Quarter Wave -vs- 5/8ths Wave Vertical


Compare Red 5/8th -vs- Blue W/wave

Anyone who has mucked about with verticals will no doubt have worked out that a full-sized quarter-wave for the 40m band, more or less tunes up for 15m band.

It wasn’t until my entry in IOTA Contest this year that I convinced myself that they are not a cloudburner (as many people suggest) but compare favorably with a quarter-wave, even producing more gain by 2 dB at 10 degrees above the horizon.

OK, so 2 dB isn’t a huge gain, but hey – it’s free. Take it when you can!

Don’t forget, you can do the same for 10m band too by making an element 6.83m long and folding it back a further 1.11m (for 28.5 MHz). So you’ll need nearly 8m of wire. Don’t forget, that’s insulated wire!

4-Element Home-Brew Folded Dipole Yagi Dimensions

I’ve recently “made” a 4-element Yagi in software for my YouTube channel which should give a great match to 50 ohms.

If you’re into MMANA software modeling, here’s the file:

NOTE: This is a ZIP file because my Content Management System doesn’t like files ending in MMA. By all means have your Virus Scanner check this Zip file. There is only one file inside this ZIP. Just the MMANA file.

Quick SWR Calculator for Vertical and Dipole Ham Radio Antennas

Here’s a really simple way of double checking how to much to trim your antenna elements.

You only need to type in the numbers in the Cyan boxes.

Just type in where it is resonant right now – then type in where you would like it to be resonant and the spreadsheet will auto-calculate the trimming.

Film: How to use the SWR Adjustment calculator.

Adding 80m to DX Commander All Band Vertical (9-bands 80m through 6m)

Regulars will know about the DX Commanders very cool results which are now filtering through in real world successful contest scenarios.

My own issue is that I needed just one antenna that would deliver an all-band solution, certainly for the contest bands of 40m, 20m, 15m and 10m – but I also needed 80m in the mix too.

My holiday home has a very compact small garden so the option of putting up a dipole for 80m is out the question, but modelling suggested than exchanging the 30m element for an inverted L for 80m should work.

The 80m element therefore starts vertical, like all DX Commander elements and turns a sharp corner at 6.9m above ground and droops down for around 13m or so, hanging over a bush at around 3m off the ground. Probably not perfect but perfectly adequate to score 44 QSOs inside an hour on the Saturday eve of the IOTA contest. That score includes 16 different IOTA multipliers, certainly a wide spread around Europe.

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