-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
Lightning L6 matching
- Thread starter Jim5570091
- Start date
Should I remove both the feed lines to test for 50ohm match on the tuning stubs?
Do I remove only the side I’m hooking the analyzer to?
Do I remove only the side I’m hooking the analyzer to?
I get the question now...didn't know it had separate feeds.
The question is where is the polarization switch located? Relay??
I emailed the owner designer of the L6. And the manual says the same thing. Leave both feed lines connected. But I think that’s is for tuning for lowest SWR in the shack. We know from many post here and other formats that you either connect the analyzer directly to feed point or a 1/4 wave jumper. I’m thinking of if I clip my analyzer directly to the feed point I’ll be measuring results of antenna + Coax. It just don’t sound right. I would think I should disconnect both feed lines and connect my analyzer to the tuning stubs. But this antenna is a very unique bread of antenna.
The side not being tuned needs to be how it would be in normal operation. This means if the side not being driven (tuned) has 20 feet of coax running to the "switch" panel, and that coax is unterminated when not in use, then that's exactly how it needs to be when you tune the other side.
When George said to keep them both connected, I think he assumed you would be connecting your analyzer at the shack end of each of those cables.
If you are tuning by SWR alone, this should work ok, but if you are measuring the feed point impedance, then you want to OSL calibrate to the end of those aligator clips. The ideal length for a VNA test cable is 1/2λ, not 1/4λ. I would recommend the OSL calibration anyhow.
If you ever change to a real coax switch, you may need to redo this tuning process because most coax switches short the unselected port (which is opposite to what you have now with the unused coax being open) and could significantly affect the tuning.
When George said to keep them both connected, I think he assumed you would be connecting your analyzer at the shack end of each of those cables.
If you are tuning by SWR alone, this should work ok, but if you are measuring the feed point impedance, then you want to OSL calibrate to the end of those aligator clips. The ideal length for a VNA test cable is 1/2λ, not 1/4λ. I would recommend the OSL calibration anyhow.
If you ever change to a real coax switch, you may need to redo this tuning process because most coax switches short the unselected port (which is opposite to what you have now with the unused coax being open) and could significantly affect the tuning.