How I got 9 bands on the N9SAB 40-6 OCFD antenna (with no external tuner)

Discussion in 'Amateur Radio News' started by N2MAK, Sep 8, 2023.

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  1. N2MAK

    N2MAK XML Subscriber QRZ Page

    In this video, I continued my testing of the N9SAB 40-6m off-center-fed dipole on SSB and FT8 (to check for RFI issues). I was able to make contacts on 9 different bands with it (at 20-50W), some with and some without a tuner. I show the SWR across the bands on the NanoVNA, as well as my ICOM 7300 (SWR bar chart). If you're thinking about a multi-banded antenna like it, this should give you a good idea of what to expect (although it may vary based on different radios and setups).

    K9CTB, KS5KY, W4HM and 13 others like this.
  2. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    It's encouraging that you made contacts on all of those bands
    Sometimes an antenna with good SWR is nothing more than a dummy load, but you're actually getting out making contacts, great job.

    73 from,
    The K0UO " Rhombic Antenna Farm" miles of wire in the Air & On the AIR daily
    K9CTB, NU4R, KB5IAV and 4 others like this.
  3. N2MAK

    N2MAK XML Subscriber QRZ Page

    You bet! SWR is just one measure. Efficiency, radiation patterns and more are all factors for antenna performance.
    K9CTB, KB5IAV, K7GYB and 3 others like this.
  4. KI5UXW

    KI5UXW Ham Member QRZ Page

    Often when I'm looking for antenna designs that boast great SWR, I can't really find that much related material about people putting it on the air and what their volume and density of contacts are like. So, from one ham to another, thank you so much for making this video. :)
    K9CTB, KK4GCU, N2MAK and 2 others like this.
  5. AD4ZU

    AD4ZU Ham Member QRZ Page

    Click bait. Your station was inefficient. This antenna is not some amazing gift from God. You ran low power may have had some good prop and maybe just maybe things were so screwed up your rig couldn't even alert you about VSWR. And what did you run? FT8? I'm just guessing.
    NU4R and KR3DX like this.
  6. W9YW

    W9YW Premium Subscriber Volunteer Moderator QRZ Page

    Gosh, a guy has a good day and you insult his antenna, his video, and maybe his mode. Did you leave anything out?

    73 Tom W9YW
    KD6FOZ, KK7JPV, KR4EE and 33 others like this.
  7. K9NUD

    K9NUD Premium Subscriber QRZ Page

    Thanks for making some good YouTube content. Yes, a multi-band antenna will often do very well despite a mismatch. Obviously, a resonant antenna on those bands would be superior, but you made contacts, and that’s the whole point. You will likely catch some flak here for one thing or another, just ignore it. Focus on the people who find it helpful.

    For added satisfaction, try building your antennas. Check out for a ton of great information on OCFs and end-fed (a.k.a. extremely off-center fed) antennas. I followed his advice and ended up with a great antenna.
    KB5IAV, N2MAK, W9TNC and 5 others like this.
  8. KA0JW

    KA0JW Premium Subscriber QRZ Page

    Thanks for sharing the info on your antenna. Good video. Ignore the negative blah, blah, blah. Remember, it's only a hobby and to have fun doing it!
    73, Jeff
    K9CTB, KE4DIS, AF6SA and 5 others like this.
  9. KF4RMM

    KF4RMM Ham Member QRZ Page

    Great video! I just purchased the same antenna and I'm looking forward to putting it up.
    AF6SA and KI5UXW like this.
  10. N0VTY

    N0VTY Premium Subscriber QRZ Page

    I like to use a external "tuner extender" for those pesky hard to tune bands, A box of inductor coils on a switch, they do wonders for getting a tune and a signal out or in.
    N2MAK and KQ1V like this.
  11. W2JLD

    W2JLD Ham Member QRZ Page

    I watched the video and I was torn between thinking that this antenna was better than sliced bread and how one person account of an antenna useage in his particular situation...while others whom buy this better than sliced bread antenna might have different results.

    The best antenna out there is the one that gives you low swr and get you out there, I use a 66ft long ef antenna in a horseshoe shape pattern. I can tune up 6-40m by using a internal tuner i can just about the same swr as i do with the external tuner. Ive had nothing but excellent reports on it and my transmission are always a real s9 to a 10 over s9.

    So can i conclude that this is better than sliced bread. I use whatever gets me out there and has low swr
    As far as click bait...ummmm maybe so, but is not each and every vid out there some sort of click bait....

    In this hobby I have learned to just do whatever ever I do amateur radio the way you not let others define how you should be doing in this hobby.
    KE6MAK, N2MAK and KQ1V like this.
  12. KQ1V

    KQ1V Premium Subscriber QRZ Page

    @N2MAK I am pleased this antenna worked for you and you had fun making a ton 'o QSOs!

    I use a Chameleon NVIS EFW with a 49:1 transformer, 10 feet off of the deck, 8 foot ground rod, PolyPhaser, 27 feet of LMR217, and 70 feet of direct burial counterpoise. Naysayers tell me this is junk, yet my SWR is 1:1, and my log book is quite full. WAS at the new QTH last year on Phone/CW mix in a three week period; furthermore, I've worked over 100 DXCC entities OUS. What more can one ask for?

    You have to use what works for you, fits your budget, and the physical land/layout/restrictions.

    CU ON CW OM.
    Last edited: Sep 12, 2023
    K9CTB, K4XKF, NH6RF and 4 others like this.
  13. US7IGN

    US7IGN Ham Member QRZ Page

    Perhaps some people think that it is unfair when one radio could work on all bands, but one antenna could not. I think the guys who know how to model antennas in programs need to put more effort into developing an antenna that will have ideal SWR on all bands when folded :D
    N2MAK likes this.
  14. DO1FER

    DO1FER Ham Member QRZ Page

    The N9SAB 40-6 OCFD is a Windom-antenna. The antenna is nearly useable as a fullband.

    Now is the question why fullband QSOs were possibel in the video with an antenna for the 40 M up to 6 M band?

    The used Windom-Antenna is a Dipol with some blind portions in some parts of the frequency spectrum. But when a Dipol is not resonant, the radiation is still there. It will change partly into a kind of heating, went partly back to the transceiver and only the rest will get into the air at the blind portion of the antenna for the used frequency. So there is always a chance to make an antenna working at some frequencies where its not a good VSWR, but it still works with much limits.

    And an HF output signal with a VSWR of 3.0 up to 4.0 got only a refleted PEP of 25 % up to 36 %. And the rest of the signal will have a way outside. The next question is here now, in which Lamda the radiation pattern will change? When its to big, the whole thing will go phut chaotic.

    And when the Propagation is well, the rest of the emitted and modulated HF power will find its way out to the world. The only big thing is, that the used transceiver will not be thankful for the reflected power at the antenna output which will want to go back.
  15. K7GYB

    K7GYB XML Subscriber QRZ Page

    Great Job! Thank you for sharing your experience and always interesting to see how other low power operators derive and strategize their success! It's always fun to have a great day exceeding expectations! You have a great set-up!

    Ignore the haters. I operate QRP with a PackTenna random wire (72') and a tuner usually somewhere on a mountaintop here in the PNW. I'm approaching 1000 contacts since 2014 operating portable @ 5w or less with DX and local filling the logbook. So, I get the same drag from haters as well - especially when I'm able to get through pile-ups of QRO operators... that's the absolute BEST!

    Keep up the great work and hope to hear you on-air 73!!!
    K9CTB, KE4DIS, KB5IAV and 3 others like this.

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