| Application | Amateur Radio |
| Kit Name | QRP Manual Days Antenna Tune Tuner DIY Kit 1-30Mhz |
| Kit Version | Kit does not have version numbers (even though it has changed). PCB is marked with V2.0 |
| Parts needed | Kit from Banggood, Ebay, Aliexpress, Amazon |
| Date Last Revised | 24th May 2021 |
| Changes Made | Heavily Translated and contributed to the original translations (Was 7 Pages Now 34 Pages) |
| Learning Outcomes | To build a build an Antenna Tuner for low powered transmitters (<10 watt) |
| Document Format | Downloadable PDF (Button and the end of this page) |
This Antenna Tuner is otherwise known as :
QRP Manual Days Antenna Tune Tuner DIY Kit 1-30Mhz
or
QRP Manual DIY Antenna Tuner Kit 1 -30Mhz
This little QRP (low power) Antenna tuner has been around for a while and it is sold as a Kit from Aliexpress, Amazon, Ebay, Banggood to name a few. The price ranges from $8.00 through to $60 (discounted 🙂 for the same group of components.
The design is actually quite simple, building on some existing designs and reference documents such as . It is in effect a T-Topology Antenna tuner.
What lets this kit down however is some of the errors in the kit parts, and the almost non-existent instructions. I say almost non-existent, as in most cases, there are no instructions from most suppliers, you have to do a lot of googling to find the instructions, and when you do, you get about 7 pages, mainly written in Google Translated Chinese to English. In fact I think I got more fun out of trying to work out the original words or sentence meanings than building the kit.
Now I have had my say and I will state that I took it as a challenge to complete the project and get it working. I am glad I did as I learnt some things on the way. It does work and due to space restrictions, I am using a 21m resonant Dipole with an 80m 3watt Transceiver and achieving 1:1.3 SWR with this tuner.
Now if you have arrived on this Website looking for some decent instructions, then you have come to the right place. When I set out, I decided to photograph everything, as well as re-write the instructions. So you will find that we have now gone from 7 pages of instructions to 32+ pages (with some helpful hints).
If you find I have made any errors or mistakes, please let me know in the comments below.
NOTE: A revised document is currently underway. As Rob points out in the comments there is yet another fatal flaw in the project where the taps need to be reversed. I had already realised this and corrected my unit last year, but have been slow on updating the instructions. If you understand what this means, you can still build this project and correct, but if not, I hope to have the instructions corrected in the next month or so which should be version 2.2
found this unopened kit in a box in the shack. you total hero, sir. carl
Carl,
Glad it was of use to you.
Just keep an eye on an update to the article shortly. On my last use a few weeks ago (I noticed the coverage action appears to be “off” slightly).
I am going to revisit (with a clear head) and check that nothing has been reversed.
Regards
Bob (VK1ERF)
Hi Bob,
I just watched a Youtube video by Carol KP4MD who also struggled a bit with this antenna tuner kit. She says the taps on the schematic are actual backwards in the instructions. Reversing the taps makes the tuner work properly across the HF bands. I would be interested in hearing your comments to this video. 73 ZS1SA
Rob,
Carol is spot on. When I was building the unit, I was mainly working on 40m with CW.
At the end of last year, I pulled it out as I was working on another project, and recognised that the it did not cover the entire HF band (not even close).
I actually spotted the issue then and I have corrected mine, and I started a complete revision of the instructions (including some poor grammar), but other things have got in the way and I have not had a second to get back to it.
The whole project is riddled with errors. The concept is sound and covered by many other projects well, but this project and its instructions are not worth the $30+ I have seen it going on some chinese sites.
However, like always, a failed or poor project is not a failure if you learn a lot from it, and I will have to say I learnt a lot about tuners and what they actually do (or don’t)
I appreciate you raising it however, as I will (at least until I complete the revision) will add a note to the main download page
Regards
Bob