It seems your 49:1 Unun also has lost its three cable ties holding the toroid to the PCB ;-) My Banggood Unun arrived this week and they fell off immediately after opening the case. I will give it try hopefully next weekend ;-) 73 Arnd DJ9PZ AB2QP
Curious that the resistive contribution (Z) to the impedance (|Z|) increased on 40m. As to testing how "good" rhe unun is, how about running WSPR for some minutes with this and then repeating wirh a known good 49:1 unun?
This is by no means a scientific test, it’s just a way to see if the unun is slightly in the ballpark of working. And when antenna tuning weather comes along it will be properly tested with a wire.
Best is to use non-inductive resistors. Obviously not wire wound, but badly made film resistors can be inductive. GOOD film resistors are made to be non-inductive.
Thanks Morten. I can't recall seeing that test method before, but it seems to be working well. I need a budget weatherproof end fed just like that for my current needs. I'm looking forward to part 3.👍
Why would yu nod simply add smaller resistors to your chain to make up the difference? 2x 10R added would have brought you bang on? Or are we simply looking for "good enough?
Thankyou Morten, you have triggered a thought in my head. Operation Find 49:1 is in progress..
Happy to help!
It seems your 49:1 Unun also has lost its three cable ties holding the toroid to the PCB ;-) My Banggood Unun arrived this week and they fell off immediately after opening the case.
I will give it try hopefully next weekend ;-)
73 Arnd DJ9PZ AB2QP
You are correct. The zip ties came pre cut inside the box, but everything sits well without them, so I dropped adding new ones.
Curious that the resistive contribution (Z) to the impedance (|Z|) increased on 40m.
As to testing how "good" rhe unun is, how about running WSPR for some minutes with this and then repeating wirh a known good 49:1 unun?
This is by no means a scientific test, it’s just a way to see if the unun is slightly in the ballpark of working. And when antenna tuning weather comes along it will be properly tested with a wire.
Best is to use non-inductive resistors. Obviously not wire wound, but badly made film resistors can be inductive. GOOD film resistors are made to be non-inductive.
You are absolutely correct, but my point was to show how you could do a simple test with things you have around the shack.
Thanks Morten. I can't recall seeing that test method before, but it seems to be working well. I need a budget weatherproof end fed just like that for my current needs. I'm looking forward to part 3.👍
I was by no means the first hamtuber to show this, both Ham Radio Dude and The Smoking Ape has done it before me.
Thanks for that. Maybe I need to go and have a look. Maybe I wasn't concentrating enough.😊🤷🏻♂️
Why would yu nod simply add smaller resistors to your chain to make up the difference? 2x 10R added would have brought you bang on? Or are we simply looking for "good enough?
That was what I had on hand, and good enough is very often just that.
Nice test Morton on a cheap Balun! 73
Thanks Jeff!
Nice test!
Thanks Mike