: Really Basic Questions
Replies: 9
Views: 2252

Re: Really Basic Questions

In the case of detuning the top of an AM tower like the one shown here in this thread, typically what type of showing does the Commission require to prove that it is effective? Is this considered a sectionalized antenna? WOW! 243.8 degrees! Is that some kind of series fed tower electrical length rec...
by K4WRF
Thu Jan 05, 2012 9:07 pm
Forum: AM Radio
Topic: Impedance Bridge Testing
Replies: 23
Views: 5165

Re: Impedance Bridge Testing

I need to track down a copy of the Terman books, especially if you recommend them. I know the very basics on the care and feeding of AM's...I can keep them on the air, but rely on smarter people when things go real south. I'd like to have a much deeper understanding of them. Down load "Radio Antenn...
by K4WRF
Thu Jan 05, 2012 7:33 pm
Forum: AM Radio
Topic: Did someone need a dummy load?
Replies: 13
Views: 1866

Re: Did someone need a dummy load?

To measure that -44 -j47 did you have to hold the bridge up-side-down??? Heh, heh!!

I've *NEVER* seen one that flat!!!
by K4WRF
Tue Jan 03, 2012 10:29 pm
Forum: AM Radio
Topic: Gates 5 blowing FETs
Replies: 25
Views: 5911

Re: Gates 5 blowing FETs

Years ago, had this same issue with static discharges across the johnny balls. Sounded like rifle shots going off and it drove the magnaphase on the Conti crazy! very annoying but there were no MOSFET's in that thing. As part of much needed rusty guy wire replacements, we added 6' fiberglass insulat...
by K4WRF
Sat Jun 11, 2011 7:01 pm
Forum: AM Radio
Topic: SX 2.5-loosing valuable hair... help
Replies: 19
Views: 3200

Re: SX 2.5-loosing valuable hair... help

I recall an incident similar to this a number of years back but with a twist. The little SX-2.5 transmitter had gone through a frequency change years earlier in the field and just never would quite make power, everything else was perfect. Anyhow, there was one cap in the output network that was marg...
by K4WRF
Sat Jun 11, 2011 6:24 pm
Forum: AM Radio
Topic: WDAY Towers down
Replies: 14
Views: 2154

Re: WDAY Towers down

Here's a more recent photo of open frame line from a station in town: (duplicate photo removed - DS) It's no longer operational, but you can see the U-shaped brackets that are typical for this sort of transmission line. -- Jeff WSM has a run like this. Thought I had a picture but can't find it -- g...
by K4WRF
Tue May 03, 2011 4:20 pm
Forum: AM Radio
Topic: AIM Antenna Analyzer
Replies: 25
Views: 4537

Re: AIM Antenna Analyzer

As luck would have it I'm currently in a dialog with Array Solutions troubleshooting a serious bug in the PowerAIM 120 which sometimes causes inaccurate tower impedance readings on towers with negative (capacitive) reactance. Until this is resolved I would hold off on buying one if the primary reas...
by K4WRF
Wed Mar 30, 2011 9:52 pm
Forum: AM Radio
Topic: 70's CBS Audio Squash Boxes
Replies: 46
Views: 8909

Re: 70's CBS Audio Squash Boxes

For the time, they were the best, CBS Labs set the standard. Emil Torick Chief Scientist at CBS Labs fame only recently passed away. There were several time-constant mods that served to speed up the AGC in the 400's but later questioned as it increased distortion as a trade-off. Pretty much were tro...
by K4WRF
Sun Mar 13, 2011 3:43 pm
Forum: AM Radio
Topic: Energy-Onix AM Transmitters, Opinions?
Replies: 30
Views: 3904

Re: Energy-Onix AM Transmitters, Opinions?

Yes I do and NO!
by K4WRF
Tue Nov 09, 2010 7:13 pm
Forum: AM Radio
Topic: folded antenna or base insulated antenna
Replies: 24
Views: 4559

Re: folded antenna or base insulated antenna

I’ve seen several antennas over the years that employed a resistor to limit the RMS if the tower was too tall for the class of operation. Cases like where the AM was collocated with an FM and increased height was needed. Another couple instances where the height of the towers were taller necessary t...
by K4WRF
Sat Nov 06, 2010 2:35 pm
Forum: AM Radio
Topic: folded antenna or base insulated antenna
Replies: 24
Views: 4559

Re: folded antenna or base insulated antenna

Folded unipole type fed antennas have NO advantage in gain or performance over an insulated antenna of the same electrical length; none, zip, nada! For all the reasons Mr. Deep defined. Sometimes, these systems are synonymous with “snake oil”. That’s not an opinion, it’s the laws of physics. If your...