eLCie rides to the rescue

I noticed that JLCPCB:

https://jlcpcb.com/

now does 3D printing.  So I decided to try it using the design file provided by Farhan (of Bitx fame) for a PTO coil form.  It cost $2.97 for 2 of the forms plus $4.10 for the cheapest postage.  Note that that $7.07 total includes a 50 cent fee for using Paypal.  It was ordered on March 1 and I received the two forms on March 17, 2023.

Then I tried winding a coil for a 7 MHz PTO design by N2CQR:

https://soldersmoke.blogspot.com/2023/03/fixing-tuning-problem-in-high-school.html

I got out the LCD LC meter that I had purchased on ebay.  This is a shifted oscillator type of LC meter.  Per Bill's page the coil should have an inductance of about 1.4 uH with 21 turns, so I wound 21 turns of fairly stiff magnet wire (20 gauge ?).  Using the LCD meter I got .58 uH with the brass screw "all out".  With it all the way in I got .47 uH.  So clearly something is weird.

I then dug around and found my Morse code based LC meter, eLCie from the NJQRP club, designed by KD1JV.  Using it I got 1.73 uH "all out" and 1.29 uH "all in" - these sound a lot better.

So now I'll have to try and figure out what is up with the LCD LC meter.

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm