NEW LIFE FOR OLD FRONT PLATE

We all need metal cabinets for our projects. Their prices are often exorbitant.
You can find cheap used cabinets. Unfortunately the holes left by the switches and potentiometers on the front makes them difficult to reuse.

Opportunities :

- Cut an aluminum plate or FR4 epoxy to rebuild a front face, very time consuming
or
- Fill the holes, there is nothing to cut !

I managed to fill holes with a product bought in a store for automobile.

It’s a filling compound for car repair made by PRESTO, ref 443596.

Cost is 10 € for 250 g. Lots of front plates for this price.

The compound

Results

Because the plate and the compound are not the same colours, you can see the holes.

By touching, it is impossible to detect the holes.

EFHWA TRANSFORMER

Some tests with transformer for end fed half wave antenna, EFHWA.
2 turns primary + 150 pF, 16 turns secondary seems to be good for 40-10m
3 turns primary + 150 pF, 24 turns secondary is good for 80-20m

FT240-43

Primary : 2 t, 

Secondary : 16 t

LIGHT TWIST

C=150 pF              Rtest = 3,1 kΩ

     

3510 kHz	7029 kHz	10140 kHz	14016 kHz	18096 kHz	21054 kHz	24930 kHz	28041 kHz
SWR = 2,61	SWR = 1,33	SWR = 1,11	SWR = 1,28	SWR = 1,41	SWR = 1,39	SWR = 1,30	SWR = 1,44

FT240-43

Primary : 3 t, 

Secondary : 34 t

TIGHT TWIST

C=150 pF              Rtest = 3,1 kΩ

3510 kHz	7029 kHz	10140 kHz	14016 kHz	18096 kHz	21054 kHz	24930 kHz	28041 kHz
SWR =  1,57	SWR = 1,29	SWR = 1,33	SWR = 1,65	SWR = 2,46	SWR = 3,85	SWR = 7,14	SWR = 13,63

 

Construction of 40-10m transformer
The plastic box is G311 (IP65)
Ref Farnell 1094700 price< 8 €

Ready for real test with End Fed