Tag Archives: Joshua (N5FY)

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.

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.

Antennas, Articles, How To, News

Joshua explores Unun insertion loss (efficiency) comparison testing

July 24, 2022 Thomas Witherspoon 5 Comments

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!

Joshua

KO4AWH

Tufteln Antennas

Tufteln.net

Accessories, Antenna Tuners, Antennas, News, Reviews

Joshua tests the ATU-10 portable automatic antenna tuner

July 12, 2022 Thomas Witherspoon 19 Comments

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 →

Accessories, Antenna Tuners, New Products, News, Portable

The Elecraft T1 Protection Case by Tufteln

June 29, 2022 Thomas Witherspoon 13 Comments

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.