Do you remember the Denco plug in coils? ?long ago, I had a regenerative receiver kit that handled band changes just like that. They were really terrible things, they could jump several kilohertz if you moved your hand to the tuning knob or off it after you'd tuned something in.
Done a mod today to make use of Hans pluggable LP filters...
Mounted the filter sockets on some PCB on the lid of the case.
These are coax wired internally and I can just swap out filters without opening the box.
A small metal box then clips over the filter to screen and protect them..
Picture here...
Running a test on 10 meters WSPR today into a loft dipole..
Conditions are poor but I'm getting spotted and the U2 is nice and stable
Philip G4JVF
--- In QRPLabs@..., "Philip" wrote:
>
> Received my second kit this morning....thanks Hans
>
> I had a box ready prepared for it.
> This large box is designed so I can tinker with things like
> filters power supplies and PA stages hence the roomy interior.
>
> MK1 test bed is using a separate PA stage (no FETs on the kit board).
> Driven from the DDR, this PA transistor gives me the output powers
> shown scribbled in the circuit diagram.
>
> I'm going to add a drive pot so I can set the output on all bands to
> say 200mW or whatever.
> This PA can drive a simple IRF510 to 3 or 4 watts if needed.
> The kit board switches a relay which switches the 12 volt supply to the
> PA when in transmit..
>
> Using external switchable LP filter box...
>
> Rear panel has a 5 pin DIN socket for the external GPS module....
>
> Much fun tinkering to come :)
>
> Photos in this link...
>
>
>
>
> Philip G4JVF
>
