It would be nice if you could clean the insides of the switch, the goal being to improve the electrical connection of the grounded-out connectors, and repeat your tests. I have a Daiwa brand switch where the isolation appeared to double after the cleaning. The inside of the switch had a thin coating of oil inside. In addition to removing the oil, I also lightly burnished the ground contact surfaces to remove the slight metal oxide from the switch casting. I then added a small dab of Deoxit to those same surfaces. I realize you have your own priorities, but if you should conduct this experiment please publish your results. Thanks and 73.
If you had calibrated the VNA at the ends of the cable (and even better after the UHF adapter) and not the output of the switch you could have also measured the input VSWR of the switch as well as the loss through the switch.
Interesting how bad the isolation is. With "real" switches like the ones I sell, 60dB isolation is often the specified minimum, even in the GHz+ range.
Those really are the worst switches. I’ve had mine completely fall apart. When I opened it up to rebuild it, I was dismayed to see what little thought went into the internal wiring.
they're aimed at the CB market and the idiot ham market. idiot ham as in those that pass the easiest, simplest test and don't have a clue but over night they become radio encyclopedias..
It would be nice if you could clean the insides of the switch, the goal being to improve the electrical connection of the grounded-out connectors, and repeat your tests.
I have a Daiwa brand switch where the isolation appeared to double after the cleaning.
The inside of the switch had a thin coating of oil inside. In addition to removing the oil, I also lightly burnished the ground contact surfaces to remove the slight metal oxide from the switch casting. I then added a small dab of Deoxit to those same surfaces.
I realize you have your own priorities, but if you should conduct this experiment please publish your results.
Thanks and 73.
If you had calibrated the VNA at the ends of the cable (and even better after the UHF adapter) and not the output of the switch you could have also measured the input VSWR of the switch as well as the loss through the switch.
yes, I bet it is terrible. I didn't want to confuse things. just concentrating on isolation
Make sure the nano vna is in channel 1 (display-channel,)
I think you need a load on CH1 during isolation cal
Would it be possible to switch the floating unselected outputs to ground?
Interesting how bad the isolation is. With "real" switches like the ones I sell, 60dB isolation is often the specified minimum, even in the GHz+ range.
Thanks!
Thanks for sharing. Great video. You didn't really address what an acceptable level of coupling is. It would have been interesting.
a viewer below says the good switches are >60db isolation
@@tcarney57 It's not just a matter of damage, but also how it affects receive sensitivity.
Those really are the worst switches. I’ve had mine completely fall apart. When I opened it up to rebuild it, I was dismayed to see what little thought went into the internal wiring.
they're aimed at the CB market and the idiot ham market. idiot ham as in those that pass the easiest, simplest test and don't have a clue but over night they become radio encyclopedias..