[Elecraft] Strong recommendation: MFJ 18xx-series single-band whips for KX3, etc

[Edward R Cole]

I might argue semantics with you, Charlie but get that most folks 
think a "base loading coil" is for use with shortened antennas 
(showing capacitive reactance).

The 5/8 WL Larson VHF whip (cut for 2m) does load nice on low end of 
6m.  In fact my antenna is a Larson  with NMO base mounting coil to 
NMO magnet.  Its on my truck so not accessible to check actual model 
but LM sound's correct.  I bought several at work for high-band VHF 
mobiles and recall some had HW or HD marking.

I can't recall if I every tried 6m using the Maxrad version which we 
bought later in the 15 years on my last job.  So maybe only the 
Larson brand will work this way.  We only had a few MOT antennas as 
they were cheaper without MOT brand on them.  We also installed DB 
Products antennas (not NMO base).

You can also buy the Larson NMOQ which is a 1/4 WL whip with NMO base 
but no coil.  I don't recall what whip length is supplied but I 
recall buying some mobile whips that had 96 inch whips which you 
trimmed with bolt cutters to resonant length (cutting charts were 
pretty good for obtaining good SWR on a mobile).

73, Ed

---------
This only works for a 5/8  wave 2 M antenna where
the base inductor (It's NOT a * loading coil)
isn't tapped and grounded at one end.
In other words, if there is a single connection to
the antenna, this will work.
If there's a ground connection such that the
inductor is tapped up the coil it will not
function on 50 MHz.
The Larson LM series will work, but ones designed
for the Motorola (NMO) base will not.

73, Charlie k3ICH

* A 5/8 wave antenna presents roughly 50 Ohms
resistive and some level of capacitive (-J)
reactance.
In order to match this impedance, a series
inductor is required to cancel the capacitive
reactance,
So technically, it is not a "loading" which would
be designed to make up for the fact that an
antenna is too short for a ? wave resonance.
-------
OR buy a 5/8 wave base-loaded 2m mobile whip -
loads on 50-MHz very nicely.  That's an old trick
for dual-band 6m/2m use.  Try brands like Larsen
or Maxrad.

73, Ed - KL7UW



73, Ed - KL7UW
http://www.kl7uw.com
     "Kits made by KL7UW"
Dubus Mag business:
     dubususa at gmail.com