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.
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
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. :)
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!
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 !
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
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
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.
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.
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
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
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
There is also the other way of looking at it... remember your training & for the classic 2 element yagi reflector is placed 0.15 wavelength back from the driven element, well 6m high on 40m is just that & the ground is conductive & acts as a reflector so your 6m high 7MHz dipole is actually a 2 element yagi pointing straight up for NVIS... the ground is your reflector. 6m is actually a good height to be at.
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.
Very true! Modelling has its uses and provides a guide. Sometimes it presents such a contrast to what we thought should happen that it prevents us wasting our time or, alternatively it encourages us to have a go. It’s all fun. 73
@@timg5tm941 I also respect old Pete's point of view. But it's a little different for him as he has a LOT of experience and knows instinctively a lot antennas that will stand a good chance. and ones that don't. The slightly younger/less experienced hams, have to do some sanity checking. Anyway, all part of the hobby. Keep up the good work!
I'm new to hf and just came upon this when researching antennas. Great and easy to understand presentation. I do have two questions. If I am only able to get the center part 15 to 20m up but the ends only go up to around 10, is that still better than every part of the dipole at 10 or will that sharp triangle hurt my angle of radiation? Also, with this very high off the ground set up that is optimized for 40m, does it hurt my 20m performance if I were to use the same dipole for it? Thanks
But....Tim....nearby objects are going to attenuate signal and effect that pattern. I do agree that where there is a will, there is a way....and low antenna is better than NO antenna! :)
First of all, i was really looking for someone to make such type of comparison, made situation pretty clear now...so thanx for that...i have a question about which im not very sure, you might be able to answer it....i have a 40m inv V dipole at the roof of my house, roof itself is around at the height of 20ft, and apex of the antenna is roughly 36ft.....can i safely say that the height of my dipole is 56 ft ?
@@Capt_Duffy it’s about a 1/4 wave from the roof at 40m. The roof will act as a secondary ground. Therefore in practical terms it won’t quite behave like an antenna at 56ft agl
is the height from tiles roof important for inverted V 40m dipole?Mine only 2' from the roof and about 10m from the ground. .SWR is high. Some suggested to have it at least 5' from the roof and the angle not too steep.
A look at a dipole flat against a inverted v might be a good comparison? Living in the NE of Scotland i find getting down to S England/ France or Netherlands, a horizontal ant east west works prety good any hight , but a high inverted v even at 60 feet i feal my sig south is lost somewhat ?
Well it’ll be a little more omni directional as a v but not much more given you’re almost a 1/2 wave above ground. Must be better broadside gain with the flat top?
