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Topics - dylan

Hi everyone. I had a recent opportunity to take an MTR5b and 40m EFHW setup deep into the wilderness. Similar setup to last year's "radio vacation" ( The 40m EFHW was tuned via QRPGuys EFHW tuner, with driven element / counterpoise lengths from their recommendations. I was able to get the high end of the antenna up about 40 feet thanks to some conveniently placed trees and topography. Sounds like a great setup, right?

I found that I could "hear" stations all over the US at 0200 UTC (local time ~ 7pm) but could not make contact with a station about 50 miles away that was listening/transmitting. I used VOCAP ( to estimate the potential for said contact, and the predictions left me confident (see attached forecast). It seemed like 40m at 0200 UTC would be within the realm of possibility when using 1W CW on my end, and 15W on the other end. Note that the other station was using a 40m doublet at about 20 feet elevation, north-south orientation. I was north-east of the other station.

A couple of observations and questions for the group.

  • The EFHW + tuner combination seems to do well when the tuner is elevated at least 3-4 feet off the ground, any closer and it is difficult to achieve and SWR less than 2:1.
  • What kind of theoretical radiation pattern can one expect from an EFHF? I recognize that there are over 1,000 answers depending on the local conditions, but could there be any rules of thumb to go by? For example, one can expect maximum signal strength in the horizontal plane at 90 degree angles to the orientation of a 1/4 wave dipole at resonance.
  • Was the skip distance under those conditions / antenna the likely problem (overshoot) or antenna directionality?
  • Is it possible to achieve NVIZ-type communications with a EFHF?
  • Are gound-losses too high for NVIZ to function properly at < 5W of power?

Overall, I'd bring the QRP kit (MTR5b, 40m EFHF, QRPGuys tuner, mini-paddle, ear buds, 9V battery) on my next backpacking trip as it contributed very little weight.

I'll have it out again next week in case anyone would like to schedule a QSO on 20/40m.


Net Activity / Radio Vacation
July 29, 2018, 05:56:38 PM
Hi folks. Thanks for sharing so many great stories, reviews, and ideas.

I am planning to be on 20 and 40 meters CW this week, operating with an MTR5b and EFHW antenna from the north coast of California. I'll likely be hanging out near the middle of the CW portion of the bands, between 1-3pm pacific standard time. I think that is a -7 GMT offset. I'll send a photo and review of my temporary station once I get it setup.