Why would anyone want one of these you might ask?
I mean don’t get me wrong, EFHW antennas are my favorite setup for QRP in the field. What’s not to like about throwing a line over a tree limb and hoisting up a sloper?
But 80M is not really a SOTA band and setting up an 80M antenna in the field is asking a lot IMO.
So why bother? For me it’s a necessity because my primary goal of a portable QRP rig is to provide NVIS comms with my wife should things ever go sideways while I’m at work 50+ miles away and have to hike home because the car is no longer an option as in the case of an EMP, CME, Earthquake. Hopefully SMS texting will till be working, but if I relied solely on that, I would have no excuse to buy radios!!!
NVIS means 80M if you are going to talk at night. Hopefully 40M will do the trick during the day, but I wanted to have the ability to work both bands without a tuner.
The QRP-Guys kit fits the bill perfectly!
Previously I was packing my Emtech ZM-2 ATU and a random wire, but this year I decided to simplify and use resonant wires only. Not only does this maximize your power out, it eliminates a point of failure, which is always a good idea!
For 20M/40M, the trusty LNR 10/20/40 “Trail-Friendly” EFHW was a no-brainier, but getting 80M required a little more research.
As a side note, I’m not sure where you can get this antenna anymore now that LNR no longer sells them, but this thing rocks! I was “booming” into Northern California today on it with 10W on 40M SSB, great piece of kit!
My first thought to add 80M was to switch to the SOTA (Band Hopper IV) to cover the whole spectrum between 20-80M, but putting up a 157ft linked dipole to work 40M or 20M just didn’t make sense to me. Not to mention that a dipole needs a long coax to reach the center feed point which is the highest point if you plan to use it as an Inverted-V. Consider that as opposed to a 3ft length for an EFHW anchored next to your rig.
Knowing I didn’t want a tuner, and having passed on the linked dipole, that left a matching circuit setup like the one found in the QRP-Guys No Tune End Fed Half Wave Antenna kit.
The kit itself was caveman-simple and took about 20 minutes to complete. It was my first kit ever, so when they say “Easy” they mean it. Even so, I did manage to break it before ever using it as shown in the top center picture below!
I wound the wire onto the PC Board and pushed the BNC connector anchors our of there clip holes and bent them all up. To make sure they stayed secured, I soldiered them in and moved on.
Just be careful how you wind the wire onto it the unit or you can go the way I did and solve the issue by using a larger kite winder.
Our tests have been favorable for ≤2.0 SWR or better for the entire band, except 80m, which can be optimized for the upper or lower portion of the band.QRP-Guys
I found the above quote from their website to be accurate, and by adding 130ft of Wireman #26awg, I was in bottom of the 80M range with 1:1 @ 3.700. They recommend a starting point of 125ft on the kit.
By hanging the wire in a sloper config outside the shack and running back and forth to tune up and down the band with my trusty MFJ-941E (someday I’ll get an antenna analyzer!) I wound up trimming the driven element to 133.5ft to get:
- 1:1 @ 3.818 (AmRRON 80M Voice)
- 1.5 @ 3.980 (Oregon Emergency Net)
- 2:1 @ 3.700 (Bottom of band)
I’m very happy with these results and will be curious to see how it performs in the field as an NVIS setup in the 0-50 mile range that I’m trying to establish comms in.
I will be testing this and the LNR “Trail Friendly” as soon as HRO brings me the TX-500, hopefully at the end of the month a their website is showing.
It’s marginal 10W will be the consideration for NVIS, but you never know what will work until you try it, right?
Anyway, If you are considering adding such an animal to your kit, I recommend this one!
At $20.0 for the kit, and another $35 for 140ft of wire, it’s hard to beat.