N4REE – Minimalist Ham – Page 3 – Code rehab forever

Testing the KJ6ER PERformer Vertical Antenna

November 21, 2024 by Bob Easton 1 Comment

The Casa Easton Antenna Test Range has been busy the past few days. About 2 weeks ago, I discovered KJ6ER, Greg Mihran’s, PERformer (Portable, Elevated, Resonant) antenna. Greg describes the antenna in spectacular detail in a frequently updated document. He has extensively modeled the antenna for 40M through 6M. I built mine for 20M through 10M, especially for use with my QMX transceiver.

Bottom line: This one’s a KEEPER! Advice: Greg has a DONATE button as part of his fine article. I suggest using it to recognize his good work.

My problem with elevated vertical antennas

Several hams, WB3GCK, Craig La Barge, and WK4DS, David Saylors, in particular, talk about using elevated antennas atop poles mounted on the back of their trucks. They use them with tuned raised radials and they have great results at QRP power levels.

I’ve tried elevated antennas and raised radials on my own antenna test range and haven’t yet matched their results. However, I’ve not had good measurements for the various components. Guesswork resulted in functioning antennas, but not in the kind of results Craig and David report.

Until…

The KJ6ER description brought it all home for me. KJ6ER, Greg, describes his modelling, includes several tables showing measurements, and offers construction ideas. All are great starting points.

I modified a stand I had previously used for elevated antenna testing, making it the height Greg suggested, 52 inches. A quick trial with a 17′ whip adjusted to a 15m length and 2 raised radials at Greg’s suggested lengths enabled the very first QSO, an easy 5w QSO, from Central Florida to KR7Q, Clifford, in the mountains of western Montana. BAM! I was hooked.

Next, improve the components. My old 17′ whip was rickety, showing dancing SWR indications as the wind blows and sometimes having a section or two spontaneously collapse. Replacing it with a new Chameleon SS17 fixed that problem. Then, I constructed a pair of linked radials for 10m, 12m, 15m, 17m, and 20m similar to those Greg describes. (I used his exact lengths.) Lastly, I rebuilt the simple little Common Mode Choke that you see dangling between the whip and the feedline. It keeps stray RF off the feedline and offers consistent SWR that doesn’t involve the feedline acting as a random radial.

My antenna test range is my backyard. I setup the antenna as you see it with a couple of plastic electric fence sticks as end points for the radials. A short segment, made of paracord, can be moved from segment to segment in the linked radials to select bands. Through testing, I found vertical element lengths that were optimum for each band in this configuration. I discovered that the best way to adjust it is to set the vertical element a bit longer than the lengths in the table, and then reach up and fiddle with the 2nd section of the whip, which is just within my reach. So far, I’ve used the radials 90 degrees to each other, which Greg’s models show a modest bit of directionality. For these tests, and that Montana QSO, they were pointed WNW.

Results

I measured with a NanoVNA, and then with WSPR. Antenna lengths were tuned for lowest SWR in the CW portions of the bands, usually the QRP hailing frequency. I frequently use WSPR to discover an antenna’s potential, and treat WSPR results as a “possibility,” never a guarantee. Each of these WSPR runs were mid to late afternoon in the US Eastern timezone, with each run for 6 minutes. Solar Ham showed this as a typical propagation day, no solar storms.

These are the lowest SWR results I’ve seen in any of my testing.

Band	Radial lth	Radiator lth	SWR	Impedance
10m	80″	114″	1.031:1	50.7Ω
12m	96″	124.5″	1.045:1	51.1Ω
15m	120″	143.5″	1.027:1	48.7Ω
17m	149″	163″	1.049:1	49.7Ω
20m	198″	207.25″	1.041:1	48.1Ω

Compared to other Casa Easton Test Range antennas

Long ago, I crawled around burying 18 radials in the grass. I use that field with either a Wolf River Coils antenna or with Hamsticks, all sitting atop a low tripod. They’ve produced ~almost~ continental coverage, and always enough capability to reach hundreds upon hundreds of mid-continental POTA activators. SWR with those configurations run between 1.3:1 and 1:7:1, never lower.

My vertical dipole, A DX Engineering Transworld 2010 (TW2010) has also offered reliable mid-continental results, and maybe longer reach than the verticals atop the radial field. It’s advantage is quick setup, even tough it does need more than the usual amount of coax for impedance balance … and SWR in the 1.2:1 to 1.4:1 range. The difference is so slight (in actual listening) as to not be noticeable. Knowing what I know of it now, I shouldn’t have spent that much on it.

DIY-built EFHW and EFRW inverted Vees have almost always performed better than the verticals over the radial field. I’m continually playing with variations and am usually pleased with how well they work, especially the ease of changing bands.

Which brings me to the PERformer. KJ6ER, Greg, shows his models demonstrating efficiency factors about 30% better than most of my other antennas, and some directional front-to-back gain. So far, I’ve had delightfully solid results and at least one contact well beyond the normal range of my other antennas, possibly confirming the directional gain. A too-short session yesterday brought a quick string of POTA QSOs at higher than usual signal reports. I’m not quite gushing yet, but I have thanked Greg and remind you to push his DONATE button when you see the same results I have.

Time will tell. (Hey Alaska, are you hearin’ me?)

Bonus material

KB9VBR, Michael Martens excellently describes details of his build and his results below. Pay particular attention to the last / summary section.

FT8

September 6, 2024 by Bob Easton Leave a Comment

So then he says, Let me show you my logbook. It was all FT8!

Nuff said. Because you can’t really say anything on FT8.

jason VE5REV responds: Like callsigns & signal reports? Can we exchange that information with FT8? Can we see propagation patterns with minimal power?? Can we use it when other modes won’t work due to bad band conditions???

QMX – High band version – kit built

August 2, 2024 by Bob Easton 3 Comments

Introduction

The QMX is a tiny little multiband, multimode, software defined transceiver, from QRP Labs, that runs at QRP power, roughly 5 watts output. Mine is the “High Band” version covering 6 bands from 20 meters through 10 meters. While designed for CW, various digital modes, and SSB, my interest is (you guessed it) CW.

Mine is kit built. I like building things, and building allowed me to acquire a working QMX several months earlier than waiting for an assembled version.

This radio is one version of a series designed by Hans Summers, G0UPL / AF7BF. I am most impressed by how compactly it is packaged. The parts are packed in so densely that successful assembly requires sharp vision, tiny soldering iron tips, and a jewelers loupe. Click on any of the images and then click again to see how dense things are. My successful assembly came by working in small steps and inspecting constantly with that loupe.

Rather than writing more about the technical details of this radio, you might want to read Hans’ own description of how he developed it, a fascinating read for those who like evolution stories.

Assembly done – Let’s start testing

Jul 12, 2024 – At first, I thought it wasn’t getting power correctly.

Yes, the instructions say that when first powered connected PC sees it as a thumb drive. It also says there is nothing displayed. Yet, somehow I still expected ~some~ sign of life and saw none … other than the bench power supply showing about 1/8 A power draw. (I had it set for 7 vDC and .250 A) I also have an inline voltage regulator set for 7 volts. It is extra protection to avoid voltages over 12.0, but set to 7 for initial testing.

Look closer! Yes, there is a drive named “QMX” on the PC. Drag the firmware file, 1_00_020.QMX to that drive. Drop power. Power up again and be greeted by “Initializing EPROM,” and other messages. Voila! It works without emitting smoke.

Next, CONFIGURE and test …

Jul 13 – 2024 – First RX tests: After a round of thunderstorms, I connected the HS20 antenna and listened on 20M for a while. This little rig sounds ~almost~ as good as the TR-45L, but has only one CW filter*, 300Hz, which is a reasonable choice. Its audio is FAR better than the (tr)uSDX with enough amplitude that I don’t need the follow-on audio amp, and no unexpected squealing so far.

*update: More filtering options appear in firmware version 23.

So far, so good. Let’s move up to “normal” input power, 11.7v.

Band	Power output	Power drawn
20M – 14Mhz	4.06 watts	0.582 A
17M – 18 Mhz	5.61 watts	0.797 A
15M – 21 Mhz	5.64 watts	0.903 A
12M – 24 Mhz	3.93 watts	0.743 A
11M – 27 Mhz	4.05 watts	0.772 A
10M – 28 Mhz	3.63 watts	0.718 A

Jul 14, 2024 – First quick TX tests (key down for 2 seconds) RF power output was with about 11.7v from a Talentcell battery, RF output goes to my QRPoMeter SWR/PWR meter, then to a dummy load. Power drawn was measured from a bench power supply.

On the air: As of Jul 31, 2024 the QMX has enabled quite a few POTA QSOs. I’m pleased with its performance and use it for those bands the TR-45L doesn’t cover.

Update: Oct 18, 2024 – Dozens of QSOs have flowed through this little radio. Yesterday, it helped drive the fun-o-meter way above max. That came from a QSO with Paul Butzi, W7PFB out in the woods in Washington state. I parked on his frequency until I started hearing very faint CW. The usual advice is to avoid trying to contact until you’re absolutely certain of 100% copy. I broke that rule, at the 99 and 44/100s mark. (Oldsters will understand the reference.) Thanks to Paul’s sharp ears, we made it work at the 229 RST level. Thanks Paul!
[fun-o-meter image “borrowed” from Paul’s QRZ page.]

Overall, the radio is a joy to use. Hans, the designer, developed a user interface that is very easy to manage, and the radio has the sensitivity and audio characteristics that obviously perform well for weak signal work. As much as people praise the TR-45L for excellent audio, I enjoy the QMX audio more. It seems to have a better SNR than the TR-45L, and recent filter updates have let me move zero-beat and sidetone frequencies to something more pleasant to my hearing.

Next… AK and HI.

T41-EP SDT “Pop-Pop” (3 of ?)

July 20, 2024 by Bob Easton Leave a Comment

When we last visited this radio, it was almost complete. That’s when I decided to switch out the power amplifier. The “-EP” in the name means “Experimental Platform.” Let’s experiment. The reason is because of reports of poor power output on higher bands due to the original power amplifier using transistors with a very steep output falloff above 20 Mhz. A newer power amp has a much flatter frequency response at 20 watts output. (I only want 5, but will appreciate the extra headroom.)

The semi-kit by K9HZ Bill Schmidt arrives as a PCB (Printed Circuit Board), a few semiconductors, a few transformer cores, some wire, and a BOM (Bill Of Material) for the rest of the parts. Almost all of the parts were SMD (Surface Mount Devices), giving me the opportunity to learn a new skill. 🙂 Despite needing a very good magnifying glass and a jeweler’s loupe, construction went very well.

So did initial power testing. The fun came along at the next stage, when the “bias” potentiometers are adjusted to produce the correct current flow through each of the power transistors. For that, the amp needed a signal voltage from the transceiver. So, I mounted it in the case and hooked up power.

A very quick “POP-POP” was the response on flipping the rig’s power switch. Puffs of smoke from new holes in the power transistors floated up. All electronic devices are powered by smoke and once you let the smoke out, they no longer work. ;{

What the???? User error, of course. Wrong polarity power. I tried using a new battery, a new LiFePO4. It is a very nice battery that will serve well as a base station power source. My mistake was NOT making up new power cables, but using a couple that were in the box. Hey, these two fit together. I blithely went ahead without realizing that using them in series, instead of alone, produced a polarity reversal. Stupid error! … POP-POP and along with it lesser POPs and PFFFTs inside the mostly complete T41.

As I write this, I don’t know the extent of the collateral damage. After replacing a few parts on the power board, the rest of the T41 does not come to life and there are significant voltage drops on the 5V line. It may be time for an extensive rebuild.
UPDATE: There are enough “anomalies” with the existing build that I’ve decided to rebuild completely using the V12 version of the T41. More function, refined RF specs, and known-good hardware are some of the reasons.

Meanwhile, I can easily rebuild, and correctly test the power amp. It is independent of the main radio and easily rebuilt.

P.S. Safety glasses recommended for first power. In this case, it was under a magnifying glass which stopped the remnants.

Antenna shootout: Hamsticks vs TW2010

June 8, 2024 by Bob Easton 2 Comments

After taming the Hamsticks, I turned my attention to effectiveness. How do these antennas compare to another in my collection?

Contestant 1: Hamstick verticals

I have used various forms of 1/4 wave ground mounted verticals, including the Hamsticks, for quite a while. They have the attributes of being relatively low cost, easy to setup almost anywhere, and will perform. Yes, everyone calls them “compromised,” but that’s a term that can be applied to most any antenna. I use my verticals as “backyard portable” from my home QTH in the midst of an HOA community. I have no objections from wonderful neighbors, and no complaints from passers-by who probably can’t even spot the antennas.

There’s a radial field under the antenna, 16 radials of 18 feet each.

For some Hamstick variations, I use loosely deployed radials above ground. See the taming article for more details.

For almost all verticals, dragonflies are attracted to the tops. Dunno why.

Contestant 2: DX Engineering TransWorld 2010

I also use a DX Engineering TW2010 from time to time for the 20M through 10M bands. The TW2010 is a 5 band vertical dipole. Each side of the dipole is a “T” shaped section. A box between those sections contains a group of loading coils. It is about 5 feet wide and stands 8 and 1/4 feet tall. DX Engineering originally acquired the design from someone else and then set about its own manufacturing. I can confirm that it is well built, of fine quality materials, and engineered for easy set-up.

The only complaint about the physical form is that the 4 legged base occasionally spontaneously self-disassembles. (Thanks Elon for that description.)

DX Engineering describes the antenna as “portable” because they offer a carry bag about the size of the typical golf bag. Now, add to the antenna parts the 65 feet of coax that’s used for impedance matching, and the “portable” antenna becomes, in my mind, not man portable, but truck portable. … about 30 pounds.

P.S. KA3DRR, Scott Morrison, drags his TW2010 around in a wagon he calls Land Rover One. He’s not one of those strong healthy young males who grumble about the difference between a 9 ounce radio and a 14 ounce radio. 🙂

The competition

Some of the YouTube ham personalities review antennas by describing them in manufacturers’ terms, showing how they are assembled, and usually taking them outside somewhere, hooking up 100w SSB transceiver and making a few calls. “See, it works!”

Of course it does, almost everything does. If K0KLB, Kevin Behn, can loads up his grain auger or hay wagon at QRP power and make contacts, almost any other antenna “works.”

I’m more of a data person. Fifty years in the IT business, and the delight of working many of those years in a research laboratory, does that to a person. I like data to support conclusions. So, I use a ZachTek WSPR Transmitter to check out antennas. WSPR is Weak Signal Propagation Reporter, a network of radio stations that listen for specifically coded signals and file them in a searchable database.

For these tests, I set up 12 minute runs for each antenna in midday on May 27. Midday is not optimal for any particular band, so results don’t indicate the best that can be achieved during peak propagation periods. But, the results do show relative performance of each antenna compared to another. Yes, there are those who say propagation conditions vary constantly, and I agree. Running 6 tests as close together as possible is the best that I can do to mitigate constant change. I collected results using the wspr.rocks site, one of several that collect WSPR data.

There are three rounds of tests, each individual test running for 12 minutes:

TW2010 set for 20M vs a 20M Hamstick with a radial field in the grass
TW2010 set for 15M vs a 15M Hamstick with 3 loose radials on the ground
TW2010 set for 10M vs a 10M Hamstick with 3 loose radials on the ground

	Spots	Avg SNR (dB)	Max KM	Spots @ Max
TW 20M	190	-17	3808	1
HS 20M	121	-18	3808	1
TW 15M	103	-17	6466	4
HS 15M	88	-18	6466	6
TW 10M	72	-18	4251	3
HS 10M	50	-20	4213	4

Counting spots, the TW2010 performed better than each comparable Hamstick. That’s not really a surprise since well tuned dipoles usually outperform 1/4 wavelength verticals. The margins for numbers of spots are 35% better on 20M, 15% better on 15M and 31% better on 10M.

As for reach, the Maximum Kilometer distances are almost identical, with outliers for both antenna versions. At max distance, the Hamsticks have more hits which seems a disparity from the overall spot counts. The SNR averages are only 1 to 2 dB difference, with the Hamsticks showing a stronger average. So, why is it they have a lower number of spots? Tis a puzzlement…

For the graphic record, here are 6 maps corresponding with the 6 runs.

Turning from data to reality, I’ve made 6 QSOs from my Florida QTH to Oregon: 1 with the 20M Hamstick, 2 with the 20M TW2010, 2 with the 20M Wolf River Coils 17’whip, 1 with the 15M Wolf River Coils 17′ whip , most on different days, different times, different RSTs. so, yes all of these antennas “work.” 🙂

In the end, a subjective question remains: Is it worth paying about 6 times more for the TW2010 than for my collection of Hamsticks?

UPDATE 10/20/24: Two recent events happened recently with the TW2010.

A QSO with Paul Butzi, W7PFB out in the woods in Washington state. I’ve been chasing POTA for a long time, and WA is a LONG way from FL. Paul and I made a faint QSO, via the TW2010 and my QMX on my end and 10W into a a Chelegance MC-750 on his end.
The next day, frequency agility worked very well on the TW2010 as I made QSOs on all of its bands, 10m, 12m, 15m, 17m, 20m. Yes, I have Hamsticks for each of those bands, but band switching was easier with the TW2010’s “U” plugs, even faster than the Hamstick quick disconnects. Good propagation days and beautiful fall weather brings out POTA activators on all bands.

Taming my Shark HamSticks

May 27, 2024 by Bob Easton Leave a Comment

Neighbors near me in this HOA location are very tolerant of my “backyard portable” vertical antennas. The antennas are not obtrusive in appearance, use little space and work reasonably well considering they are not multi element yagis on a 60′ tower.

For some time, I worked with Wolf River Coils verticals on 40M, 30M, 20M. I use them on a tripod sitting over a radial field of 18 radials, each about 16′ long. While reasonably effective, changing bands is really fussy. Get out the NanoVNA, adjust the coil, adjust the whip length, repeat until good enough for the transmitter to be happy. Wash, rinse, repeat…

Some will suggest a multiband vertical instead. Even though I had a good experience with a fellow ham’s 6BTV, I’m not willing to live with its equally fussy tuning and losses, esp when it’s hidden inside a flagpole and every adjustment is a sequence of: lower the pole, uncover the antenna, adjust, re-cover the antenna and re-raise the pole, quite an ordeal.

So, I had the idea that I could acquire a collection of Hamsticks (40M, 30M, 15M, 10M) tune ’em once, install quick-change adapters on them and have band changes within seconds. BZZZZZZZZZT! A couple of them worked OK above my radial field. The others wouldn’t. We read frequently that more radials are always better, and Callum tells us that up to a certain point that’s true.

More radials: It Ain’t Necessarily So

Gershwin tried to tell us… I spent a lot of time yesterday trying each of these HamSticks in different configurations. My goal was to discover the configuration of each with the lowest SWR, as indicated by a NanoVNA.

My first variable included trying them directly atop the WRC tripod and then atop 1 or 2 aluminum extensions, 24″ long, that are part of the Wolf River Coils family. Only one of the HamSticks liked to be atop the extensions. The 40M stick worked out best atop two 24″ extensions. All the rest sit directly on the tripod.

My second variable included different radial configurations: (1) the in-the-grass radial field, (2) a set of 3 radials each 33 feet long, and later (3) some shorter ones. The 40M and 20M sticks were OK with the 18x 16′ in-the-grass radial field. The others wanted shorter radials. The 15M stick liked 3×33′ radials better (1.572 vs 2.100). Next, I folded those in half and got even better results. After that revelation, I reduced the 3 radials to 1/4 wavelength for 15M, 11 feet each, and found yet better results. Same thing for 10M. Three really short radials outperform a bigger radial field. Who would’ve guessed?

Photo of one hamstick mounted on the WRC tripod and the other three leaning against a wall

Of course, these measures of goodness are simply SWR numbers from a test device. On air performance is the real test. I’ve already made on-air contacts with all of them. My next round of measured testing will be WSPR runs.

Till then, this chart sums up my test results. I’ll be using he bold entries to make band changes fast, easy and tuner-free.