Many thanks to SWLing Post contributor, Dan Robinson, for the following guest post and review:
Photo by Chameleon
The Chameleon CHA-RXL Pro: Improved Amp Board Raises the Game
by Dan Robinson
Back in 2021 I reviewed the CHA-RXL loop by Chameleon. This loop antenna is sold by major retailers such as DX Engineering, Gigaparts and Chameleon itself – the company is a well-known name in antennas and other equipment for the amateur radio world.
I compared the CHA-RXL to Wellbrook 1530 and W6LVP loops feeding into a four-position Delta antenna switcher, and then to a Raven 16 port multicoupler which maintains good steady gain.
My Wellbrook is mounted on a telescopic mast about 15 feet above ground level, with a rotor. The W6LVP (using LMR400 coax) is tripod-mounted with an overall height from ground of about 12 feet. It has special filters to prevent strong medium wave signals from bleeding into HF.
I have since added a UK-made loop (essentially a copy of a Wellbrook loop but smaller diameter and made of metal) combined with a W6LVP amp. This W6 amp does not have filtering to block strong mediumwave signals. In all, I have four loops into my Delta switcher, which feeds about two dozen receivers.
There is by the way quite robust discussion at https://groups.io/g/loopantennas about various loops, including the Chameleon. And this past July, Steve Ratzlaff posted news about the upgraded loop amp board which will ship with what is now the CHA RXL Pro, saying:
“Chameleon has completely redone their CHA RXL loop amp board from the previous poor-performing loop amp that I tested some time back, and sent me one of the new production boards to test. I’m happy to say it tests very well especially for LF sensitivity, and I can now give it my “seal of approval”. The new board is a version of the LZ1AQ loop amp.”
Photo by Chameleon
It turns out, according to an email from Don Sherman of Chameleon, that Steve is one of the engineers who helped design the new amp board for the CHA RXL Pro, and on the Loop Antenna group he provides a folder in which he placed previous test results with “new files of the new board (sweep of the new RXL Pro loop amp, and a picture of the new amp PCB).”