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May 2020 - Full size 80m End Fed Half Wave Antenna
In the previous article I said that the "small slither" of 80m that the 40m EFHW antenna gave me was OK because I wasn't a big fan of 80m. Well then came lockdown and I discovered that in the morning, 80m can be a friendly place - and I now wanted good coverage of all of 80m.
Relying on my ATU to match the whole band was not an efficient way to go. So could I fit the 80m version into my property? The answer was no - and then yes. By cheating.
I could gain some more room by dog-legging across the garden to the back fence. I could also gain a little more by replacing the short fishing pole with a monstrous 12 metre high Spiderbeam pole.
Now these are far from the humble fishing pole as it may be possible to get. The Spiderbeam range are seriously tough. I got mine from Nevada. Great service and it was delivered very quickly.
Even with the extra height I couldn't quite get the 133ft (or 40m) of wire in the property. So I ran a little bit along the back fence as shown below.
End Fed Half Wave antennas can be used on harmonically related bands that are multiples of the lowest. So now I have all of 80m. I also have 40/20/17/15/12/10.
Now given that the ferrite core and the wire only cost around £9 that's not bad. Factor in also the £99 Spiderbeam pole (because sadly I have no tall trees nearby), and it is still a cost effective antenna.
One of the tests recently made was using the reverse beacon network on 40m early in the morning around 6am. With 5 watts of CW I can reliably hit beacons on the east coast of the USA.
There are many links to EFHW antenna references in the previously described 40m EFHW article.
June 2020 update:
Just lately, Practical Wireless has run quite a few articles on the EFHW helping to promote an interest in this interesting antenna. In the July issue, Tim G5TM describes his experience with a half wave 20 metre antenna that comes pre-made from HyEndFed Antenna - a Dutch company.
In a similar way to my first EFHW, it is extended to work for the band below (in terms of frequency) to give extended service. The antenna which would normally provide 20m and 10m performance, has an additional 34uH inductor at the end and then a further short piece of wire added.
Like the 40m End Fed Half Wave, which does not give full performance over the whole 80m band, the 20m EFHW when extended - does not give you all of 40m - but something is a lot better than nothing - and in his article Tim describes how he adjusted his antenna to provide the SSB end of 40m.
He says that he achieved a 2:1 SWR coverage of the top end.
Three bands in only an 11.85m antenna is pretty impressive and should surely fit in many a small garden - especially (if through necessity), it was fashioned as an inverted "L".
The HyEndFed is marketed as a portable antenna but using the same 49:1 transformer as described previously, can be home made for very little money. Tim's well written article describes the impressive contacts that he made. Tim also uses the same 12m Spiderbeam pole that I own - which would allow the whole antenna to be raised as a vertical in the smallest of gardens.
Tim has also created a video presentation.