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Re: LF: TA CW?

To: <[email protected]>
Subject: Re: LF: TA CW?
From: "Alan Melia" <[email protected]>
Date: Wed, 25 Sep 2013 23:23:06 +0100
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Hi Bob that soundsa terrific location for Europe sloping away to the East, and it sounds like your ground is helpful too. It is interesting the well helps though not as much as hoped for......this is the sort of thing I mean by diminishing returns. One thought which may not be helpful is that with a "T" the highest voltage point is then of the top-load, So the maximum return current is collected underneathe the ends ( from a paper in  1926 about the Naun LF station in Germany)  that is the point where the earth mat is most effective. I am guessing from your description that the chicken wire covers that region.
 
As you were mentioning high RFvoltages...... This is perhaps where inductive to loading would help as it reduces the voltageat the feed point. The problem is it would not help with your 80m and 160m transmissions :-)) 
 
Just I quick thought....I assume from 80m etc use, the top runs N<>S ?? This would probably be the best for Europe on 73 because an E<>W sloping top would throw most of the signal at a higher angle in the direction of the top run....to Europe.
Interestingly I think you are geting reception to the south this may be skywave or a mixture. Skywave seems to predominate beyond 700km  say 500miles. I think you said the reports were from 300miles.
 
One of our problems was that we were alone in the UK for a lot of the time we had 73k and 300m would cover most of the active stations maybe 12 or 15 at most.
 
I am thinking that with a following wind on a good night you should be copied in Europe. QRSS is easy to generate but is not always the easiest to identify if it gets chopped up. Also most of the "artifacts" produced in the receiver and local to the receiver can look like weak QRSS  I always found a sheduled frequency move (very small) much easier to spot visually and it is why DFCW became so popular  (dots and dashes on different frequencies and no character gaps... only letter and word gaps ....of course with separation the dots and dashes can become the same length. ..shifts were often a few tenths of a Hz) It speeds up the transmission a bit.
 
Good Luck
Alan
G3NYK.  .
----- Original Message -----
From: Bob Raide
Sent: Wednesday, September 25, 2013 8:13 PM
Subject: RE: LF: TA CW?

Stefan;
The voltage is terrible!  I can draw a 2.5 inch flame off the ant input.  I am cramped for space to the west as I am only 20 feet from the neighbors line.  I am on 4 acre lot and room in all but that one direction.  More top loading would be great but also use this ant for 80 and 160 meters. 
I have seen the 700' Loran C tower up close and it uses the three top guys as top loading.  It used to wipe out all but the 500 kHz band here.  I could use 185 and did for awhile because 137 had terrible splatter from that signal.
You can go to google maps and get a real good shot of this place.  Last I looked the tower shows up and house with cars in driveway even.  If not I can take couple pix for you.  coordinates "NL 42-40-05 ; WL 77-04-28" 
You are probably using a much bigger ant than what I have here.  A couple hundred footer would sure help for 137/73-Bob
 

Date: Wed, 25 Sep 2013 15:21:20 +0200
From: [email protected]
To: [email protected]
Subject: Re: LF: TA CW?

Hi Bob,

Am 25.09.2013 03:01, schrieb Bob Raide:
[...]But only have a 90' high tower and at the top is the center feed point of my 75 meter double extended zepp.  I simply short the open wire line which runs almost vertically and fed it with allot of inductance in series! I assume the two 150' legs acts as top loading. Ground system is from my broadcast experience where for field intensity surveys 36" wide chicken wire was used with a 100' tower most often and a 250 transmitter.  Eight 50' chicken wire radials produced decent field on the midband channels [1000 kHz or so] to measure from.  Here I am using several 150' radials of chicken wire radials.  I hope to stretch some out to 300' but that's going to be about it at my location.

Can you post a link to some photos showing the tower and environment ?

Do you use deep earth rods additionally to the wire radials? Can you add even more capacitive load to the top of the tower, giving an umbrella antenna. 600 pF, as Alan sais, is nice but not much on 73 kHz and you seem to be voltage limited now (like me, sometimes :-) ).
Some images would be interesting for us i think.

73, Stefan/DK7FC
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