Tag Archives: Joshua (KO4AWH)

Field Report: QRP SOTA and POTA on Big Cedar and Black Mountain in North Georgia

As I mentioned in a previous post, I attended the W4G SOTA Fall Campout in October and it was nothing short of amazing.

It was so great to spend an extended weekend camping, hiking, and hopping on the air with other SOTA activators.

I especially enjoyed getting to know Joshua (KO4AWH)–the fellow behind Tufteln products— over that weekend. He needed a campsite and since my buddy Monty had to pull out of the trip due family activities, I was happy to share the tent site with him.  It actually worked out quite well since we could then pair up and car pool to our SOTA and POTA activations.

What follows is a field report for two SOTA activations Joshua and I did back-to-back on Friday, October 14, 2022.

The trail head for both of these summits was only a few miles from our campsite at Lake Winfield Scott.


Note that I used the same gear during both SOTA activations all packed in my Spec-Ops Brand SOTA backpack.

Black Mountain and Big Cedar essentially share the same trailhead at the Woody Gap Recreational Area parking lot on Highway 60.

We were on site early enough to grab a parking space. Keep in mind that it was Friday during leaf season, so there were quite a few hikers on the trails that day! In fact, by midday, the parking lot was overflowing with cars.

Almost by flip of coin, we decided to hit Big Cedar Mountain first. Turns out, Joshua had actually hiked to this summit in the past and even met a SOTA activator en route (and I believe this might have been his inspiration to try Summits On The Air!).

Big Cedar Mountain (W4G/NG-023)

The 1.1 mile hike to the summit of Big Cedar Mountain was brilliant and the views were absolutely stunning. Continue reading Field Report: QRP SOTA and POTA on Big Cedar and Black Mountain in North Georgia

Guest Post: Breaking 100 QSOs during two QRP SSB Activations

Breaking 100 QSOs during two QRP SSB Activations

by Joshua (KO4AWH)

Back in May I had to travel last minute for work to North Dakota. I typically bring radio gear in the event that I have some time to do a Parks On the Air activation. This trip presented the opportunity to activate a park in Minnesota as well as one in South Dakota. I didn’t have much time to plan these activations, but I knew I had an early enough arrival in the afternoon that I could likely activate a park in MN and then in SD. So, I picked out a park in MN close to my destination. I could go activate in MN then get over to a park in SD and activate there.

I found a nice looking State Park in MN. The idea was to activate as quickly as I could and then get back to a park in ND with enough time to activate before it got too late. K-2482 Fort Snelling State Park had 110 successful activations. That is always promising when planning out an activation. I got my rental car and headed to the park.

I also had recently purchased a HFJ-350m which is a base-loaded coil with an extendable whip. I found a tripod base I could print online and then designed an adapter so I could install a SO-239 and RG316 lead with a BNC connector. I had just tested this setup in the back yard and knew it worked, although I certainly knew it was a compromised antenna.

HFJ-350m setup on custom tripod in the backyard for testing
Custom 3D Printed Tripod with BNC Connector

I typically bring my Raspberry PI4 loaded with Build-A-Pi and then run digital modes from my phone or Tablet. My plan was to activate this park with the compromised antenna running 5W on FT8 at the first park and then go to my second park and run a full half wave wire in a tree on SSB at 10W.

Not much to say about the activation in MN. The state park was nice but where I set up presented quite a bit of RF noise. Not so much of a problem since I was running digital. After a bit of adjustment on the whip I was tuned for 20m and started hunting a few FT8 stations. I did make a few QSOs while hunting but I then started calling CQ and had a bit more luck. I think because my signal was quite weak, calling CQ was a bit more efficient as only those who could hear me were calling back. While hunting, if those calling CQ were running a bit more power, I was unlikely to get in while running lower power and on a compromised antenna. I got the activation completed with 12 QSOs and packed it up and headed to the next park.

Continue reading Guest Post: Breaking 100 QSOs during two QRP SSB Activations

W4G SOTA Fall Campout Recap

As I noted last week, I participated in the W4G SOTA campout at Lake Winfield-Scott Campground in the Chattahoochee-Oconee National Forest in north Georgia.

In short? It was amazing!

I thought I’d share a few photos and memories…

Campsite and friends

These SOTA campouts typically involve an announcement via the W4 SOTA group then we all make individual reservations at the chosen campground. Since we’re not reserving the whole campground as a block, we tend to share our individual camping sites with others who might not have been able to reserve a spot.

At Lake Windfield Scott campground, the SOTA group did reserve one large group campsite, but only a couple months ago it was canceled by the park service due to a trail maintenance group that needed it.

Typically, I camp with my friend Monty, but he had other family plans that weekend.

When I found out my buddy Joshua (KO4AWH)–the fellow behind Tufteln products–needed a spot to pitch his tent, I offered up my site.

As you can see in the photo above, both of our tents fit on the tent pad with absolutely no extra room to spare. 🙂

It was such a pleasure getting to know Joshua. What a kindred spirit and super nice fellow.

KO4AWH (left) and K4SWL (right) on the summit of Black Mountain.

We ended up doing all of our SOTA activations together as you will see in upcoming activation videos and field reports.

Joshua is as pack and organization obsessed as I am. A proper pack nerd! I really enjoyed checking out his bags, cases and all of the brilliant accessories that are a part of his field kits.

He brought both an IC-705 and TX-500 along for the ride. He logs in the field using the HAMRS app (same one I do) but on an iPad Mini (see photo above) and I must admit that the size of the iPad mini is nearly ideal–much better than a phone for logging.

He also used the SDR-Control app to connect wirelessly with his IC-705 and operate digital modes.


We activated a total of three summits during the weekend (Big Cedar, Black Mountain, and Yonah Mountain). It would have been easy to activate six or more if that was the goal–the area is chock full of accessible summits.

Continue reading W4G SOTA Fall Campout Recap

Joshua acquires an Argonaut 509

Many thanks to Joshua (KO4AWH) who shares the following guest post:

Ten-Tec Argonaut 509 Acquisition

by Joshua (KO4AWH)

My club president sent me a text on Sunday before our Monday club meeting. He wanted to know if I was interested in a Vintage 80s QRP Radio. He knows I have an affinity for QRP. Honestly, I think he is still amazed at how I managed to get through piles ups on his hexbeam during summer field day with my TX-500. Boy was that fun.

The deal was a Ten-Tec 509 with the microphone and CW filter, the matching 251 power supply with meter, and the 504 matching 50W amplifier. He sent me a photo, I had to look it up. I have heard of Ten-Tec, thanks to Thomas K4SWL, but certainly was not familiar with their Argonaut 509. I was intrigued. I don’t have a single vintage piece of equipment. I have only been a Ham for less than 3 years.

We had some equipment from a club member SK donated for auction to raise funds for some club repeater upgrades. This was a good excuse to purchase an old piece of equipment that I likely would not have purchased otherwise. After looking over the 509 and accessories, all of which were in great condition, I brought them home. Of course I couldn’t help but hook everything up and turn on power. Everything powered up but no movement of the frequency indicator, not a great sign, and no audible hint of changing reception frequency. After further inspection it seemed the dial tuning mechanism was seized up. Looks like another project.

The next morning, as I had a few minutes to spare I started taking things apart. I have never pulled apart an old transmitter before so I took my time as I studied all the components and marveled at the simplistic yet complex circuitry found under the covers. Once I was down to the tuning mechanism, a few desoldered wires later, it was removed and ready for cleaning. I don’t know if the grease was original, but it sure was hard. After carefully cleaning, greasing, and reassembling all the components, soldering a couple wires back, and reassembling the housing, I was ready to power it back up. I don’t want to understate the work involved, it can be quite tricky, but I really enjoy this type of thing.

After tuning around a bit and working with the controls on the Radio, I found a POTA operator to zero beat. I needed something to reference in order to adjust my knob indicator so I would know what frequency the radio is on. I actually received the manual for the radio and each of the components. Reading through a few key points the night before really helped out when I was ready to start tuning in and transmitting.

I had the amplifier on, I set the DRIVE to about half way guessing that was okay and called back to the Activator. First call, he called me back with a 59! WOW, I was excited. I let him know I was on an old Ten-Tec that I had just repaired and he came back and said the audio and signal were great. How exciting! So, naturally, I hunted a few more stations and then listened to a few rag chews as I got familiar with the Radio.

Not only was I excited to have repaired my first radio, I am also amazed at the capability of this Radio originally released in 1973. I am not a long time SWL or radio operator but there is certainly something very appealing to me about the audio this Rig produces. I wasn’t certain what I was getting into with this rig, but I sure am happy how it worked out! I may just be on the hunt for another Ten-Tec. I even plan to take this to my local park and do at least one activation with it.

Here is a quick excerpt from the introduction in the operating manual.

“The Argonaut opens a whole new world of excitement and fun in Amateur Radio. We think you will find QRP a welcome change. Five watts are only 2-1/2 S-units below 150 watts for the same conditions. When skip is favorable and QRM light, you will not be conscious of using low power.”




Joshua’s ATU-10 review update after new firmware upgrades

Many thanks to Joshua (KO4AWH) who shares the following update to his previous guest review of the ATU-10 automatic antenna tuner:

Update on the ATU-10: new firmware released

by Joshua (KO4AWH)

The short story is that David N7DDC has a Firmware update with a new tuning algorithm that seems to fix the previously seen failure to find a decent match. As noted earlier in comparison with the Elecraft T1, the ATU-10 still does not necessarily get as close a match to 1:1 SWR but it now does indeed find a good match making this tuner my go to for use with my IC-705.

Not previously mentioned, the ATU-10 is also designed to work with the IC-705 for tuning commands when connected with a TRS 3.5mm cable, not just as an auto tuner when given a signal. And, in practice it works just as it should. I actually took the IC-705 and the ATU-10 and worked a SOTA/POTA with the beta version of this new firmware. I ran a 35’ wire and it worked great allowing me to work 40m, 20m, 15m and 6m for a total of 26 contacts. As a followup to my previous testing with the prior firmware 1.4, below are my results with the current new 1.5 firmware.

Testing on August 20th, 2022

The only difference from the original testing is the 31.5’ radiator was replaced with a 35’ and I did not tune and record results with the T1.

Conclusion on the ATU-10

I now feel very comfortable recommending this ATU. newdiytech.com has a great price and the build quality seems just fine. With the new algorithm update, a good match is found. The ATU-10 works great stand alone and also works fully automatically when used with a IC-705. This configuration means you can put the ATU at the antenna feed point and run a control cable back to the IC-705 and have a 50 ohm across the coax to help minimize loss, making for a nice portable setup with great band hopping flexibility.

Of course, if interested, I sell a protection cover for the ATU-10 just as I do for the T1.

If your curiosity is strong, here is some testing I did for David as he was updating the Algorithm now used in firmware 1.5.

UPDATE August 3rd 2022:

David Fainitski N7DDC has released a test firmware with a new tuning Algorithm with some promising initial results. A quick test on each band in the table has been added to reflect the new algorithm. This is not a firmware update yet but I suspect it will be soon. Results are great as tested. I hope to see this in a new FW soon.

August 6th, 2022

A second test firmware from David Fainitski N7DDC with the ability to increase or decrease the L and C manually allowed me to verify if a better match could be made. Turns out in a few cases it could. After testing again with a Tufteln 9:1 T80-2X2 on a 41ft sloping radiator I was able to achieve much better results than with the current version 1.4. In two cases I was able to find a better match manually. I realized later that if I were to tune a second time the ATU-10 would find the same, better match, on its own. Again, not a full firmware update, i.e. you have to flash back to 1.4 if you want to be able to turn off the turner.

(Click to enlarge.)

August 7th, 2022

Another test firmware David asked me to check. This version seemed more likely to find the best match. I did have the ATU go to L0, C0 twice but then find a match on a second try. This happened once on 40m and once on 10m. Almost like it faulted but there was some switching/clicking involved before stopping, it just landed at a 3:1 or higher with 0 for L and C. A second tune however straightened it out. I did not record those two cases. Below are the results. I was able to find a slightly better match twice but I am sure one would never notice the difference during normal use. The improvement both times was within the error of SWR across the three device measurements.

(Click to enlarge.)

Joshua explores Unun insertion loss (efficiency) comparison testing

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!



Tufteln Antennas


Joshua tests the ATU-10 portable automatic antenna tuner

ATU-10 with TufteIn protection case

Many thanks to Joshua (KO4AWH) who shares the following guest post:

UPDATE: Please check out Joshua’s most recent review after updating the ATU-10 with new firmware. The results have improved dramatically.

ATU-10 Random Wire Testing

by Joshua (KO4AWH)

I had a bit of time to do some field tests and I recently acquired an ATU-10. So I jumped right in and did some ATU-10 Random Wire Testing. The testing was completed with a Tufteln 9:1 QRP Antenna configured with an elevated feed point sloper and a counterpoise hanging straight down. The coax feed was RG316 17′ with the ATU at the radio with a short jumper. Several different radiator lengths are used as mentioned below. The ATU-10 was sourced from newdiytech.com, price was $120.24 shipped to me in GA USA, Ordered June 25, delivered July 8th.

A quick list of ATU-10 Features:

  • 0.91″ OLED Display that shows Power, SWR and internal battery remaining.
  • USB-C Rechargeable LiPo 1.7Ah
  • Grounding Lug
  • Bypass Mode (When I set to this mode however it would tune anyways)
  • Latching Relays (No power needed to keep in position. Hold tune with ATU off)
  • Input port for communication with IC705 (and potentially others)
  • 7 Inductors, 7 capacitors
    • (Elecraft QRP)
      • C array, pF 10, 20, 39, 82, 160, 330, 660
      • L array, uH 0.05, 0.11, 0.22, 0.45, 0.95, 1.9, 3.8
    • ATU-10
      • C array, pF 22, 47, 100, 220, 470, 1000, 2220
      • L array, uH 0.1, 0.22, 0.45, 1.0, 2.2, 4.5, 10.0
  • USB-C firmware update (ATU shows up as a drive, simply copy the new firmware file to the device and it will automatically update)
  • Weight 232g (8.1oz)
    • Tufteln Case adds 23g (.8oz) for a Total of 255g (8.9oz)
    • Compared to the T1 with cover for a total weight of 187g (6.5oz)

SWR measured with a RigExpert RigStick 320, Lab599 Discovery TX-500 and the ATU-10

The test process was to first check the SWR on the antenna with no tuner. SWR values recorded from the TX500 and RigExpert Stick 320. Values recorded in the 2 columns under the “No Tuner” section. This was completed for each of the Bands listed in the table rows (see below). SWR values were the lowest in the band range for all recorded numbers. Continue reading Joshua tests the ATU-10 portable automatic antenna tuner

The Elecraft T1 Protection Case by Tufteln

Long-time QRPer.com reader and supporter, Joshua (KO4AWH), runs an Etsy store with a wide range of products primarily designed for field operators. Over the past few months, Joshua has sent me various prototypes for feedback and also to test in the field. You’ll see some of his antennas in upcoming field reports and activation videos. I’m very impressed with his designs.

If you’re an Elecraft T1 owner, you should be especially interested in his T1 Protection Case.

Joshua sent me an early version of this clip-on case several months ago and it immediately replaced the simple cover I printed from a Thingiverse file. (To be clear, the Thingiverse case served me well for a couple years, but I prefer this one since it doesn’t require a rubber band to hold it on the T1.)

The Elecraft T1 is a hearty little ATU and I don’t worry about damaging it while tucked away in my SOTA pack, but the little buttons on the front are prone to be pushed with any amount of applied pressure. This can result in unintentional operation which can accidentally place it in bypass mode or at least shorten the life of your 9V cell.

The Elecraft T1 is not an inexpensive station accessory and, at the moment, they’re about as rare as hen’s teeth. The lead time on new T1s is counted in months rather than weeks (at time of posting, this is due to vendor board issues).

The Tufteln Protection Case simply snaps on the Elecraft T1 and protects the BNC connectors, ground point, and the front panel buttons.

The case material is durable and adds very little to the bulk of the T1.

Of course, you can’t operate the T1 with the case around it because the BNC connectors are covered, but I have propped up my T1 on the case while using it on rough concrete picnic tables. I’d rather the case be scratched than my T1!

If you own an Elecraft T1 and don’t have a protective cover, I’d encourage you to either print one, or buy Joshua’s T1 case. For years, I simply removed or reversed the 9V battery to keep the T1 from engaging while packed, but that doesn’t protect the buttons and (frankly) it’s a pain to pop the battery out and flip it for each use (then to remember to flip it back when packing away).

The Tufteln case is a simple and affordable ($16.50) solution!

Thanks for sending this to me, Joshua. I dropped my T1 while setting up my TX-500 for Field Day and it protected my favorite little ATU!

Click here to check out the Elecraft T1 Protective Case on Etsy.