Next Events


lcd club night

15th July 2024

Annual DF Hunt

In the

Welland Valley

Meet outside

The Great Bowden

Village Hall at 19:00

Paul  G1FJH

is the Fox and organiser for this years DF Fox Hunt


club_sked

 1st July 2024

19:30 to 20:00

Meet on 145.275MHz FM

Net Controller

James G1JSP

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23rd June 2024.


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50 ohm Dummy Load




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Build Instructions by Tim G8JFX

Tools Needed

M3 and M4 taps
Suitable tap handle
2mm and 2.5mm Allen keys
Square ended pliers
Soldering Iron + solder
Needle files (round and flat)
Tin snips or strong scissors
Small bit of metal type abrasive paper

Build Method  


(1) Tap 6 off M3 holes in heatsink (use some sort of tapping lubricant)

(2) Tap 2 off M4 holes in heatsink (use some sort of tapping lubricant)

(3) Clear swarf etc from holes

(4) Test fit the PCB. Fix any mis alignment of holes. File the PCB if required.

(5) Solder the SMA socket to the PCB. Ensure alignment is good (it’s tight). Don’t overdo the amount of solder on the bottom particularly.

(6) Test fit the PCB again. Ensure it’s fitting flat to the heatsink. Fettle the heatsink and SMA legs under the PCB as required.

(7) Fit the PCB with 6 M3 screws.

(8) Drop the resistor into the slot, ensure the tab lines up well with the PCB track. Put a small amount of thermal grease under the resistor. Fit the 2 off M4 screws. Not too tight !

(9) Solder the tab to the track. Not too much solder.

(10) Get the load tested.

(11) Now make the 30mm X 38mm shield box. Walls are 6mm high. Cut out corner squares. Fold the walls using pliers, just a little at a time.

(12) Cut out the relief for the SMA (see picture). Just cut the edges And then “wobble” the center piece ou

(13) Lightly abrade the outside wall of the box for soldering.

(14) Solder the box to the PCB. Corners and centre of walls is enough.

(15) Solder the top of the SMA to box.

(16)       FINISHED…….  Now to check work and test........

 

                



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