26-05-2024, 12:28 PM
Well, I have finally got back to this.
A couple of weeks of illness, then a couple of weeks in YJ land got in the way. (After over 30 years of visits to YJ I appear to have come home with one of the tropical bugs - waiting on tests for malaria, dengue and ross river. However the sun is out and I have a brand new NanoVNA in my hot little hand, so dengue or not the ladders came out.
Now, you see, this is why I don't like making antennas (kidding). As I am waiting for some SMA to PL259/SO239 adapters for the VNA, I decided to forge ahead with a combination of adapters and leads. After an hour or so of up and down ladders, trim this,change that I still had weird numbers from the VNA, 4 ohm impedance, then 150 ohm, etc.
Time to start again. I'll recalibrate the VNA and go step by step. As I started to disconnect VSWR suddenly dropped to 1.13:1. Hmmm. I started moving and flexing cables and adapters and up it went again. It was one of the test cables, which is now two halves of a test cable...
Why does this always happen? I chase my tail for ages only to find it's not the DUT but the test set up. Just lucky I guess
After lunch I might just have a listen around 50MHz to see what I can hear!
A couple of weeks of illness, then a couple of weeks in YJ land got in the way. (After over 30 years of visits to YJ I appear to have come home with one of the tropical bugs - waiting on tests for malaria, dengue and ross river. However the sun is out and I have a brand new NanoVNA in my hot little hand, so dengue or not the ladders came out.
Now, you see, this is why I don't like making antennas (kidding). As I am waiting for some SMA to PL259/SO239 adapters for the VNA, I decided to forge ahead with a combination of adapters and leads. After an hour or so of up and down ladders, trim this,change that I still had weird numbers from the VNA, 4 ohm impedance, then 150 ohm, etc.
Time to start again. I'll recalibrate the VNA and go step by step. As I started to disconnect VSWR suddenly dropped to 1.13:1. Hmmm. I started moving and flexing cables and adapters and up it went again. It was one of the test cables, which is now two halves of a test cable...
Why does this always happen? I chase my tail for ages only to find it's not the DUT but the test set up. Just lucky I guess
After lunch I might just have a listen around 50MHz to see what I can hear!
Colin
Barossa Valley, SAP. PF95ln
(aka VK5CSW)
Barossa Valley, SAP. PF95ln
(aka VK5CSW)