Re: [Elecraft] 40-80m choices antenna for KX3

[Walter Underwood]

The Hy-Power trap/fan antenna for 80/40/20 is a very clever design. A full 
length 40 m dipole, then a loaded 80 m dipole where the center portion is cut 
for 20 m. The loading coils act as traps. The loaded dipole is just about the 
same length as the 40 m dipole, 70 feet.

Check out the 3B2080SFAN on this page. 
https://www.hypowerantenna.com/products/fan-dipole 


I had to take mine down a few years ago when our walnut tree died. I just 
figured out how to rig it diagonally across our roof after a few frustrating 
years with a home-brew non-resonant vertical.

Here are a couple of photos of the previous installation. That is a Balun 
Designs QRP balun at the feed point. That dropped noise by about 6 dB.

https://www.flickr.com/photos/walter_underwood/5907110302/in/album-72157626885239329/
 

https://www.flickr.com/photos/walter_underwood/5854609078/in/album-72157626885239329/
 


wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/  (my blog)

> On Nov 2, 2022, at 9:18 PM, Jim Brown  > wrote:
> 
> On 11/2/2022 5:38 PM, Karl W Hubbard via Elecraft wrote:
>> How to rig and which antennas for my KX3 (has ATU) given the following  
>> layout andlimitations:
> 
> When I moved into a new QTH 16 years ago, I made a scaled drawing that 
> included my house, shack in detached garage-apartment, and available supports 
> (in my case, tall redwoods), and in relationship to North. That took a while.
> 
> Antennas have two important functions -- transmit, and receive, and every 
> antenna has some sort of directivity. Many antennas transmit well enough, but 
> pick up so much noise from our neighborhood that we can't hear most of the 
> stations calling us, and if we can't hear 'em, we can't work 'em!
> 
> The most noise resistant antennas are horizontal dipoles that are resonant on 
> the bands where we want to use them, are fed with coax, and have an effective 
> common mode choke at the feedpoint. SO -- study your own possible skyhooks 
> (trees, buildings, a guyed mast you might add to a building) and figure out 
> which combinations might support dipoles. Dipoles are VERY easy to build -- 
> you need plain ordinary wire (I mostly use single-conductor house wire), a 
> center insulator, end insulators, and rope to rig it.
> 
> OCF dipoles transmit OK, but they are terrible for receive noise, and there's 
> no good way to kill that noise. Ditto for end-fed wires. We're moving into a 
> solar maxima, so the higher bands (40-10M) are going to be much better than 
> the lower ones (160-60M).
> 
> It's also possible to build multi-wire fan dipoles that cover multiple bands. 
> Take a look at what I did in Chicago with a fan for 20-15-10. Here in 
> California, I've used 2-wire fans for 80 and 40.
> 
> http://k9yc.com/LimitedSpaceAntennas.pdf 
> 
> 
> And it's possible to build 2-band dipoles using loading coils, and 3-band 
> dipoles using traps. Both types are shorter than a simple half-wave dipole 
> for the lowest frequency. In Chicago, I had an 80/40 with a loading coil that 
> was about 100 ft long, that fit between a TV mast on the front of my house 
> and another on the garage at the back of my lot, and it worked pretty well in 
> some directions on 30 and 17M. HyPower Antenna Company (a Pennsylvania ham in 
> his basement, advertising in QST) sold it.
> 
> 73, Jim K9YC
> 
> 
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Re: [Elecraft] 40-80m choices antenna for KX3

[Jim Brown]

On 11/2/2022 5:38 PM, Karl W Hubbard via Elecraft wrote:

How to rig and which antennas for my KX3 (has ATU) given the following  layout 
andlimitations:


When I moved into a new QTH 16 years ago, I made a scaled drawing that 
included my house, shack in detached garage-apartment, and available 
supports (in my case, tall redwoods), and in relationship to North. That 
took a while.


Antennas have two important functions -- transmit, and receive, and 
every antenna has some sort of directivity. Many antennas transmit well 
enough, but pick up so much noise from our neighborhood that we can't 
hear most of the stations calling us, and if we can't hear 'em, we can't 
work 'em!


The most noise resistant antennas are horizontal dipoles that are 
resonant on the bands where we want to use them, are fed with coax, and 
have an effective common mode choke at the feedpoint. SO -- study your 
own possible skyhooks (trees, buildings, a guyed mast you might add to a 
building) and figure out which combinations might support dipoles. 
Dipoles are VERY easy to build -- you need plain ordinary wire (I mostly 
use single-conductor house wire), a center insulator, end insulators, 
and rope to rig it.


OCF dipoles transmit OK, but they are terrible for receive noise, and 
there's no good way to kill that noise. Ditto for end-fed wires. We're 
moving into a solar maxima, so the higher bands (40-10M) are going to be 
much better than the lower ones (160-60M).


It's also possible to build multi-wire fan dipoles that cover multiple 
bands. Take a look at what I did in Chicago with a fan for 20-15-10. 
Here in California, I've used 2-wire fans for 80 and 40.


http://k9yc.com/LimitedSpaceAntennas.pdf

And it's possible to build 2-band dipoles using loading coils, and 
3-band dipoles using traps. Both types are shorter than a simple 
half-wave dipole for the lowest frequency. In Chicago, I had an 80/40 
with a loading coil that was about 100 ft long, that fit between a TV 
mast on the front of my house and another on the garage at the back of 
my lot, and it worked pretty well in some directions on 30 and 17M. 
HyPower Antenna Company (a Pennsylvania ham in his basement, advertising 
in QST) sold it.


73, Jim K9YC


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[Elecraft] 40-80m choices antenna for KX3

[Karl W Hubbard via Elecraft]

I have been inactive for three years with  KX3,  KPA100and  PX3. Retired now. 
Living at myoffice until it gets sold. Trying to get back into things, 
especially 40 and 80meters SSB and cheating on CW using  PX3 
typeencoding/decoding if possible.  

Question: How to rig and which antennas for my KX3 (has ATU) given the 
following  layout andlimitations:

Far left end of parking lot has 25 foot tree. From therealong the back end 90 
feet to the right back end (the corner), there is a 50 fttree. From there, at 
right angle, it is 70 feet to my office with the roofabout the usual 10 feet 
where the coax feed line could enter into my office. Innorth east  NC 40 miles 
from Outer Bankscoast, essentially at sea level.

Plan on using 50 ohm USA Flex low-loss coax. Would ahorizontal “L” be 
functional, with the highest point at the right corner treeat the right angle 
of the “L” and the coax dropping vertically and then runningto my office?

Here’s what’s in my collection. (I’m not buying any morestuff until I relocate)

Parz 20/40 End Fed (would not capture 80m) nor would my AlexLoop. 

Buckmaster 7 band OCF  75-80m to 6 m, 300 W

EmComm III  80-6 m100W

Buddipole Vertical. I have the TRSB, extension arms, longwhips, shock cord 18ft 
mast  etc but reallydon’t want to rig it in the center of the parking lot as 
occasionally cars cutthrough. (I’m on a corner lot.)

So any ideas? Start from scratch and get some 12 gaugebraided wire,  a balun  
or un-un etc? I still have some old 20 and 40meter dipoles with the insulated  
12 gaugewires I experimented with years ago. 

Although I’d like to just run an end fed from the taller treein the right 
corner to the building, I really don’t think I have enoughdistance from that 
tree to the office for 80m, I think. 

Any suggestions? Thanks in advance for any suggestions.

73’s,

Karl “Hubbs” AF5LQ

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