Thread: Mini-Mod 2021!
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Old 25th Mar 2021, 9:12 pm   #29
Ian - G4JQT
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Join Date: Jun 2004
Location: Reading/Fakenham, UK.
Posts: 1,320
Default Re: Mini-Mod 2021!

Quote:
Originally Posted by OldTechFan96 View Post
^I've not long finished building my MM and the FET supplied by Spectrum DID need to have its connections swapped to fit on the PCB.

What adjustments need to be done to the coils? Is there any instructions for this?
Here attached below is the original BVWS Bulletin article. It is also posted in various other MiniMod threads, but I'll post it again here. It explains how to set the inductors and antenna length. The circuit has evolved a little.

1) Q1 now BF256 and the new boards have the GSD in the correct place - at least for the BF256s I have.
2) Q2 is any general-purpose equivalent to a BC109. The BC548 is a suitable substitute, but check the orientation of the EBC leads.
3) R2 now 3k3 (3.3k ohms)
4) C12 680n is not as easy to source as 470n, which will be OK as an alternative.
5) The LED is an addition. I didn't use one in my original design as it increased the total current consumption by about 50%. But new high brightness/low current LEDs make it a useful mod.

Also attached are the instructions I sent out with the MiniMods when I was making them myself.
Attached Files
File Type: pdf The_Bulletin_2011_MiniMod2.pdf (777.5 KB, 220 views)
File Type: pdf MiniMod instructions.pdf (127.9 KB, 185 views)

Last edited by Ian - G4JQT; 25th Mar 2021 at 9:19 pm.
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