[Elecraft] KX1: requesting recommended wire antenna lengths advice

Sun Apr 19 21:33:32 EDT 2015

Sandy,

For the switchable balun I used the design of the Elecraft BL2 but used 
the binocular core of the K2 T4 transformer to get it into a smaller 
package.

I usually can find some near vertical  support post for the pole. At a 
campground, there are usually some vertical supports for a lightpole or 
a lantern hanging post.  There is always a picnic table that can offer 
some support for the pole.  Yes, I use bungy cords.
If you want to add something to your go-kit, add a 4 foot PVC pipe that 
is cut at a 30 degree angle on one end.  You can sink that into the soil 
by the angled end and use that for the pole support.  I also carry some 
mason line that can be used as guys for the pole if no real supports are 
available.  When deployed as an inverted VEE, the two radiator wires can 
also be used as guys, so the mason line is only needed for one (or 2 
additional guys).

In other words, do what you have to as dictated by the physical 
circumstances you are faced with.  A little ingenuity will go a long 
way, use what is available.  If you are planning a trip to the beach, a 
PVC pipe that can be driven into the sand to anchor the base of the pole 
and 3 or 4 tent pegs to secure the mason line guys will do the trick.  
In the forest of more primitive campgrounds, there are trees and shrubs 
to provide anchor points for the mast and any guy wires that are required.

If you have a camper, that can provide a solid fastening for the base of 
the pole, but if using a tent, you may have to use the picnic table or 
other supports in the campground.  Bungy cords will be a good addition 
to your portable gear.

OTOH, if you are backpacking, you are not going to have the telescoping 
pole, so a weighted bag to throw over a tree limb (or a rock with mason 
line around it) will have to serve as your antenna launching device.  It 
all depends on the circumstances you are faced with at the particular 
moment.  I have graduated from backpacking in my older age, so I can 
take more gear along with me on my portable outings.

73,
Don W3FPR

On 4/19/2015 8:58 PM, Sandy wrote:
> Don:
>
> I have done almost the same thing here on portable outings.  I use a 
> 33' MFJ telescopic fibreglass pole.  (What holds your up?
>  I use a 4 prong hand cultivator with a 3' shaft.  Hold pole on shaft 
> with a couple of bungee cords.  I'd like to scrounge the
> arrangement you use for the homebrewed 4:1/1:1 balun.)  Otherwise I 
> opt for the Buddipole at 9 feet as a dipole or a vertical
> with two drooping radial wires.   I have also used very frequently the 
> 33' single wire vertical and a Electraft T1 tuner.  (The T1
> is sometimes cranky to get to tune.)  Never thought about using the 
> dual 22 guage teflon wire as a twisted pair balanced line!
> Just using a vertical wire I frequently use a single radial, the 
> length varying depending on the band.
>
> ALWAYS a problem is 80-30 meters.  Usually done with a pair of 
> drooping radials and a vertical radiator consisting of 4 "Antenna arms"
> (88" total) and a single 9.5 foot telescopic whip above the antenna 
> arms.  One Buddipole loading coil at base of vertical /antenna arms
> combination tuned for resonance.  In many instances the trees, etc. 
> for Inverted V dipoles 2' fibreglass "driveway marker rods" 2 feet long.
> I will try the teflon twisted pair feeder.  Never thought of that. I 
> have some old 75 ohm receiving twin lead, good for that sort of thing,
> but it is too oxidized to consider it reliable in the field!
>
> I try to avoid the loading coils in the dipoles except for the higher 
> bands.  Although the Buddipole works well as a dipole at 9 feet up
> sometimes the vertical whip is better on 20 meters.  As I said, ALWAYS 
> a problem at 80-30 meters to play with verticals with whips.
>
> Good tips.  All of that can be a big guess without the trusty MFJ 
> analyzer!
>
> 73,
>
> Sandy Blaize W5TVW
>
>
> On 4/19/2015 6:58 PM, Don Wilhelm wrote:
>> My best field antenna consists of a 32 ft. heavy duty push-up 
>> telescoping fiberglass pole which supports an inverted vee with 
>> radiator legs 22 feet long (of #22 teflon insulated wire).  The 
>> feeder is twisted pair #22 teflon insulated wire (parallel feedline) 
>> 25 feet long.
>> That feedline terminates into a balun which is switchable between a 
>> 1:1 and a 4:1 ratio (a smaller homebrew version of the Elecraft 
>> BL2).  I carry a 25 foot length of coax to connect from the balun to 
>> the transceiver.
>> That antenna loads and works well for 40 through 10 meters - I switch 
>> the balun from the 1:1 to the 4:1 position depending on the band in 
>> use and the best match.
>>
>> I also carry two additional lengths of #22 teflon insulated wire 
>> which I clip onto the ends of the radiator to extend the length if I 
>> want to operate on 80 meters.
>>
>> That is my portable antenna, and it works well for me.  I prefer 
>> balanced antennas when I can use them.  It is not 'backpack' eligible 
>> because of the 32 foot pole, but then I am not doing any backpacking 
>> these days.
>>
>> I can put my antenna up in several configurations.  If I have a 
>> support for one end, I can set the antenna up as a dipole.  If I only 
>> have the fiberglass pole, I support the center of the dipole at the 
>> top of the pole and use it as an inverted VEE (the most desirable and 
>> common configuration).  In cases where I do not have much horizontal 
>> real estate to work with, I set it up as a vertical - the end of one 
>> radiator wire is tied to the pole and the other radiator wire is used 
>> as a 'radial' - 10 feet of it comes down the pole (the feedline is 10 
>> feet above the ground), and the remainder of the 'radial' is hung on 
>> nearby shrubs and bushes in the best manner possible.
>> So, three antennas in one - depending on the terrain and other 
>> available supports.
>>
>> 73,
>> Don W3FPR
>>
>>
>> On 4/19/2015 7:31 PM, J wrote:
>>> I'd also like to try a doublet of 60 to 88 feet; fed with a parallel
>>> feedline of made the same "stealth" wire as the antenna (no heavy 
>>> ladder
>>> lines).  The doublet would be more cumbersome (requiring one central 
>>> support
>>> or else supports at each end).  The antenna plus feeder length would be
>>> chosen to provide a relatively tame feedpoint impedance and 
>>> reactance on the
>>> three bands; 40/30/20M.
>>>
>>> More research is needed on end- and center-fed (no coax) wire antenna
>>> lengths for the KX1   (and the KX3)
>>>
>>>
>>
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