I got an inquiry recently from someone wanting to buy a slug for a square coil in an SX-28A.
When I looked at my RF modules from radios #1 through #3, all late model 28A types, I discovered a lot of the coils did not have slugs yet the forms had threads for them.
Having been recently looking at the round coils in the early radios, I recall that a lot of them have no provision for tuning slugs.
So this page is all about documenting which square coils do not have tuning slugs.
Here are some images of RF #2 modules as removed from radios #2 and #3. I didn't mess with them. As the (out ot focus) image
shows, various coils are missing slugs - but not the same coils!
Is it possible that during the tuning procedure, some slugs are removed all together because the associated capacitor can do the job?
No slugs in any of the four coils. This matches the round coils in the early radios.
Variable number of slugs in three of the six coils.
Has slugs in all six coils
Has slugs in all six coils
Page: /28A_coil_slugs/Slugs.shtml
Last modified: Friday, 24 Apr 2026