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QRPguys EFHW? No tune with FT-817

Hi, I’m going to start doing some SOTA activations soon, and was looking for a simple antenna that is easy to deploy and use without a tuner, mainly on 20 and 40m (CW) with my FT-817 and 25 ft of RG174. Anyone have any luck with the qrpguys no-tune EFHW?

Thanks!

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Thanks

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I have not used their kit, however have built a few antennas of same design though with larger ferrite core. If you wind it per instructions and keep uniform spacing it will work quite well. Can be used with ~66 feet of wire for 40 - 1 meters, or as a single band with wire cut for each individual band.

If you like, there is a 40/20 shortened dipole kit that is also easy to build from Pacific Antenna. I have built it and it is rather easy and it works quite well.

https://www.qrpkits.com/dualbanddipole.html

73,
Howard KE6MAK

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Thanks for the reply Howard. You are the second person that has recommended the pacific antenna 40/20 dipole. I might pick one up in the future. I’m guessing that you don’t need a tuner for that antenna, correct?

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I have to recommend the Pacific Antenna dual band trapped dipole. Over 100 activations with 1. Only replace with a homebrew EFHW that speeds things up a lot.

Malen
VE6VID

Thanks. Did you use a tuner with the Pacific Antenna 20/40 trapped dipole?

No tuner at all once the dipole was constructed and tuned. I used an antenna analyzer to tune it.
I ran 40-60 watts into it. It went thru a beating with trees, etc. I actually got it tangled up in branches and had to pull hard on it and it survived without damage.

Malen
VE6VID

The loss from the broadband matching device is twice the loss from the tunable matching device in my tests. The loss is low, only about one DB (vs a half DB) if the SWR is low. IF the SWR is above 1.5:1 the loss in the broadband matching device goes up exponentially. You will find with this broadband matching device the SWR never seems to go above about 4:1 because it is acting like a dummy load. Variation in the environment such as wet vs dry ground, rock vs soil, trees vs none, different heights, different poles, can cause the wire to no longer be exactly tuned the way it was in the back yard.

Loss with RG174 can be significant at frequencies above ten MHZ. If you start to add losses while running very low power, it can mean the difference between QSO and no QSO. If you use a feedline, I don’t, better coax that is short isn’t going to weigh any more and so might as well be used.

I don’t use a feedline at all. An endfed HALFWAVE has essentially no current, no radiation at the end of the wire. I simply use four feet of the EFHW as my feedline.

All these antennas and the matching devices can be made yourself at a fraction of the cost. Making and tuning them is educational.

73 fred kt5x / ws0ta

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Cam,
Same as what MalenVE6VID said; once tuned it doesn’t need a tuner, tuned mine for ~ center of 40 and it covers the whole General portion of the band, a bit wider range on 20. Inexpensive and easy to assemble with the coil forms being drilled at the right points and the lengths they suggest will need to be pruned which is much easier that cutting it longer. :sunglasses:

Howard KE6MAK

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Thanks!

What is noticeable about the EFHW, and little mentioned, is that resonance is well off on harmonic bands (without adjusting length for each band, or using a tuner). The harmonics are well high in frequency.
e.g. if the fundamental is 3.5MHz, 2F=7.3, 3F=14.8

I have a few extra metres of wire joined at the feed end that I either slide up the antenna for 80m or slide down the guy string to lengthen it for 40m or 20m. (the feed stays at the same point)

I will be trying this arrangement of a small loading coil , to bring the resonances together, soon.

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Hi Cameron.

I use the No Tune End Fed for 40m and 80m among other antennas from QRPguys.

Once set up, measured with an antenna analyzer and done they play very well. I use additionally a very light wire (Antenna wire from aramid (Kevlar®) fiber).

If you want to be more flexible I can recommend the UnUnTenna with AutoTuner or the UnUnTenna Plus. Of course depending on how much space you have to stretch the wire.

Otherwise just go ahead and try different antennas :wink: :+1:

73 Marcel DM3FAM

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Thanks all for the ideas. I don’t have an antenna tuner, but can find a sweet spot using the SWR gauge that’s built in to the FT817. Thanks!

Cameron.

Take a look at the UnUnTenna Plus (https://qrpguys.com/ununtenna-plus). This one has a small matchbox included. So you can be QRV on different frequencies and can tune manually. As an indicator you can use the SWR of the FT817 and the LED of the UnUnTenna Plus.

73 Marcel DM3FAM

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Hey Cameron, another NoVA SOTA guy here. :slightly_smiling_face:

When I had an 817, I used the QRPGuys No-Tune EFHW mentioned above or the QRPKits SOTA EFHW Tuner with 70-some feet of 26awg wire on a chalk reel marked at the appropriate lengths for the tuner. Both worked well and the QRPKits tuner was really tiny.

What summit are you going to try first?

ETA: If you’re on FB, join the Appalachia SOTA group. Most of the members and activations are semi-local to our area. Also, 2m FM is VERY productive around here. I’ve done most of my activations this year via 2m FM.

Chris

Thanks Chris. I’ll check out that tuner, and the FB group. I am going to try this summit next month when I go to NC on vacation: W4C/EM-114. I also plan on going to Shenandoah this spring to try some activations.

I took the QRPGuys No-Tune kit and turned it into a linked 20/30/40 EFHW and have had great success with it.

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There are also lots of good summits on Skyline. If you need any guidance, let me know.

Also, Blue Mtn, SH-030, is pretty convenient from NoVA, but has horrible VHF-affecting QRM due to the radio towers. HF works great there though.

Chris

I never considered that. It would be an interesting idea…

Now I wish I hadn’t sold mine along with my 817nd.

ETA: Assume you did that with traps? Or just jumpers to “break” the radiator at defined points?

Chris