Many thanks to Joshua (KO4AWH) who shares the following guest post:
Unun Insertion Loss (Efficiency) Testing
by Joshua (KO4AWH)
A simple “side-by-side’ method can be deployed with the use of a Calibrated NanoVNA to read back “S21 Gain” which is, in this case, signal loss from the output of S11 back into S21 through the identical windings. The gain (loss) reading in negative dB gives us the total signal loss through the windings. We can then divide by 2 to get the loss through one winding and then convert with a bit of math to an efficiency number.
p = 10^(x/10) * 100 where p = percentage 0-100% and x = loss in dB
Example: -2dB reading on “S21 Gain” on the NanoVNA divide by 2 for a loss of -1dB on each winding would be 10^(-1/10) * 100 = 79.4%
We have a 50 ohm signal coming out on S11 of the NanoVNA through the first winding to some unknown exact impedance but that is then converted back through the second unun into the S21 port where the signal is measured. It is therefore necessary to use identical windings for each test to ideally match the impedance change.
I like to run the signal test with the top and bottom of each band, take the average of the two, and then convert to efficiency, 100% being perfect. I record these values to then chart each band’s efficiency for the winding pairs. The goal here is to compare the different windings. For example, with a 9:1 used for a long/random wire, compare toroid sizes, number of toroids and in some cases the number of windings. One nice advantage to a 9:1 Trifilar winding is that you can increase or decrease the winding count in multiples of 3 while maintaining a 3:1 winding ratio. Take the square of the windings ratio (3) to find the impedance ratio of 9:1.
Here is one example of two different windings compared. Both are Trifilar but one with a single T80-2 toroid and 9 sets of turns and the second with a Double T80-2 and 12 sets of turns. 100% would be zero signal loss through the windings, 0% would be full signal loss. -3dB (loss) per winding would equate to a 50% efficiency in either single winding.
The difference between these two windings across the Amature Bands was quite surprising to me. I assume typical, often used windings will be decent across the bands. Here we saw a large improvement in access to the bands by adding several extra turns.
When each component of the station induces loss to the radiated signal, or the ability to receive, you have to improve each area for the best transmit and receive capability. This test is not foolproof, it is not the most accurate way to measure efficiency and maybe not the easiest but it gives me a comparative analysis of various windings with the tools available to me. If I can increase the performance of my windings, I can increase the performance of my station. Time to wind some more transformers!
To date, I believe I’ve activated 11 parks (1 in Ontario, 10 in Québec) during our extended family vacation. Instead of hitting the same parks over and over, I’m trying to activate new parks during each outing because it’s giving us an opportunity to explore some really amazing spots that we might not otherwise discover.
Camping on the North Coast of the St. Lawrence in Bon Désir.
Before we leave La Belle Province, I’ve at least two SOTA summits in mind and 3-4 more parks, family time permitting. Indeed, as I mention below, I hope to activate another park sometime today.
Ham Radio Workbench Podcast
Once again the fine crew of the Ham Radio Workbench Podcast made the mistake of inviting me on another episode of the podcast.
In truth, it’s a proper honor to join them each time (don’t let them know I said that!). Seriously, they’re an amazing group of friends.
This episode was dedicated to our Field Day activities. For many of us, it was an unconventional Field Day and perhaps that’s what made the event so much fun.
John (W7DBO) was invited back to the show and it was great hearing how he integrated his whole family in his Field Day activities.
George had to operate from home, I operated from our condo/chalet here in Québec, and Vince from his very unique club setup in Alberta. Rob had a project that took priority on Field Day, and it’s worth listening to the podcast just to hear Smitty’s tale of life as a Field Day RVer (hint: not for the faint of heart).
I did finally choose that one extra radio: the Discovery TX-500.
I chose the TX-500 because 1.) it would be a great “bad weather” radio, 2.) it could operate from my KX2 battery packs, 3.) it’s multimode and also covers 6 meters, and 4.) it has such a slim profile. I could easily the TX-500 in my Tom Bihn Synapse 25 backpack with the Elecraft KX2 and it didn’t make the pack feel any bulkier.
I came very close to choosing the IC-705, but it was just a bit too bulky for the way I had my pack configured.
Back to the hypocrite part…
The day before leaving North Carolina, I removed everything from our Subaru and gave it a deep cleaning.
When I pulled up the floor panel in the trunk/boot area to check the first aid kit, spare tire, and emergency gear I discovered that there was a fairly large unused area under there–a spot where I might be able to sneak a few extra radio supplies.
After a little finagling, I discovered that I could fit spare batteries, two folding PowerFilm panels, the Buddipole PowerMini 2, and two more radios: the MTR-3B field kit, and my Elecraft KX1.
This essentially amounted to contraband since I tend to be the guy who enforces “one bag per person” policy during our family travels.
I got some serious eye rolls from the family when they discovered the hidden radios after we reached our destination. I might not ever live this down.
If I had even a shred of dignity upon our arrival here in Canada, I can confirm it’s gone now.
Elecraft KX2 getting heavy use
Other than Field Day where I primarily used the TX-500, the Elecraft KX2 has been getting a heavy workout on this trip.
The reason why is because I’ve been activating a number of urban parks where an all-in one radio paired with a random wire or the AX1 vertical has been very useful.
Conditions have been very rough during some of these activations as well, so it’s nice to have both CW and SSB modes available and a full 5 watts (the KX1 and MTR-3B are CW-only hover around 3 watts). I’ve snagged some excellent QRP DX at times, but everything has been so unstable.
I didn’t bring the KX2 hand mic on this trip, so all of my SSB contacts have utilized the KX2’s built-in mic. It’s actually worked brilliantly!
I’ve recorded a number of activations here in Canada and will likely post a couple of these out of chronological order while I’m still on this side of the border.
Uploading from our chalet hasn’t been possible–the upload speeds are about as dismal as they are at my QTH. Download isn’t too bad, though.
Hôtel Le Manoir, Baie-Comeau
While at the hotel in Baie-Comeau a few days ago, I uploaded at least four videos with their high-speed internet, so I’ll soon post a couple of them.
In short: the activations here have been amazingly fun. Some of the sites have been truly spectacular in terms of scenery and others are in urban settings taking me well outside my comfort zone.
In short: I’ve loved every minute of it!
Travels
Photo by K4TLI
We have had an amazing time here in Québec as always.
Our flavor of travel is the opposite of many: we tend to rent a home or apartment for a few weeks or couple of months and use it as a base for exploring the region. We do this as opposed to traveling long distances and only spending relatively short periods of time at multiple stops.
Activation today
I plan to activate a park while in Québec City today. I’ve no clue which one it’ll be yet, but I’ll announce it on the POTA site once I’ve got a plan together. If you have the time, look for me on the POTA spots page (as VY2SW) or via the RBN! I’d love to put you in the logs.
Here’s wishing all of you a week full of radio and fun!
Many thanks to Paul (W0RW) who shares the following guest post:
Operating in St. Elmo Ghost Town, Colorado
by Paul (W0RW)
I have operated in St Elmo (Ghost Town) several times with my PRC319 Pedestrian Mobile. St. Elmo is at 11,000 feet in a deep canyon so it was hard to make contacts.
My PRC319 runs 50 Watts and I use a 10 foot whip so I had some success to the East on CW. I use a Whiterook MK-33 for a hand held single lever paddle.
OLYMPUS DIGITAL CAMERA
Right after my last visit, July 2015, members of St. Elmo and Chalk Creek Canyon Historical group cleaned out the outhouse behind the Home Comfort Hotel in St. Elmo, they found a potentially explosive surprise. On the floor of the outhouse, they found what they believed to be dynamite. Later in the day the bomb squad found blasting caps rather than dynamite.
St Elmo Outhouse
[Per the Historical Society] there were only 6 Blasting Caps found at St Elmo’s. They called Ft. Carson US Army EOD and they blew them up right there in the center of town.
While the electric blasting caps are usually shorted and would not be effected by a QRP radio, my 50W radio was at a dangerously high level to be transmitting near a box of blasting caps.
It would be a smart idea to avoid operating in any old mining areas where unexploded dynamite might exist.
At least ninety percentof all of my radio operations happen in the field. Whether I’m in a park, on a summit activation, or I’m out camping, I’ve always thoroughly enjoyed “playing radio” outdoors. In fact, it was the joy of field radio––and the accompanying challenge of low-power operations––which launched my labor of love in the world of ham radio.
I’ve been running QRPer.com now for fourteen years, and during that time, the questions I’m asked most deal with selecting a field radio. Turns out, it’s an incredibly difficult question to answer, and we’ll touch on why that is before we dive into the reasons one radio might hold appeal over another for you.
Instead of offering up a list of field radios on the market, and reviewing each one—and, to be fair, there are so many these days—I’ll share with you a series of questions you might ask yourself before making a radio purchase, and follow up with a few bits of advice based on my own experience.These deceptively simple questions will help hone your decision-making. Finally, I’ll note a few of my favorite general coverage field radios and share what I love about each.
But, first…
Spoiler alert: It’s all about the operator, less about the specs
When searching for a new radio, we hams tend to take deep dives into feature and specification comparisons between various models of radios. We’ll reference Rob Sherwood’s superb receiver test data table, we’ll pour over user reviews, and we’ll download full radio manuals before we choose.
While this is valuable information—especially since radios can be quite a costly “investment”—I would argue that this process shouldn’t be your first step.
I’ve found that enjoyment of any particular radio—whether field radio or not—has everything to do with the operator and less to do with the radio’s actual performance.
A realistic assessment of yourself
The first step in choosing a field radio is to ask yourself a few questions, and answer them as honestly as you can. Here are some basic questions to get you started in your search of a field radio:
Question 1: Where do I plan to operate?
If you plan to operate mostly at the QTH or indoors with only the occasional foray outdoors, you may want a field-capable radio that best suits you indoors—one with robust audio, a larger encoder, a larger display, and more front panel real estate.
On the other hand, if you plan to take your radio on backpacking adventures, then portability, battery efficiency and durability are king
Of course, most of us may be somewhere in between, having park activations or camping trips in mind, but overall size may be less important as we may be driving or taking only a short walk to the activation site. When your shack is a picnic table not too far from a parking lot or even an RV, you have a lot more options than when you have to hike up a mountain with your radio gear in tow.
Question 2: What modes will I operate the most?
Are you a single mode operator? If your intention is to only use digital modes, then you’ll want a radio designed with easy digital mode operation in mind.
If you plan to focus on single sideband, power output may be more important and features like voice-memory keying.
If you plan to primarily operate CW, then the radio world is your oyster because it even opens the door to numerous inexpensive CW-only field radios.
If you plan to primarily operate CW, I would strongly suggest going low power or QRP. I’ve often heard that 5 watts CW is roughly equivalent to 80 watts single sideband. I tend to agree with this. CW field operators hardly need more than 5 watts, in my experience.
Many thanks to Scott (KK4Z) who shares the following post from his blog KK4Z.com:
QRO SCHMURO
There is always a lot of talk about QRP vs QRO, 5 watts vs 10, ad nauseam. So today I thought I would run the numbers and see what the real deal is. First we need a few definitions. An S-unit in general terms is the minimum change in signal strength to be just noticeable (k3wwp.com). In more technical terms it equates to approximately 6 db in change. The decibel (dB) is a logarithmic number. Each 10 dB represents a factor of 10 difference. This may be a little out there for some so we will cut right to the shortcut. There are two types of logarithms. For calculating dB, use the common logarithm which is base 10. To see if your calculator uses the right one. Punch in 100 and then log. The answer should be 2 which equates to 10 to the second power which equals 100. This is not a technical paper but an entry way to see how changing the power levels affect the signal level of your transmitting signal. As you guessed, it is not linear.
Let me introduce an equation:
Where Power P1 is the power you wish to evaluate and reference power P2 is your starting power. Let’s take going from 5 watts to 10 watts. The equation would look like this:
We take 10 and divide it by 5 which give us 2. Then we hit the log function on our calculator which gives us 0.301. Multiply that by 10 and you have about 3 dB in gain or about one half of an S-unit (remember 1 S-unit is equal to 6 dB). Let’s do one more by hand and tackle the QRP/QRO debate. How many S-units will increasing power from 5 watts to 100 watts give you? The equation looks like this:
Take the 100 and divide by 5 to give you 20 and then hit the log function to give you 1.301. Multiply by 10 for 13.01 dB. Divide 13.01 by 6 dB and you have 2.17 S-units. Going back to our definition that one S-unit is the minimum change in signal strength to be just noticeable shows that going from 5 watts to 100 watts is not that great of a change.
Let’s let the other shoe drop. What about going from 5 watts to 1500 watt? That will give you 4.13 S-units of gain vs 1.96 S-units going from 100 watts to 1500 watts?
This gives you a fairly easy equation to help you evaluate your needs based upon empirical data. Running 20 watts over 5 gives you 1 S-Unit. Using less power means less drain on the battery for longer operation. This is only part of the equation. Propagation, antenna, mode used, and station efficiency all play a part. Have fun and maybe don’t toss the QRP radio yet.
Many thanks to Scott (KK4Z) who shares the following project from his blog KK4Z.com:
Paddle Mount for the IC-705
I kinda like the idea of being able to mount your paddle to your radio when operating portable. You can use the weight of the radio to help prevent the paddles from moving around and it frees your off hand for other tasks. We see examples of this with the Elecraft KX series of radios and there are some adapters for radios such as the Yaesu Ft-817/818.
I really like my IC-705. It is probably my best radio for POTA/potable operation. I think the only time I would leave it home is if weight became a problem or I needed to exercise one of my other radios. Recently, Begali came out with a mount to attach their Adventure paddle to the IC-705. It is a sweet set-up; however, the approx. $400 USD price tag got me looking for other alternatives. I have nothing against Begali, I own three of their paddles, and they are superb instruments. I think I wanted to tinker, and this gave me a good excuse.
For paddles, I have a set of Larry’s (N0SA) SOTA paddles. I love these paddles. When I go on an activation/Portable Operation, I bring these and my Begali Travelers. If I was going to do a SOTA activation, I would just bring Larry’s Paddles. Next was a trip to Tractor Supply Company (TSC) for a sheet of 16 ga. Steel. That set me back $16. I cut it to 3″ by 3 1/2″ using a cutoff wheel on my grinder.
I already have a stand I made out of 1″ x 1″ angle aluminum so I cut this to fit behind it.
The blue on the metal is Dykem Blue which is a layout fluid. In creating this project, I am only using hand tools. Power tools consisted of a grinder with a cut-off wheel. a hand drill, and my trusty Dremel tool. Here is a picture of me giving the mount a rough finish with a file. Continue reading Scott Builds a clever Icom IC-705 Paddle Mount→
“Look at this, Tom! Only the stuff I need and nothing more,” cheerfully noted my good friend and Elmer, Mike (K8RAT). It was Field Day two decades ago, and Mike was gazing at his TEN-TEC Scout. I glanced over, and agreed. “So simple and so effective,” Mike added.
I’ve never forgotten Mike’s sage words. That Scout (Model 555) was about as simple as a then-modern HF transceiver could be: it had a total of three knobs––one for AF gain and IF bandwidth, one for RIT and Mic gain, and an encoder. It also had three mechanical switches on the front: one for power, one for TUNE and NB, and one for CW speed and RIT. It also had an analog SWR/power meter. The Scout used plug-in band modules for each HF band and featured a large segmented bright green LED frequency display that was characteristic of so many TEN-TEC rigs of the day.
And Mike was right. For those of us who appreciate radios with a simple, uncluttered, and an almost utilitarian interface, the Scout was, in vintage parlance, “the bee’s knees.” And that the Scout also performed beautifully was just icing on that cake.
When the Scout first appeared in 1994, embedded menu options and spectrum displays were not yet commonplace among amateur transceivers. Embedded menu items can open the door to near granular level control of your radio’s functionality and features. Then again, if those embedded menus aren’t well thought out, it can lead to awkward operation practices in the field, during a contest, or even during casual operation.
As a radio reviewer, I spend a great deal of time sorting out embedded menu functionality and design. Perhaps it’s for this reason that I so enjoyed reviewing a radio that bucks this trend and reminds me of a time that was simpler, not to mention, easier.
All of his transceiver kits are available at his website WA3RNC.com.
I was first drawn to the TR-35 after reading the opening paragraph of the product description:
“Compact but powerful 4-band, 5-watt CW transceiver kit that uses no tiny push buttons, and without those seemingly endless and hard-to-remember back menus. There is a knob or a switch for every function!”
Sold!
I considered buying and building the TR-35 kit, but I wanted my eventual review––this one!––to focus on the radio’s functionality and performance. So a factory-assembled and tested unit was right for this purpose, just so that any performance issues wouldn’t be a result of any shortcomings in my kit building skills.
Many thanks to John (VE3IPS) who shares the following guest post:
Nova Scotia POTA After-Action Report
by John VE3IPS
We had planned a vacation trip out to Nova Scotia to get our lobster fix. As I always do, I prep my radio with local repeaters, look up local radio clubs, museums and check the POTA and SOTA map for locations to operate from.
I noticed that several park locations had not been activated. Thus I had an opportunity to be first activator and to get some much needed Nova Scotia parks in the Hunters logs. I printed the map and noted the park identifiers. I decided to just activate the parks that were never activated. I could have worked more parks but you have sights to see and can’t be behind the mic all the time. My antenna was prepped to be rapidly deployed in a few minutes and torn down accordingly.
I also was able to attend the Halifax ARC Hamfest on June 4, 2022.
So a vacation with ham radio elements to keep me excited with some objectives in mind.
We did visit Peggy’s Cove, Burnt Coat Head to watch the tides in the Bay of Fundy, local wineries, Lunenburg (a movie shoot was underway), the Halifax Citadel and of course eat lobster every day. I spent over $200 in gas as we did a lot of driving around (gas is just over $8 a gallon CAD), retail tax at 15% and prices for food and restaurants up by 30%. Nova Scotia is a bit more expensive than other cities.
I decided to bring my Icom 705 with a LifePO4 battery to offer 10 watts instead of the FT-891 or FT-818. Why? Because it offered a voice memory for calling CQ Parks, built in SWR meter and better IF filters over the FT-818. I wanted to cover the Marine and VHF/UHF repeaters as well and that ruled out the FT-891.
Due to the Kleenex box form factor I ended up using a Lowe Pro Omni Trekker camera bag to use as a carry on. This included a Nikon V1 camera and Binoculars.
I am a subscriber and ham radio operator circa 1974. Like you (and a lotta hams) I started as a SWL using a transistorized Lafayette Radio receiver.
Last evening, I listened to the April 2022 Wireless Flirt podcast from Ireland where you were interviewed about the comeback of SW radio. Well done Thomas! You are one articulate dude!
I currently have a uBitx that I use for base and portable operation. We share an interest in POTA and other QRP field operations.
My latest obsession is WSPR. Attached [linked below], please find some of my WSPR findings on 40 meters.
Thank you so much for sharing this and for the kind words, Jim! It’s strange, but I’ve yet to dive into the world of WSPR. I actually have a QRPLabs QCX+ transceiver kit I purchased specifically to explore WSPR. I just need to find the time to build it now!
Many thanks to Pat (N0HR) who shared following question in a comment:
Thomas
I simply love your videos – both your impressions of the gear and the activations themselves. Great stuff.
I’m curious – now that you’ve played with both the SW-3B and the Penntek TR-35, which is the favorite? Seems like they’re both roughly in the same price range.
Thanks for your fantastic channel and website
73, Pat N0HR
Thank you for the kind words, Pat, and great question! Several people have asked me variations of this very question recently.
I like both radios, so I’ll frame this in a way that might help others make a purchase decision.
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