On Tue, Jan 28, 2025 at 12:33 PM, Martin - Southwest UK wrote:
However, as I've said before, there isn't much additional effort required to build an LZ1AQ type circuit, but the improvement in performance is substantial.?
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Apart from the novelty of building something, the PA0FRI, and the G8CQX it is based upon isn't that good, and personally I wouldn't bother.
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I can think of 3 situations where the PA0FRI may be preferable to the LZ1AQ.
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1. Long (read: lossy) coax between active loop & receiver, e.g. 1st floor of a 30-storey flat.? PA0FRI has significantly higher gain over 6-18 MHz, which can overcome the coax loss.?
/g/loopantennas/photo/297909/3880257The OP Dhiru's version which uses a 4:1 output transformer has even higher gain that the above graph which is based on the older 1:1 version.
2. Where better CMRR is required, the PA0FRI's differential amp has an edge over LZ1AQ's common base.
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3. Eliminating the plastic enclosure. PA0FRI's smaller PCB can be shoved inside the PVC pipe.
73, Leong, 9M2LCL, ex-9W2LC.
