Re: LF: JA/EU

["Douglas D. Williams" <kb4oer@gmail.com>]

Yes, thanks Mal, my question was answered with some good information.

 

No, I have been monitoring the USA "Lowfer Band" (160-190 kHz) for the past couple of nights, with good success.

 

http://dl.dropbox.com/u/33457409/185300Hz.jpg

 

http://dl.dropbox.com/u/33457409/185300Hz%20WM%26SWI.jpg

 

http://dl.dropbox.com/u/33457409/186850Hz%20SJ.jpg

 

 

The FCC rules on transmitting in this band are severe. In a nutshell: 1 Watt into an antenna no more than 15 meters in length (including feedline). Most operators put the PA right at the base of the antenna. The captures you see above are at distances of up to 600(ish) miles.

 

A transatlantic reception of one of these beacons would be quite a feat. If anyone is interested in trying here is a link to the beacons and frequencies: http://www.lwca.org/sitepage/part15/index.htm

 

Note that the operators in the 137 kHz frequencies are running much higher power and are not subject to the same antenna restrictions and the "Lowfers" are.

 

I will probably turn my attention back to Europe this evening.

 

73,

Doug KB4OER

 

 

 

 

On Sat, Jan 7, 2012 at 9:33 AM, mal hamilton <g3kevmal@talktalk.net> wrote:

Hi Doug

I see another has replied to your query which is more or less correct but there are other variables depending on installation especially in radio amateur circles.

Did you observe any acty on 136.173 earlier on today. I was on TX for a short period before my sunrise 0630/0730 utc

73 es gl

de mal/g3kev

 

----- Original Message -----

From: Douglas D. Williams

To: rsgb_lf_group@blacksheep.org

Sent: Saturday, January 07, 2012 12:06 PM

Subject: Re: LF: JA/EU

Mal, I understand the relevance of what you are saying on HF, and even medium wave, but could you (or anyone who cares to) give me a brief explaination, or point me to a source of information, on LF propagation? I was under the (admittedly simplistic) understanding that, the lower one goes in frequency, the more the signal propagates via groundwave. I do know that almost all military installations transmitting in the VLF/LF bands use vertical antennas (very, very large ones with huge capacity hats). Do signals at 136 kHz experience "skip" from ionispheric reflection, similar to HF signals?

 

Doug KB4OER

On Sat, Jan 7, 2012 at 5:32 AM, mal hamilton <g3kevmal@talktalk.net> wrote:

LF

No sigs visible in JA from EU last nite at the peak time, around 2150 z. The JA grabber moved freq so not possible to check at 0740z the other peak time.

I think the antenna used for transmitting has some influence on the launch angle and distance covered and likewise the type of antenna at the receive site. ie low or high angle.

A vertical TX antenna system as high as possible would produce low angle signals, preferable for long haul DX, and low horizontal wires, loops etc would produce high angle, ideal for short ranges but not ideal for DX although the odd time high angle also does the trick. Large vertical loops fed correctly at the side  produce low angles but small vertical loops relative to frequency ie LF might be difficult to evaluate.

de g3kev