HF Log Periodic Problem

k4sb at avana.net k4sb at avana.net
Tue Oct 15 15:21:33 EDT 1996

Let's proceed on one assumption, that the impedence is indeed 105 ohms.
Put an electrical quarter wave of 72 ohm coax from the feed of the antenna
to your 52 ohm line. The quarter wave will act as an impedence transformer
and will step up the 52 to about 115 ohms. If your bridge then measures
about 1.1:1, then you've got it. However, if you get a reading of about
4.4:1, that should give you a good indication that the impedence is around
26 ohms.  You can solve that with a pair of 52 ohm lines using T

One precaution thought, DON'T start worshiping the SWR god. A good antenna
will still be a good antenna even if it has a 5:1 ( or greater ) SWR. The
problem then is to MATCH the impedence, not the coax.


Name: ed sleight
E-mail: k4sb at avana.net
Date: 10/15/96
Time: 2:21:33 PM

This message was sent by Chameleon 

>From broz at csn.net (John Brosnahan)  Tue Oct 15 20:26:19 1996
From: broz at csn.net (John Brosnahan) (John Brosnahan)
Date: Tue, 15 Oct 1996 13:26:19 -0600
Subject: SUMMARY:  Computer Cabinets
Message-ID: <199610151926.AA26368 at ns-1.csn.net>

Finally modified my computer power supply to include an AC
line filter (Corcomm) in place of the connector.  The interference
went away!  (Seems quiet even with the cover removed.)

Looks like the trend to mini-towers and their smaller power supplies
and the trend to cheapen up the manufacturing costs have eliminated
or minimized the required filtering on the AC line and the addition 
of commercial filters seems to solve the problem.

The only difficult part is widening the AC connector hole a bit to
make it accomodate the slightly wider filter using a nibbling tool and
a file, and (in one case) to bend over a component on the printed circuit
board to clear the case of the filter.

73  John

John Brosnahan  W0UN
24115 WCR 40
La Salle, CO 80645

"Radio Contesting IS a Contact Sport"

>From ken.silverman at CCMAIL.AirTouch.COM (Ken Silverman)  Tue Oct 15 21:44:15 1996
From: ken.silverman at CCMAIL.AirTouch.COM (Ken Silverman) (Ken Silverman)
Date: Tue, 15 Oct 96 12:44:15 PST
Subject: EU Layers
Message-ID: <9609158454.AA845409010 at CCMAIL.AIRTOUCH.COM>

     K1KP writes:
>Those appearing in 75-100 percent of US logs would be first layer; those 
>in 50-74% would
>be second layer, and so on. Maybe the percentages would need to be adjusted.
     I don't think this gets us where we want to go.  This kind of 
     percentage tells you the relative activity level of the station, but 
     doesn't allow you to classify the "level".
     What may be a better approach is to only look at ARRL DX logs (or 
     other logs where you send power levels) and determine the % of total 
     stations that fall into a predefined category.  For example:  By 
     looking at the % of 100w stations worked as compared to the total EU 
     stations worked, you now begin to get a better look at whether you 
     have hit that next "layer" of stations.  You would need to do this 
     over a few contests to get a better perspective.
     Sure people can lie about their power levels, but you have assume the  
     report sent is still indicative of their "level"   
     After all this, I don't quite know what we would get at...  working a 
     new "level" of stations likely says more about propagation on that day 
     than anything else.
     Kenny WM2C/6

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