I have a couple of other Common Mode Current Chokes laying around the shack. One of them is the COMTEK COM-CFC-50A. It’s a beefy choke, rated at 5KW – about 6 feet long and covered with 75 ferrite beads over some Teflon RG-400 coax. It isn’t a field device, for sure, and weighs in at about 3 pounds.
I’ve been having some issues with noise on 40m, and wanted to see if a Common Mode Current Choke would help reduce it. Since I sometimes run my KPA-1500, I needed a choke rated for power. That said, I was curious how it performed, so I ran the identical tests on it, that I did with the PackTenna PT-202/PAK-103, and this is what I saw:
- 33dB on 80m
- 36dB on 40m
- 38dB on 20m
- 33dB on 15m
- 30dB on 10m
I actually had a bet with myself that this would outperform the PackTenna – I suppose it depends on your perspective, the COMTEK choke has a slightly flatter curve, especially evident at higher frequencies, which is likely better for my home station, but for the most part it has slightly less reduction in common mode current.
