Bill's- HomeBrewed - 40 Meter TAK-tenna or TAK Antenna
So I've been reading about this Small Space antenna (Small Space HF Antenna) that is being sold as the TAK-Tenna. Really neat idea - Has a 30 inch boom and Spiral Coils on the ends. See a picture at http://www.taktenna.com/
Looks easy to build - Right ?
So I Built my version out of wood - Mine is very ugly as compared to the store bought one (See Pictures).
Materials and Tools • Parts:
1.) 3 - Wooden sections - 1 1/2 in X 1/2 in X 8 ft - Cost 92 Cents each - Home Depot
2.) 1 - 100' Spool of Steel Guide/fence Wire - Cost - $7 - Home Depot - The purchased version uses some type of "Special" patented wire, but this seemed fine. I tried Copper, but it was not stiff enough to make the Spiral Coils. Again from quick test it did not seem critical - From what I read larger gauge wire is better for improved band width.
3.) 1 - 25 foot RG8 coax with PL259 - Radio Shack - Close Out - $5
4.) 2 - Packages - Nuts/Bolts - $2 - Home Depot
5.) 2 - Aligator Clips - Free from my junk Box.
6.) Few Feet of Electrical Tape - Free from my junk Box.
Total Material Cost: $16.76
The commercial version uses PVC and tie wraps, which would have been much easier.
a.) Saw - I just used a simple hand saw.
b.) Drill with wood bits - I just used a simple hand electric drill.
c.) Flat Screw Driver and Rubber Malet.
d.) Wire Cutters.
e.) Gloves and Eye Protection.
For my version was about 4 hours - Drilling Lots of Holes and feeding the wire in to make the Spiral Coils was most of the work.
However - Test wise it isn't bad I got it tuned up on 40 meters at about 8 feet off the ground and it has an SWR 1:2 to 1:5 from 7.30 to 7.175 MHZ (Without a Transmatch). Also does ok on 15 meter - Tune up wise. Bad news the performance is not Great - Signal pick up is several S units below my Dipole, but it does work. From what I have read the Antenna has problems in that most of the performance is based on feedline radiation (See the links below).
Summary of Results:
I'm still testing and it was an interesting experiment. The Antenna fits into a small space 25 inch X 30 inch. Hey it works. If you have no space it might be worth $20 and a few hours of your time or If you aren't a Homebrewer Buy one. If you make your own one point - I needed more wire than the 468/7.2 MHZ = 65 Feet Total or 32.5 Feet per side - I had to add wire after the fact. So I would make it about 33.5 per side.
One more added item - Someone had a question about my dimensions:
Boom = 30 inches meaning Cross Pieces are about 30 inches a part.
Cross Pieces = 25 Inches Across or 12.5 Inches from center
Hole Spacing from Center, but this did not seem critical, but I used:
Total Turns = 10
a.) Put the antenna in the expected operating position (Mine was about 8 feet in the air).
b.) Conect the Coax via the Aligator Clips about 2 inches from the end of the smallest inner Spiral Coils.
c.) Measure SWR in the Center of the 40 Meter Band (SSB or CW) you intend to use most. If the SWR is too high move to Step d.
d.) Move the Aligator Clips/Coax out evenly about 2 inches on each Spiral Coil.
e.) Repeat Step c.
I was able to acheive acceptable SWR after about 3 cycles of adjustment without a Transmatch.
a.) Measure/Cut - (1) - 30 inch boom section.
b.) Measure/Cut (4) - Cross members - 25 inches sections.
c.) Measure/Notch @ about 12.5 Inches - I just cut with a hand saw then tapped out with a Flat Screw Driver and Rubber Malet.
d.) Drill holes in Cross members as noted above - Starting 3 inches from center then working out in 1 inch steps out to 12 inches. If you are careful you can save sometime by drilling two parts at a time.
e.) Here is the Hard part - Put the Notched Cross members together then start feeding the wire to create the Spiral Coils. I started from the biggest to the smallest. I would recommend Gloves and Eye Protection.
f.) Once the Spiral Coils are completed bolt them to the Boom.
g.) I then used the last section of wood for mast and bolted the Boom to this part.
80 Meter - Tak Tenna - Version Calculations:
I used Circumference of a Circle = 2*3.14* r ~ This is not perfect as this assumes we complete the full circle each time, but really don't. This should get you in the ball park. If you start from the center and work out - The 16th loop will not be a full loop. You might need make some adjustments, but it should be a good start.
Total - Inches: 835.24
Total - Feet: 69.60
Per Leg 60.78 (468/3.85MHZ) ~ 62.6 Feet per Leg assuming margined up 3%.
40 Meter - Tak Tenna - Version Calculations:
I used Circumference of a Circle = 2*3.14* r ~ This is not perfect as this assumes we complete the full circle each time, but really don't. This should get you in the ball park. If you start from the center and work out - The 12th loop will not be a full loop. You might need make some adjustments, but it should be a good start.
From Center: Amount of Wire:
Total (In): 452.16
Total (Ft): 37.68
Dipole: Half Wave Dipole: 468/7.2 = 65 Feet or 32.5 Feet per Side
Margined up by 3%: 33.5 Feet