Ham Radio: 40 Metre Dipole - Which Height?

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Published 2022-01-25
40m is a fun band, but if we have a dipole for 40m or any other centre fed horizontal antenna, just how critical is that extra 2 or 3 metres in height in terms of changing the characteristics of the antenna?
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All Comments (21)
  • @franc_ea6fs
    Excellent video, Tim: Simple, concise and clarifiying concepts. Good! EA6FS - Franc
  • @dandypoint
    Good info. I always say that on 160 and 80 meters a vertical is the way to go because most people can’t get a horizontal antenna high on those bands but 40 meters is different. It’s a transition band. If you can get 50 feet high then go horizontal. If you can get only 40 foot it almost does not matter. If you get a good ground system the vertical will be almost as good as the dipole but you lose close in coverage. I like half squares for verticals as you get some gain over a dipole and no radial system needed if you feed at a top corner. My 40 meter half square was equal to my 40 meter dipole at 40 feet. I kept the dipole because of simplicity and high angle performance. I now have a 40 meter dipole at 50 feet and it does quite well overall. In fact I have worked 100 countries in a contest over one weekend. The half square on 80 is absolutely a great antenna! 73 de N4DJ
  • @che59v
    Thanks, Tim, and just like that we learned why a low vertical antenna is the most practical and easy way to get those DX coming in. For NVIS a low-down dipole will do just fine.
  • Thanks so much, I'm new and trying to absorb as much as I can before setting up my first antenna. Also, thanks for mentioning the girls in the ham world. :)
  • @calthomas3
    Yay Team Tim. I appreciated your presentation (and associated skills) so much... kudos cheers and 73
  • valuable information, thank you for taking the time to model and demonstrate this behavior!
  • @davecarty6503
    Brilliant video Tim, so practical and exactly the kind of info the majority of us mere mortals in housing estates need to know.. getting antennas above the usual 20ft scaffold pole height without a tower or tall trees is certainly a challenge and usually involves fibreglass telescopic poles and of course they bend very easily once you add a dipole type antenna and look unsightly which then incurs the wrath of her indoors... doesn't stop us having a go all the same loll
  • Very inspiring.. I can just fit a 40m dipole straight in the garden albeit at 2m height and I am making contacts within 300miles very nicely this morning ON/PA/DD/MW. Thanks for the tip !
  • @darz3
    That was something Ive been wondering about, thanks Tim
  • @flipster7285
    I've lately been playing around with linked dipoles looking for an nvis antenna to use during local qrp competions. So after some calculations and considerations I built a LD for 40-10 that is only 3.5m high in the center. I set it up in my front garden for a test. My qth is in the bottom of a valley at 990-ish meters above sealevel. The tops of the mountains around me is at least 1700 masl with a small gap towards the North. I was pleasantly surprised! On 40m made a few contacts with locals about 500km south of me and others 300km west with no problem at all. The fantastic surprise I got was when listening around on 20m and deciding to answer an Italian station.....and I actually got a 57 sr! The signal most probably came right through the gap, but I was very happy. (Used a g90 so that was at 20w). Can't wait to get the antenna up on the mountain top during the next contest!
  • I want to mention my experience and that is i found higher than 2m above ground gave me a far better receive.Im working now at 5m above ground and the receive is far better in my situation
  • @travisscott3661
    Thank you sir! I have a 20/40m dipole about 7m high in the center and you hit it on the money with looking out at it and pondering of how much each step up could help haha
  • @markramsay6399
    Another excellent video Tim. I use modelling all the time in the day job (ionising radiation), but always try and get some real world measurements to "calibrate". As for HF, overall for DX use a 1/4 wave vertical. But even then, a EFHW at 8m still does the business sometimes! What I have learned so far is that one size fits all antenna just does not exist, at least not for my garden! So I have a DX Commander 1/4 wave, a EFHW and a magnetic loop. In a QSO I often switch between all three and it is really interesting to find that not all is as expected. I have a regular US station I listen to which is much louder on my EFHW, but when I have contacted them I am much louder when TX on my DXC. Mark, 2E0MSR
  • @garyh8315
    Grrat explanation. I made a dipole for 40m, approx 7 to 8m up, inverted. Managed to get a bit of DX, Costa Rica, Brazil and US. It is really good into Europe and for Inter G. Even down to 1w. 73
  • Good video Tim, thank-you. I'm fortunate in that I have lots of space but like most people, height is a problem. 10m or 30ft is about the limit for most people in the UK, I'm guessing. So it's reassuring to know that a lot can be done at lower heights.
  • @andyM7XTT
    Great video Tim,would like to see a video of yours about how to quieten down a vertical on 40m and 80m .take care
  • Nice one Tim, looking to get something for 40m. I watched the last one so would extra height/more horizontal help that. I can just get 50ft in a straight line ( half between the houses). Think I saw the video about modelling and open spaces.
  • @kellypaws
    Old Pete mate gives antenna modelling a good shoeing at every chance he gets. But if we all built EVERY antenna idea without a bit of pre-work, there'd be more wire than it took to cross the Atlantic.