Many because of Alan (W2AEW) for the next visitor put up:
by Alan (W2AEW)
One among my favourite antennas to make use of for POTA activations is a 40m EFHW wire. When correctly tuned and deployed, it may be used on 40, 20, 15 and 10m with out using a tuner (though, I actually don’t thoughts utilizing a tuner after I must). Most of my activations are on 40 and 20m, so these bands are coated simply. It may be used efficiently as a sloper, an inverted vee, or a mixture of those (regardless of the bushes or help constructions enable). It’s environment friendly, cheap to construct, light-weight and efficient.
There are a number of downsides to this antenna. The primary is that it’s roughly 68 toes (nearly 21 meters) lengthy. That’s a whole lot of wire to get within the air. Some POTA websites simply don’t have that a lot room or help constructions to successfully use this antenna. One other draw back is that it doesn’t naturally help operation on the 30m band, one other favourite of mine.
A number of weeks in the past, I watched a video from my good friend Vince VE6LK entitled: “Uncover the key components to construct a trapped EFHW antenna”. This piqued my curiosity…
The video introduces a design for a 40/30/20m trapped EFHW. The truth that it covers the three bands I exploit probably the most, and could be shorter than my trusty full-sized 40m, and provides me 30m in addition, obtained me excited to study extra.
Vince used a pair of traps (30m and 20m) which are provided in equipment kind by Tim Sherry, N7KOM. Here’s a hyperlink to equipment on Etsy.
These are solely to be used at QRP energy ranges – excellent for my utility. I positioned my order instantly after watching the video. The construct directions are very detailed, together with the way to tune the traps, which is crucial in getting the antenna to work.
He additionally used a 49:1 UNUN from SparkPlugGear. I’ve had one among these in my POTA equipment for some time, however solely used it sometimes. This was one other good purpose to proceed with this antenna construct.
In fact, you would additionally use the QRP UNUN equipment from KM4CFT that I made a video about earlier this 12 months.
I created a video that confirmed the way to assemble and tune the traps. Tuning generally is a little difficult, after which stabilizing the turns/spacing to protect the tuning is crucial – not exhausting, simply takes a little bit of persistence.
With the traps constructed and tuned, the following step could be to construct and tune the antenna itself.
I used to be capable of finding the time this weekend to just do that, and make a video of the method.
Particulars of the ensuing wire phase lengths are within the video. You will need to notice that if you happen to resolve to construct this antenna, your wire lengths will probably range from mine. A number of elements will impact the ensuing lengths (particulars of the UNUN used, the lure development, and so on.). My video goes by way of the method I used to construct, tune and check the antenna.
“The proof is within the pudding” as they are saying. It was time to really run a POTA activation with this antenna. The general size of the antenna was about 43 toes (about 13.1 meters), which is about 2/3rds the size of the 40m EFHW. This opens the potential of utilizing my 12 meter Spiderbeam mast (video evaluate) as a help quite than simply counting on a tree department.
The climate right here in NJ has been oppressively sizzling and humid with warmth indexes over 100F, so I opted for a morning activation, earlier than the warmth actually constructed up. The intent was to get some contacts on all three bands, regardless that 20m in all probability wouldn’t be very lively.
I setup at my “dwelling” park – Washington Rock State Park, US-1635. I made a decision to setup the Spiderbeam mast because the help for the brand new antenna:
The rig was my trusty KX2 with the BamaTech TP-III paddles:
I solely had about an hour to dedicate to working earlier than the household actions for the day, so I figured I’d begin on 40m and get many of the “ten” there first, then transfer on to choose up a number of on 30m and 20m.
I used to be capable of put 14 contacts within the log, underneath “so-so” band circumstances, which not less than a number of on every band, a number of of which had been park-to-park contacts.
Right here’s the map of the “attain” that the brand new antenna had throughout this quick activation:
Total I’m fairly happy with the antenna’s efficiency. The close to splendid band protection for my typical activations, and the convenience of deployment in comparison with the full-sized 40m EFHW make this antenna an ideal addition to my POTA equipment. I think it’s going to get a whole lot of use!
