Bill's- HomeBrewed Pan Cake - 40 Meter TAK-tenna

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KA6KBC, Jun 12, 2008.

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  1. KA6KBC

    KA6KBC Ham Member

    So I've been reading about this Small Space 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.

    Materials:

    Parts:

    • 3 - Wooden sections - 1 1/2 in X 1/2 in X 8 ft - Cost 92 Cents each - Home Depot

    • 1 - 100' Spool of Steel Guide/fence Wire - Cost - $7 - Home Depot

    • 1 - 25 foot RG8 coax with PL259 - Radio Shack - Close Out - $5

    • 2 Packages - Nuts/Bolts - $2 - Home Depot

    • Total Material Cost: $16.76

    The commercial version uses PVC and tie wraps, which would have been much easier.

    Fab Time 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. 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).

    http://lists.contesting.com/archives//html/Towertalk/2008-04/msg00339.html

    http://groups.google.ie/group/rec.radio.amateur.antenna/browse_thread/thread/167fb7a34305cf3e

    I'm still testing and will upload a picture of my ugly version at some point

    It was an interesting experiment and the Antenna fits into a small space 24 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.

    Any thoughts ?

    - Bill - KA6KBC - 73's

    Antenna - Pictures:

    http://www.myhamshack.com/HamShackPictureViewer/734/Pan-Cake-Antenna_3.aspx

    http://www.myhamshack.com/HamShackPictureViewer/732/Pan-Cake-Antenna_1.aspx
     
    Last edited: Jun 14, 2008
  2. KL7AJ

    KL7AJ Ham Member

    Any antenna is a thing of beauty. :)
     
  3. AG3Y

    AG3Y Ham Member

    Any antenna is better than NO antenna ! ! ! ;) :)
     
  4. WA2ZDY

    WA2ZDY Guest

    My brother (a ham nearly 50 years now) taught me this many years ago: a compromise in size is a compromise in performance. And you said it all - several S units down and a radiating feedline. Yeah, great antenna.

    Thanks for confirming what my brother and I assumed when we first saw the "commercial" version of that antenna (I'm being kind calling that) advertised. I'll stick with my attic mounted linear loaded dipole.
     
  5. KI6LQE

    KI6LQE Ham Member

    I tried building the 40-meter version using PVC pipe and 12ga. Copper wire. Took a little while to get the spacing right on the spirals but tuned pretty easy with a tuner. 1:5 -1 most of the phone band. Always fun to build stuff and see what it will do.

    I have made lots of contacts from California to South Carolina, Kansas, Texas, Florida, etc. running 100 watts out of the rig. I have not tested it for radiated power yet but will try in the near future.

    It is a lot less noisy that my dipoles and acts like a beam.

    I have it up at approx 20 feet. Here is a couple of pic’s

    Bruce
    KI6LQE
     
  6. K4DJQ

    K4DJQ Ham Member

    Hmmmm was just wondering what effects it would have on the antenna itself if you built a balun out of coax near the feed point.....Just wondering
    K4DJQ
     
  7. KA6KBC

    KA6KBC Ham Member

  8. N6YG

    N6YG Ham Member

    Hi Bruce;

    Is that palm tree in your back yard ??

    I bet a simple 40 meter wire vertical supported by that palm tree with two elevated radials run along the fence or roof would prove light years better then the pan cake antenna you are using now.
     
  9. KI6LQE

    KI6LQE Ham Member


    Thanks, It is a palm tree. Just out of the picture is an 80-foot redwood tree I have 3 dipoles hung off of. A G5RV up at approx. 65 as an inverted V and two sloped 20 meter dipoles, one north to south and one east to west.

    I built the “Pancake” to see how it would work but I agree the dipoles are much better.

    The G5RV inverted V works well on 40 and 20 and gets me out on 80 meters. I do favor the 20-meter dipoles for any work on 20.

    I was thinking about using the palm tree but it sways a lot in the wind and the redwood tree is pretty stable. I have bungi cords on the ends to keep the wire taught when the tree moves.

    I haven’t tried a vertical yet but I think I might give it a go

    Bruce
    KI6LQE
     
  10. KC4UMO

    KC4UMO Ham Member

    Bigger does has its advantages.


    Bill,
    Good thing is that it works and you built it yourself.
    Good job!.


    Now if you really want to see an ugly antenna look here:
    http://forums.qrz.com/showthread.php?t=165409

    Can not believe what some people will do
     
    Last edited: Jun 13, 2008
  11. KA6KBC

    KA6KBC Ham Member

    HomeBrew Ant ?

    Hey Buddy,

    Very nice work - I like it :)

    To Quote: kl7aj
    Any antenna is a thing of beauty :)

    - Bill - KA6KBC
     
  12. KC4UMO

    KC4UMO Ham Member

    Thanks Bill,
    Hope to have the coils covered today.
     
  13. W4INF

    W4INF Ham Member

    You still haven't responded to my PM, can you check your INBOX?

    Thx-
    Andrew
     
  14. KA6KBC

    KA6KBC Ham Member

    Bill's HomeBrewed Pan Cake Antenna

    See Pictures of my Version - Bill - KA6KBC
     
  15. KA5S

    KA5S Subscriber

    TANSTAAFL again

    If the ends of a dipole are bent into a spiral, you can get resonance at a notable reduction in size. But not THAT far; a resonant and reasonably efficient antenna that small would have an extremely narrow bandwidth, and the the Web site shows a TAK having more BW than a mobile antenna twice its size.

    Force 12 made a triband "spiral" loaded dipole some years ago, the ZR3. But this is that was an actual dipole.


    Cortland
    KA5S
     
    Last edited: Jun 14, 2008
  16. WB2WIK

    WB2WIK Premium Subscriber

    >If the ends of a dipole are bent into a spiral, you can get resonance at a notable reduction in size. But not THAT far; a resonant and reasonably efficient antenna that small would have an extremely narrow bandwidth, and the the Web site shows a TAK having more BW than a mobile antenna twice its size.

    Force 12 made a triband "spiral" loaded dipole some years ago, the ZR3. But this is an actual dipole.<

    ::If the TAK has more matching bandwidth than a mobile antenna twice its size, the only way that can be accomplished is by it having loss. I suspect it has plenty of that.
     
  17. KB9BVN

    KB9BVN Ham Member

    I have been thinking about buying a TAK-Tenna for use during campouts. I have read a ton of reviews from happy users and I know QRP ops that have gotten WAS and tons of contacts with 5w and the Tak-Tenna.

    Of course I wish it was cheaper....I'd have one already.
     
  18. K4SAV

    K4SAV Ham Member

    That's not the only way to get a wide bandwidth. The TAC by itself without the feedline has a bandwidth on 40 meters of about 10 KHz. Once you add a feedline of the right length you can get those wide bandwidth curves they claim on the TAC website. You can even get those double resonance points around 40 meters that the manual talks about. First you have to realize what comprises the antenna.

    It's similar to my 40 meter XM240 (2 elements on 40 meters). It's resonant on 160 meters with a fairly low SWR and it has a better signal to noise ratio on 160 than a low dipole. How? Well it isn't because of the length of the elements on the beam. It's because the choke on the beam doesn't look like a choke on 160 meters and that lets common mode currents flow on the feedline. Because the antenna is so short, those common mode currents are large. So the real antenna on 160 is the feedline and my tower which is closely coupled to the feedline.

    Jerry, K4SAV
     
  19. F8DRA

    F8DRA Ham Member

    The Tak antenna = A shortened dipole ?

    This antenna looks like a shortened dipole ! The two ends of the dipole are bent but certainly a little bit too much hi hi ! We normally call that " Capacitive Hat " but in this case i don't know how we could call this technology hi hi :D
    After reading several Antenna Books, i 'va always read that we could shorten a dipole maximum 25 % of its total lenght ! in other word, we can cut a dipole at 75% of its total lenght adding the 25% left using capacitive hats ....
    Below the 75% the dipole is getting less effective . In the case of the Tak Antenna the dipole seems to be shortened a little bit too much i think :D

    Sorry for my English :eek:

    Have a nice week end.

    F8DRA, Marc
     
  20. KA4DPO

    KA4DPO Ham Member

    Can't wait to see a shoot out between the TAK and Isotron. Should be interesting but my guess would be that the two will have similar performance.
     
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