[Elecraft] Fine tuning AF1

[Ron D'Eau Claire]

Mike, your description does not say how close that "miracle whip" is to the
KX1. Often they are mounted right on the radio. That puts the RF field as
close as possible to the KX1 and AF1. 

The second thing I'd do is connect a (roughly) 1/4 wavelength long wire to
the KX1 case to provide a lower impedance for RF at the rig. That will
provide a significant boost to your signal as well (in spite of the miracle
whip advertising). 

The first thing I'd do is to connect an extension wire to that whip antenna
and toss it in a tree, if that's at all possible. The miracle whip at 54
inches is an efficient radiator only 50 MHz and above, and then only with a
decent counterpoise. Note they say it will 'tune' over a broad range, not
that it is an efficient radiator over that range. No one has rewritten the
laws of physics, and they dictate that such an antenna is very, very
inefficient. What the miracle whip gets you is great convenience in many
situations.  

Adding length to it will improve the efficiency and move the RF field a bit
farther from the AF1. 

Finally, if a counterpoise or longer radiator are not options, you can try
putting bypass capacitors on the power and phones leads at the AF1. It's
likely the RF is being picked up by one of those leads rather than being
picked up by the AF1 circuits directly. Put a small value capacitor - 0.01
through 0.001 uf - across the power leads and audio leads on  the pc board
near the jacks. The larger value cap will be more effective at the lower
frequencies. That may reduce the RF getting into the circuit itself enough
to eliminate the issue. 

Ron AC7AC

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Mike Weir
Sent: Saturday, July 30, 2011 1:20 PM
To: elecraft at mailman.qth.net
Subject: [Elecraft] Fine tuning AF1


Using the AF1 along with my Elecraft KX1 and the Miracle whip antenna I
found the AF1 while transmitting with the KX1 at 1.2 watts was being
affected by the RF from the rig. When I used the auto tuner on the KX1 with
the AF1 turned on I would hear buzzing and clicking in my ear buds. Also
seemed when transmitting the AF1 was picking up RF as I could hear hash in
my ear buds along with the CW tone. At home I used my attic DX-EE antenna
along with the KX1 and AF1 did not have any issues. Any ideas for the
portable operations?? I have pictures of the setup on my blog if that may
help with ideas?
Mike
VE3WDM
http://ve3wdm.blogspot.com
 		 	   		  
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