Warning: Creating default object from empty value in /homepages/11/d132647312/htdocs/Amfone/mkportal/include/SMF/smf_out.php on line 47
Raspy AM carrier on 1920 kHz




 
The AM Forum
December 13, 2018, 03:51:39 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: Raspy AM carrier on 1920 kHz  (Read 6786 times)
0 Members and 1 Guest are viewing this topic.
wx3k
Member

Offline Offline

Posts: 152


Vintage Ham Gear Enthusiast


WWW
« on: April 03, 2013, 11:04:04 PM »

HELLO everyone....

I have been poking around 160 and I hear a raspy AM carrier on 1920 kHz. I live in Northeast PA. I hear this carrier most evenings. It is weak. There is QSB on this carrier. Sometimes it does come up in strength.

I have tried two different antennas and still hear this carrier. After extensive listening, I have identified it as the 3rd harmonic on an AM radio station on 640 kHz. After further research on the FCC website and listening to their stream off their website, I believe it is WHLO in Akron OH.

http://www.640whlo.com/main.html

Using a ICOM PRO 3 as a receiver.

Does anyone else hear this signal HuhHuhHuh?

 
Logged

Stephanie WX3K
Eico 720/722/730  HRO50T
"Thunder is good; Thunder is impressive but it is lightning that does the work" ...Mark Twain
wb8uhz
Guest
« Reply #1 on: April 04, 2013, 11:42:36 PM »



   Stephanie

Yes there is a harmonic from 640 Toronto on 1.920. The station is working on the problem. In Michigan where I'm located the signal can be above S9 at times and the audio is understandable.

73 Tim
WB8UHZ
Logged
Opcom
Patrick J. / KD5OEI
Contributing
Member
*
Offline Offline

Posts: 6971



WWW
« Reply #2 on: April 05, 2013, 08:13:36 PM »

Sooooo.... what does a 50KW low pass filter look like?
Logged

Radio Candelstein - Flagship Station of the NRK Radio Network.
wx3k
Member

Offline Offline

Posts: 152


Vintage Ham Gear Enthusiast


WWW
« Reply #3 on: April 05, 2013, 10:56:12 PM »

Really ?   Shocked

I suppose they carry similar programming.....I tried listening to 640 and all I heard were a bunch of stations all competing with each other.

How do you know they are working on the problem ? Did you call them ?



   Stephanie

Yes there is a harmonic from 640 Toronto on 1.920. The station is working on the problem. In Michigan where I'm located the signal can be above S9 at times and the audio is understandable.

73 Tim
WB8UHZ
Logged

Stephanie WX3K
Eico 720/722/730  HRO50T
"Thunder is good; Thunder is impressive but it is lightning that does the work" ...Mark Twain
wb8uhz
Guest
« Reply #4 on: April 06, 2013, 12:20:05 AM »




       They believe it is their ground system. And yes when asked I have assisted.
 I started hearing the station several months ago. First on an Orion,  then a Flex then an R8B. They want to fix it of course.
Logged
W7TFO
WTF-OVER in 7 land Dennis
Contributing
Member
*
Offline Offline

Posts: 2181


IN A TRIODE NO ONE CAN HEAR YOU SCREEN


WWW
« Reply #5 on: April 06, 2013, 01:30:14 AM »

Sooooo.... what does a 50KW low pass filter look like?

Every BC transmitter built in the last 50 years has very efficient harmonic suppression built in.

Two reasons: Regulations spelling out just what levels are allowed, and that energy going out the line costs $ to make.

A link to a treatise on the subject: http://www.hatdaw.com/papers/review_of_harmonic_suppression_practices.PDF

Canada pretty much follows the US in technical broadcast rules.

A BC antenna matching unit is typically a "tee" net, providing a match from 50Z to whatever the tower impedance is at the op freq.  That further 'losses' the harmonics, but at that point they are many dB down already.

The station in Toronto must have a really dicey antenna system to cause a 3rd harmonic of that magnitude, maybe something corroded causing re-radiation.

73DG
Logged

Just pacing the Farady cage...
K5UJ
Contributing
Member
*
Offline Offline

Posts: 2845



WWW
« Reply #6 on: April 06, 2013, 07:32:48 AM »

From what I've read, a T is a high pass network.  They seem to be pretty common tuning house networks for AM towers.   I got a Heathkit SA-2040 tuner from an estate a couple of years ago.  As soon as I found out it was a T network I sold it because of the high-pass property. 
Logged

"Not taking crap or giving it is a pretty good lifestyle."--Frank
KF1Z
Member

Offline Offline

Posts: 1788


Are FETs supposed to glow like that?


« Reply #7 on: April 06, 2013, 08:07:30 AM »

There are high-pass T's, and there are low-pass T's

If the series elements are capacitive, then it is a high-pass
If they are inductive, it is low pass.

AFAIK

Logged

W2VW
Contributing
Member
*
Offline Offline

Posts: 3489


WWW
« Reply #8 on: April 22, 2013, 04:11:57 PM »

Low pass has DC continuity from input port to output port.

High pass does not.
Logged
KM1H
Contributing
Member
*
Offline Offline

Posts: 3519



« Reply #9 on: April 22, 2013, 09:40:23 PM »

Quote
  Stephanie

Yes there is a harmonic from 640 Toronto on 1.920. The station is working on the problem. In Michigan where I'm located the signal can be above S9 at times and the audio is understandable.

73 Tim
WB8UHZ



Toronto has 50KW on 740 which is a flamethrower over a good part of the US with some great music.

Carl
Logged
Steve - K4HX
Administrator
Member

Offline Offline

Posts: 2428



« Reply #10 on: April 22, 2013, 09:46:25 PM »

What does that have to do with the subject? The frequency in question is 640 kHz.
Logged
KM1H
Contributing
Member
*
Offline Offline

Posts: 3519



« Reply #11 on: April 23, 2013, 09:11:14 PM »

I thought the 640 Toronto was in error but later tuned it in. Sorry if I disturbed you with a one line comment.............
Logged
Steve - K4HX
Administrator
Member

Offline Offline

Posts: 2428



« Reply #12 on: April 23, 2013, 10:33:06 PM »

Dammit Carl, you woke me up!  Grin
Logged
wb8uhz
Member

Offline Offline

Posts: 3


« Reply #13 on: October 08, 2018, 06:35:50 AM »

  The cause of the harmonic from 640 to 1920 was found to be from an antenna the 640 station was leasing space to on their tower. The problem has been corrected for a couple of years now.

73 Tim
WB8UHZ
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.087 seconds with 18 queries.