Re: 7.5” Loopstick LW antenna low inductance problem

Steve Ratzlaff

Assuming you're using a real R33 rod, which if you bought it from Amidon, is most likely the case, then it sounds like maybe your rod's permeability is lower than other R33 rods, and that other than rewinding and putting on more turns, you're stuck with this inductance. I realize the rods are very expensive ($20 here in the USA, plus shipping) so you probably wouldn't buy another one just to see if it gives more inductance. Depending on how low you want to tune in LF you may be able to get by with this lower inductance rod and coil. So you may want to just put it on the radio and see how low your particular radio's SiLab's IC tuning will go--maybe you'll get lucky and it will tune low enough.


Steve AA7U

On 8/22/2019 9:58 AM, igvitk@... wrote:
Hi all! I’m trying to make the 7.5” loopstick LW antenna according to the instructions. I used the Amidon R33-050-750 rod, 100/44 litz wire, made 122 turns of the coil, which is located exactly in the center of the rod and which length is 106,5 mm. However, the output inductance measured by the multimeter is only 1432 uh instead of 1700 uh. The similar result was shown by another multimeter VICY DM4070. I think that is a strong deviation. Can anybody help to resolve this problem?

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