Total posts : 45366
[quote:102690a2c1=”YvesRoy”]Does it exist a reflectomer for AM band to measuring the VSWR with my AM25?[/quote:102690a2c1]
This would be a real design challenge, and expensive for Part 15 AM power levels. Probably the most practical approach to optimise a Part 15 AM antenna system is to use a “ham” type communications receiver with a signal strength meter built into it. Connect it to a very short receiving antenna (or maybe none), tune the receiver to the Part 15 tx (no audio), and move it all far enough from the tx antenna so that the receiver signal strength meter reads in the lower 1/2 of its scale.
Now adjust the tap on the tx antenna loading coil, and any trimmer capacitor in the tx available for antenna matching for some combination of settings that shows the maximum signal on the receiver meter. Relocate the receiver further away, or shorten/remove its antenna as needed so that the signal peaks remain in the lower part of the scale as you tune the tx antenna system.
After each adjustment at the tx, check/re-adjust it for 100 milliwatts of input power per its instruction book. All measurements should be taken after the operator has moved at least 6 feet away from the tx antenna and any “ground lead.”
The Part 15 tx book may have some other approach in doing this, which should be used, if so.