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Coast to Coast with “Quirky Lil Orange”

April 27, 2024 by Bob Easton Leave a Comment

map of contacts made with the (tr)uSDX transceiver

While not technically on the coast, my QTH in Central Florida is on a peninsula hanging out into the Atlantic Ocean, and the other end of these QSOs is in a Pacific Palisades costal park in Oregon. I had 2 CW QSOs with Zack, K7FC, who was in the Oregon Coast State Trail park, US-10007, along the coast west of Salem. One was on 15m, the other a few minutes later on 20m. Zach reported the 15m QSO was the stronger one. Distance calculations show that to be 2533 miles, 4076 km, as the radio waves fly. The fun part was making these QSOs using 2-3 watts with a quirky little orange radio.

Every review I’ve read about the (tr)uSDX radio praises how much function is packed into a tiny package. It’s a 5 watt, 5 band, multimode radio developed by 2 hams, DL2MAN and PE1NNZ. Nearly all reviews praise good performance, but complain of poor quality audio and quirky audio behavior. Much of that criticism stems from a miniscule “emergency use only” speaker coupled with a design deficiency which allows unexpected audio overdrive, squeal, in certain situations. I complete the name “Quirky Lil Orange” with that color because mine is housed in a printed case that is indeed very orange.

photo of (tr)uSDX transceiver and morse key
photo of (tr)uSDX High Band kit components

I like building things. So, I built the “High Band” version of the radio which operates on the 20M, 17M, 15M, 12M, 10M bands. Information about the radio warns of lower performance on the higher bands, but they are exactly why I wanted it. Yes, performance / output is lower, in the 2 to 3 watt neighborhood, but experience, like the Oregon QSOs, shows me that sheer power isn’t everything.

Now, about the audio quirks… The squeal monster is uncaged when the audio level is at or above 12 (out of 16). Avoid the problem by staying at or below volume level 12 … and not hearing weak signals. My answer is to use headphones, which is what I prefer anyway. I bump up the volume with an inline eSynic (quirky spelling) headphone amplifier (NOT an affiliate link). For power, I use a Talentcell 12.6v Lithium Ion battery (also NOT an affiliate link). Not liking to string all the parts out in a chain across a table, and since they’re all similar sizes, I used a couple of velcro strips to bundle them together in a sandwich. Neat, and compact. A little stick of nice mahogany held in place with double sided tape makes the kickstand.

For the record, since the (tr)uSDX offers so many measurements, here are power outputs it reports for the various bands today. As an aside, tedious tweaking of the torroids can offer slight changes.

20M2.32 watts
17M2.31 watts
15M3.45 watts
12M2.69 watts
10M3.65 watts

Filed Under: (tr)uSDX, POTA, radio

Noise in the attic?

February 17, 2024 by Bob Easton Leave a Comment

If you have been following along with my antenna experiments, you know that I always work with temporary outdoor / field antennas and have been searching for a solution I can make more permanent. It needs to be always available, and frequency resilient.

The idea that I’ve harbored for a long time is a multi-band antenna in the attic. Never mind that certain people don’t want me climbing around in an attic which is likely more complex than the simple one we had “up north.”

The very successful EFHW became the ideal candidate. It performs well, even if its signal strength is about 1/2 an S-unit lower than my best verticals. I remade the original with heavier, more durable, wire and field tested it several days. Like the original, it performed well, with no need of a tuner, on 40M, 20M, 15m, and 10m. All I needed was someone to hang it in the attic.

After a good bit of searching, a good guy known as “The Village Tinker” suggested a certain “low voltage” installation firm (cable TV, ethernet, etc. ) They agreed to do it for the simple price of a one hour service call. A couple of guys came out and I described what I wanted, emphasizing that as high as possible was my desire. I handed them the antenna, complete with the 49:1 transformer in a box, and a simple center hanger that I had been using outdoors. They had the job done in about an hour and we exchanged a check for a receipt.

Results: the 4 band antenna that needed no tuner is now a 4 band antenna that needs a tuner for 3 of those bands, doesn’t hear very well, and has an S-5 noise floor! Sigh!!! I have made a few QSOs with it. The signal reports are lower than with other antennas, and the noise, apparently from other things running through the attic, makes it uncomfortable for listening and decoding CW. It certainly will not be an everyday antenna, maybe an alternative on rainy days.

40M every day use, needs a tuner.
15M needs a tuner
10M needs a tuner
20M every day use – NO tuner needed

What happened? I asked one of the installers to show me, on a overhead picture of the house, where the antenna ended up. It wasn’t as high as I expected, nor did it run quite as I expected. By that time, we were out of service call time, and I didn’t ask that he go change anything. What had really happened? He put the center hanger, a simple little plastic triangle with a few holes, as high as he could (not very)… when he came to it … If were installing it, I would have scooted the hanger along until I could get it up to the peak of the roof line. Because he didn’t use some of the distance going up, he had more wire left at the far end, and simply routed it around a corner. The antenna is not the inverted vee I wanted, but a bent horizontal that’s not very high. That speaks to the “doesn’t hear well” aspect. The difference in resonance points and in ambient noise floor is most likely due to the nearness of all the other kinds of wires and ducts in the attic space.

Should I ask for another service call to relocate it up to the top of the roof line? With the unpleasantly high noise floor, I think not.

Filed Under: antennas

Yet Another EFHW Experiment

February 13, 2024 by Bob Easton Leave a Comment

Bottom line: It is a reasonable 3.5 band antenna. It resonates OK on 40M, very well on 20M, OK on 15M, and can be coerced for 18M, and NO-GO on all other bands.

The design is found in an article that I have since lost (nobody specific to blame) and is based on making an End Fed Half Wave that is like many of the 40/20/15/10 designs but is made shorter by using an R/C network part way along the length. I don’t know the precise length and am too lazy to unwind and measure it. I’ll do that someday when I want to recycle the wire. ๐Ÿ™‚ My adjustment to the design was in winding the 36:1 transformer on a core different from the usual larger core. Colin, MM0OPX purports this core to work better for frequencies above 20 Mhz. In reality, it didn’t work out that way for me. I also put some effort into packaging the transformer and BNC connector into a small streamlined form.

I launched it in the backyard in the usual inverted vee fashion of some of my other wires. Measurements with a NanoVNA produced these SWR values:

Band

40M

20M

15M

10M

Best Freq

7.26

13.9

21.13

28.45

Best SWR

1.35

1.05

1.57

2.65

QRP Freq

7.06

14.06

21.06

28.06

SWR

1.69

1.35

1.62

3.3

It becomes yet another addition to my antenna graveyard / spare parts bin.

Filed Under: antennas

EFHW SUCCESS!

January 15, 2024 by Bob Easton Leave a Comment

This follows the EFHW Fail article. There are a lot of ways to configure an End Fed Half Wave antenna. The earlier article explored a variant that sort of works, but not as well as expected … and certainly not as well as this one.

This EFHW variant is very common, a 49:1 transformer, bridged with a 100pf capacitor, and about 67 feet of wire. It is designed for 40M and higher. Once assembled, the wire is cut to a length that produces the desired resonance points, and there are several with this design.

About design… There’s a well known chart for Random Wire Antenna Lengths. It shows all sorts of lengths to use for antennas that are (1) random length, (2) are not resident on any band, and (3) always require the use of an antenna tuner. There must be some good rationale for such a thing, but it befuddles me why anyone intentionally always wants to use part of their RF output to warm up coils in a tuner. Aren’t antennas resonant at the desired frequencies a lot more efficient? OK, let’s set that aside… the chart is also, maybe unintentionally, helpful for offering the good lengths for EFHW antennas that have multiple natural resonance points. Just use the parts of the chart marked in red that the chart labels “Lengths to avoid.” They are EXACTLY the ones we want.

That blue oval is my addition to the chart, and the starting point for this antenna’s length. The actual length, trimmed as I like it, is 66 feet, 5 inches.

The design is so popular that a number of hams sell kits for building a 40m version. These are the people willing to gather all the parts, package them nicely for us, and save us the effort of finding each individual piece. Just try buying one BNC connector and paying shipping for it, then the wire, then the capacitor, then the torroid, etc. etc. One of those kit packagers is Jason Oleham, KM4ACK. His kit sells for about $40 and is often out of stock because of its popularity. The KM4ACK EFHW kit was the starting point for my EFHW adventures. It worked better than many other wire antennas I experimented with over the past year. As advertised, it is naturally resonant on 40M, 20M, 15M and 10M. With careful trimming, I made mine happy to work very well in the CW portions of those bands. BTW, it works with NO counterpoise, and is not sensitive to feedline length.

After testing the KM4ACK EFHW, I tried other EFHW variations and came back to the KM4ACK as “the winner.” My goal is to use it as a permanent antenna in the attic. I have repackaged it into a small plastic box that’s more appropriate for hanging in the attic. I also changed the wire from very lightweight 18 AWG, very nice for portable ops, to more durable 22 AWG.

My test setup is an inverted vee in the backyard. That’s about the shape it will have with optimum placement in the attic. Outside, I support it with a 17 foot collapsible fiberglass mast. As tested, the ends are only about 18 inches above ground, something that will be 8 or 9 feet higher in the attic.

Below are NanoVNA screenshots for 3-20Mhz, 40M, 20M, 15M and 10M. In all the charts, the marker shows the QRP hailing frequency in the CW portion of the band.

Interestingly, the tuner built into the Penntek TR-45L can tune this antenna on 80M and 30M, but definitely not on 17M. I haven’t actually made contacts with the tuned results on 80M and 30M, but have on the other bands. I’m very pleased with the results, a good step toward frequency resilience for this HOA ham. Next, let’s see what it does when placed under roof.

Under roof update: My original idea was to use this successful antenna as an indoors antenna, in the attic space of our home. That didn’t work out so well. Due to a local prohibition against wandering around in the attic, I hired a wiring firm to do the job. With little antenna experience they installed it, but not as high as I wanted, and “folded” into a tortuous path. It’s a failure in any but the last-chance alternative.

Next, let’s look at a couple of WSPR runs for the bands I use most, 20M and 40M. I’ll get to WSPR runs for the other bands soon. In the meantime, I’ll mention that my first contacts on 15M and 10M with this antenna were TX and AZ.

Filed Under: antennas

EFHW Fail

January 12, 2024 by Bob Easton Leave a Comment

Living in an HOA area, my constant quest is for a stealthy, multiband, effective antenna. When I arrive at a good one, I plan to install it in the attic. That installation will reduce the everyday setup and teardown of the “backyard” portable antennas. Over the past year, I’ve tried many antennas and my antenna junk box is full of “spare parts.” I added more to the pile yesterday. It actually is a workable antenna, but one that fails to be as good as others, and fails to meet my expectations.

The antenna is an EFHW that I found in an issue of CQ magazine from several years ago. I won’t be more specific, because I don’t want to cast blame. The thing might work very well for someone else. Like all EFHW designs, this one is a transformer and a wire. The transformer is 36:1, the wire about 65 feet (later cut to trim for 20M), and has an RC network about 1/3 of the way along the length.

My test rig for such an antenna is putting it up in an inverted vee form using a 17 foot collapsible mast as the center support. That form sort of mimics the roofline of the house, for when I move it into the attic. Measurements are made with a NanoVNA.

My expectations are for multiband: at least the CW portions of 40M and 20M, others if I can get them, and SWR low enough that I can run the TR-45L transceiver without engaging its tuner. This antenna got me the first part, resonance at 7.040 and 14.040 (blue trace), acceptable impedance, but with SWRs too high for my liking.

There’s another EFHW that does better. We’ll see it shortly…

Filed Under: antennas

An Uncomfortable QSO

January 11, 2024 by Bob Easton Leave a Comment

Those who have tripped across my QRZ page know that my primary interests are QRP, CW and POTA (Parks On The Air). It’s also true that I’m in perpetual CW rehab, which is coming along more slowly than I would like. Some of that might be due to my addiction as a POTA hunter. For an old ham returning to the hobby after a 30+ year lapse, and trying to relearn CW the right way, POTA is an easy entry point. The protocol for POTA is very simple (I need simple) and brief. It is almost spoils one because the 2 most important things one need listen for is their own callsign and a signal report. Know when someone is answering you and know that right after the signal report it’s your turn to send the expected reply. The good news is that I’ve become comfortable with POTA to the tune of about 1200 QSOs over the past 6 months. The bad news is that my CW comprehension is slowly improving, but not as much as I would like.

A while ago I made a determination to do 2 things (1) break out of my “POTA plateau” into other types of CW exchanges, and (2) apply to get into a CWInnovations class. Both were involved in a strange QSO I had today.

There weren’t many activators in parks today, and after I worked all that I could hear, I wandered around looking for other activity. I heard K3Y/4 on 20M at about 21:00z this afternoon, and answered. I foolishly answered in POTA style with only my callsign and was pleasantly surprised to hear a return. That’s where “pleasant” ended. I suddenly realized “Ohhhhh, this is a special events station… and I don’t know the protocol.” The response was coming quickly now (did I mention I need comprehension improvement?) It slowly sank in that K3Y was part of the month long event for the Straight Key Century Club, SKCC. … and my cheat sheet for SKCC exchanges wasn’t within reach. I fumbled terribly through QTH and RST information and then heard the respondent send a string of numbers (among other stuff that I missed). Numbers? Oh yeah; that must be their SKCC membership number. I have one of those, remembered it, and sent it off. We managed to close the QSO peacefully, but I thought it a very ragged mess on my part. I missed a lot, and fumbled a lot.

OK. So, who was that person behind the K3Y/4 callsign? Digging around enough in the K3Y website one can find a schedule of operators for the event. Hmmmm, let’s see… 20:00z to 22:00z on Jan 10 K3Y/4 is operated by K04WFP, Teri Beard. YIKES!!! Teri is one of my CW coaches on an upcoming CWInnovations class.

Great goin’ Bob, what a way to have a first QSO with a future coach!

I should also note that I violated one of my own practices. I failed to listen first, to get an idea from the previous QSOs of how they go. Many say part of learning is being uncomfortable. Been there, done that.

Filed Under: CWI, POTA, SKCC

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