An Easy Cushcraft D40 Mod Adding 30M

The Cushcraft D40 rotatable dipole is a great antenna – and its the same element they use on their 40M yagi. Because it uses coils and cap hats  instead of traps, it fairly efficient for a shortened antenna.

One way to really make this antenna sing is to add 30M. It can be done very easily by simply adding a wire below using standoff insulators of some sort – like these electric fence standoffs:

If the feed gets tricky as a “fan dipole”, then use 2 feeds. No big deal.

I can already see the bottom of the cycle starting at the end of 2018, and I fully anticipate that after 3Y0Z, my use of any high band antennas will be a waste of time. All of what I will be doing will be on 160 – 30M. Glorioso won’t be activated until at least a year after it is announced, and there is nothing in the rumor mill regarding that – so even if it were announced today, we would be very much at the bottom of the cycle. I fully expect that I would need to use a remote or someone elses super contest station.

Furthermore, there is a very good chance that I will be very seriously planning my retirement move before the peak of solar cycle 25, so, after 3Y0Z and 7 more QSOs on 160M I enter what I consider “very casual DXing” and the last throes of DXing from Orinda.

I love 40M, and when 30M is open and behaves like 40M, the same applies. I don’t even know if I will bother chasing anything on 160 or 80 after I make DXCC on 160 – my interest is starting to wane on it – this QTH is just a tough bugger and if I don’t get a surprise – like working EU on Top Band soon – my interest will fade for sure.

But I could be very happy just goofing around on 40 and 30M until I retire and move, and in my retirement I will probably also just goof around.

My definition of goofing around is use the radio like people watch TV, and build stuff and read “living history” books.

2 Comments on “An Easy Cushcraft D40 Mod Adding 30M

  1. Hi. Did you make this dipole mod and how did you do the feedpoint? How long is the wire that you hung below and is there any interaction or detuning of 40m? Thanks. Paul, W6IBu

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    • Its been a long time – but the design comes from an Optibeam rotatable dipole – where the 40M element has coils to shorten that band and a wire on standoffs hangs underneath for 30M. I don’t remember dimensions. I do know that its a back and forth cutting a larger wire down to size. I am sure it also ends up meaning both antennas are very narrow banded.

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