Tag Archives: EFHW

POTA Field report: Pardon my French…

Sometimes we do things that take us outside of our comfort zone.

That’s exactly what I did on September 8, 2021 at Tuttle Educational State Forest (K-4861).

My friend, Jérôme, asked I would consider doing a POTA activation video in French!

Jérôme lives in France and wants to do a POTA activation there eventually, but had a number of questions about what to do in the field (spotting, logging, etc.). He’s been watching my videos for a while but admits that while he can understand written English (with the aid of Google Translate), he doesn’t understand spoken English.

Although I regularly listen to news and YouTube videos in French, it’s been ages since I’ve spoken French for any extended period of time.

Jérôme has been bugging me about the French video for some time, actually, but I’d put it off because there were a number of radio terms I simply never learned when I lived in France (well before I was a ham radio operator).

When he very diplomatically asked me again via email on the morning of September 8, I thought, “Why keep waiting? Just do it!

So I did.

Continue reading POTA Field report: Pardon my French…

Dan’s clever chalk line homebrew EFHW antenna

Many thanks to Dan (KQ8Q) who writes:

Hi Tom,

I discovered something you might have an interest in for your wire antenna deployment. Years ago when I was a building contractor, we used chalk line for floor layout. It has a very high tensile strength and is very light weight. After reflecting on this, I recently bought a 100’ spool of braided 1 millimeter chalk line and used it for a field deployment. I attached my “throw weight” to it and easily launched it about 60’ into a tree. You can see it in the attached photo holding my homebrew EFHW to my Jeep.

This link is what I used: Tajima PL-ITOL 100 ft .04″ Bold Braided Replacement Chalk Line New | eBay

Click here for full parts list (PDF)

The magnet wire was scavenged from a HUGE transformer from a neighbor’s discarded light fixture.

Lug Nut Throw Weight: left hand threaded from a 1966 Plymouth Fury

I did the new installation for him and he gave me the old one. I promptly disassembled it and collected miles of 14 and 20 gauge magnet wire 😊!

I haven’t added the capacitor to this antenna yet because it is sufficiently resonant and broadbanded on 40, 20, 15, and 10 Meters. I did some testing with the capacitors though on my previous build which was the PVC tube EFHW transformer. I believe I may have sent you a photo of that in a previous message. It too was resonant in the same places, but adding the capacitor smoothed and widened the acceptable SWR range.

The attached photos are my complete antenna assembly: matching transformer (49:1), 65.5’ speaker wire, 100’ braided 1MM chalk line, and throw weight (epoxy filled lug nut with short paracord pigtail).

Compact and lightweight.

Dan/ KQ8Q

I love this, Dan! I also like how self-contained and compact it is. What a professional job, too, with heat shrink, proper connection points and tie-offs.

Brilliant work!

Do you have an antenna or radio project you’d like to share on QRPer.com? Contact me!

POTA Field Report: Reviewing the MFJ-1984LP EFHF with the Icom IC-705 at Lake James State Park

I’ve been a ham radio operator since 1997, but until 2016, I had never purchased a pre-made portable antenna–I had always built my own.

During the 2016 NPOTA (National Parks On The Air) program, however, I purchased the EFT Trail-Friendly end fed 40, 20, and 10 meter resonant antenna and it quickly became my favorite field antenna. I found that it was simply built better than I could have built a similar antenna at home.

Pre-made antennas, though, come at a cost. Most time-tested, trail-friendly, portable antennas will typically set you back $90 US or more. You can make similar antennas much cheaper especially if you already have some of the parts (wire, toroids, RF ports, enclosures, etc).

Recently, while browsing the MFJ catalog, I stumbled upon the MFJ-1984LP End Fed Half Wave wire antenna designed for for field use and retailing for only $49.95 US.

That price point is very attractive because I believe if I built this antenna myself and needed to buy new parts, I might easily sink $20-25 in it.

Most MFJ products are manufactured in the USA and the company has an incredibly extensive and diverse selection of items in their catalog. Why I had forgotten they also sell antennas is a mystery to me.

MFJ is well-known for offering products that are basic,  affordable, and accessible (they’re available directly from the manufacturer and through most major radio retailers across the globe). I wouldn’t expect their antennas to be engineered like Chameleon Antenna, for example, but I would expect them to work well and get the job done.

I know the folks at MFJ and (in the spirit of full disclosure) they even sponsor QRPer.com, so I reached out to them and asked if I could evaluate their MFF-1984LP which is their most affordable field wire antenna.  They kindly sent one my way and I took it to the field last week.

I should add here that MFJ welcomes critical reviews, which is one of the reasons I asked them to be a sponsor. That and, well before they knew me, I was an anonymous customer and they repaired my MFJ roller inductor tuner for free a good two or three years after the warranty expired. My experience with MFJ has only been positive.

First impressions

The antenna looks exactly like the product photo in their catalog (see above).

For a field antenna, the coil enclosure is a little on the large side (especially compared with my EFT Trail-Friendly), but it’s still very backpack-able. Knowing MFJ, they kept costs at bay by using one of their standard enclosure boxes for this antenna.

The enclosure also has an open grill to allow the coil to dissipate heat (see above). I found that a bit surprising since the core is so large inside, but I assume some heat must be generated if you’re running 50% duty at a full 30 watts (the maximum rated power). The matching network impedance ratio is 49:1, so there will be loss and heat.

The 66 foot radiator wire has a dark jacket that glides nicely over tree limbs and doesn’t encourage tangling when unwinding.

The end insulator is made of a thin plastic/composite material that is lightweight and shaped so that it won’t snag on tree limbs.

To the field!

Hey–the proof is in the pudding, right? Let’s put this antenna on the air and make a real-time video of the activation!

Last Wednesday (February 17, 2021), there was a break in the weather so I made a detour to Lake James State Park (K-2739) en route to visit my parents for a few days. I left the house without deciding what park to activate, but picked Lake James because I knew I would have access to tall trees and my pick of operating locations.

Gear:

Deploying the MFJ-1984LP is no different than deploying any other wire antenna. It was super easy using my arborist throw line. That thin, rounded end insulator did certainly glide through the tree branches with ease. No hint of snagging.

On The Air

I connected the antenna directly to my IC-705 with no ATU in-line. Hypothetically, I knew this antenna should be resonant on 20 meters where I planned to start the activation.

Keep in mind that pre-made antennas are often designed to be a tad long and need to be trimmed so the operator can tweak the resonant point for their preferred spots on the band. Since I tend to use the lower part of the band for CW, I typically leave my antennas with a resonant point somewhere on the upper side of the CW portion of the bands. It’s not super critical for EFHW antennas because they tend to have ample bandwidth to give a full meter band good matches.

I had not trimmed the MFJ-1984LP, but decided it should be “resonant enough” for my purposes.

I found a clear frequency on 20 meters and checked the SWR. It was spot on at 1.3:1 on 14,031 kHz! Woo hoo!

I started calling CQ and collected several stations in short order despite the poor propagation that day.

I then moved to the 40 meter band and discovered the antenna also gave me an excellent match there. I started calling CQ POTA and was rewarded with a steady stream of contacts.

I imagine I could have racked up a lot of contacts at that activation, but I made up my mind that I wanted to fit in another quick activation afterwards, so cut it a bit short.

In the end, here’s a map of my 18 contacts made in 26 minutes of on-air time:

Not bad for five watts and a wire!

Video

I made a real-time, real-life, no edit video of this activation which starts shortly after I deployed the MFJ-1984LP and ends a few moments after my last QSO. Against my better judgement, it includes all of my mistakes (including my inability to form the number 4 that day!):

Click here to view on YouTube.

MFJ-1984LP summary

No antenna is perfect and each time I start a product review, I keep a list of pros and cons. Here’s my list for this EFHW antenna:

Pros:

  • Very affordable at $49.95
  • Effective: results so far have been excellent
  • EFHW is a proven field antenna design and resonant on several bands
  • No coil on the radiator to snag in trees (see con)
  • Backed by MFJ warranty
  • Purchase supports US manufacturing

Cons:

  • Bulkier than comparable low power field antennas
  • No built-in winder (MFJ should consider altering the design to include one!)
  • Radiator is 66 feet long since there is no in-line coil to electrically shorten the length (see pro)
  • End insulator is effective, but feels slightly flimsy

In the end, there’s no magic here: the end fed half wave is a time-tested, proven antenna design and the MFJ-1984LP delivers. In terms of performance, I couldn’t be more pleased with it right out of the box. This isn’t a military-grade antenna, but it should last for years with proper use.

POTA activators that have access to trees in the field will appreciate the MFJ-1984LP. I should think you could also make an effective “V” shaped antenna if you have a telescoping support that’s 29-33′ tall.

I’m not so sure the average SOTA operator would find this antenna design as convenient–especially on high summits where you’re near or above the tree line. It could be difficult deploying a 66′ wire. That and this antenna is bulkier than other designs. If you’re backpacking it in, you typically want the most compact solution possible (this is where the EFT Trail-Friendly, Packtenna, and QRPguys designs really shine).

I will certainly employ the MFF-1984LP regularly–especially on days with less-than-stellar propagation.  I think this might become a go-to antenna for the MTR-3B, LD-11, and IC-705 since all of them lack an internal ATU.

If you’re looking for an affordable, effective wire antenna, I can certainly recommend the MFJ-1984LP.

Do you have an MFJ end fed half wave antenna? What are your thoughts?

Click here to check out the MFJ-1984LP at MFJ’s website, and click here to download the PDF manual.