Ham Radio: 40 Metre Dipole In A Small Space

How I squeezed in a 40 metre dipole into a small garden!
Connect with my channel by subscribing and commenting

[KarlWitsman]

I used an antenna like this for years, indoors, and it worked great for SWL, receive-only. I modelled it after a similar antenna that we built inside a Radio Shack store to demo shortwave radios. Even inside the store, we could pick up stations from all over the world.

[richardowens]

One of the big eye-openers for me about how antennnas can be configured was when I opened up an old Grundig table top AM radio and discovered its internal antenna inside the rear cover - a simple concentrically wound coil of wire glued to the back on the inside of the cover. The electrical length was there, but not the physical length. But, the radio still had no problem receiving broadcast stations from all over the US. Of course, I have no idea how much loss such an antenna represents when you're fitting an antenna for AM frequencies inside a table top radio.

[jeffreywonser]

I'm a relatively new HAM, and how antennas work is still foreign to me. But, I'm starting down the rabbit hole, and this video was AMAZING for me! Thanks, Tim! 73's from K9WNZ!

[HamRadioDX]

Great explanation Tim. You’re videos are very informative as always. Keep up the good work 👍

[michaelmohr]

Thank you Tim for this video. Thank for the nice detail about this use of 450Ohm Ledderline !
vy 73 de DL1AQU Michael

[robinedminson]

Really informative. Might have a good look into this but with much wider folded section, 100-150mm.
MMANA, here I come 😊

[cubansplat]

Very good antenna design. I agree that the "real" test of antenna performance is on the air. It always amazes me the things some go through to squeeze one more db of gain out of an antenna. The difference will be unnoticed at the receiving end. Great job, Tim. 73 de K7RMJ Frank

[williamgrocott]

Great work Tim. Very insightful and I will try the same with a doublet and 300r ladder line. 73 de Will, M0LGW 👍🏻😊

[davemudb]

Like this Tim, I’m looking to do the same, but feed it with ladderline, linear loaded doublet. The length will be whatever i can cram in. keep up the good work. m0udb

[brian.]

well done Tim, Its always good to look at your antennas. many thanks, best of luck in the new year.

[maze]

Apologies Tim, I missed this one. Very interesting, via people like yourself YouTube has opened up a great mechanism for having a go! Regards Mike

[kitesurfphil]

I've made a scaled up version of this concept, using 300 Ohm slotted ribbon, for 80m to comply with the ERF rules in my 30m x 6m plot. When I noticed that as a fully folded dipole it was also the perfect length for a 60m antenna, I decided to feed it with 300 Ohm ribbon as a doublet. I was looking for a way if electrically shorting the gap for 60m and considered an 80m trao but this would have a shortening effect so I have left it alone. I'm having great fun on all bands from 80 to 10m and enjoying a lower noise level than I had on my big inverted L. I don't know how much difference it makes but the gap on my linear loaded antenna is at the top above the feed point. It was bang on resonance at the design frequency of 3.75 MHz and required no other adjustment. For the higher bands I'm using the trusty old SEM TranZmatch to load it up with good results.

[acestudioscouk-Ace-GACE]

Thanks Tim, this has been very useful. I need to make an antenna for a friend who is restricted to using his loft space and am considering using something like this as a starting point.

[chrismosquad]

Bravo, mate! Excellent video! Thank you for posting!

[Brenda-jfpe]

Keep making good videos, we are all still learning ! COVID prison gave me the study motivation to get the General. I’m working on the Extra just for the frequency’s we need more videos everyone needs more Elemering! JohnBoyUtah KJ7TBR 😎🇺🇸📡🎙

[DonDegidio]

Hi Tim,
I like the way you put the antennas to use after you model them. Was hearing you today in SE PA when you were mobile on 14209, but not enough for good copy. Stay safe. 73 WJ3U

[johnbaldwin]

Hi Tim
Thank you .I have ordered from Amazon in the uk and my daughter will post the ladder line to me...more expensive but at least i will have it...thank you for your comments...john

[richardowens]

Brilliant approach! Thank you so much for sharing this with us!

I do have a question, though:

You mentioned that the wider the spacing between the conductors, the shorter the overall length the antenna needs to be. So, is there a formula that allows us to calculate how long the linear loaded dipole needs to be, given the spacing between the conductors? For example, if I wanted to use sections of PVC pipe as spreaders to achieve a six inch spacing between the conductors, what would be the length of each leg?

Thanks, again, and 73!

[dxscotland]

Enjoyed this1 Tim and might try an inverted v for 80m! Thanks for the great videos 👍 73 Gm4zji Chris

[pcad]

Hmm.... Brings me to an idea. I have some I think 300 ohms ladderline laying around. I might use that at the end of my wire... If it get's a little warmer that is.