Should contest rules allow and act upon 599K QRM reports?

Saturday, 28 February 2009

Small Wonder Labs SW40+ and embedded K1EL K-PCB (K12) keyer

Small Wonder Labs website:
http://www.smallwonderlabs.com/
and K1EL Systems
http://k1el.tripod.com/index.html
are two of my most visited websites for QRP gear and ham gadgets. In the past I bought 2 of the SW+ series QRP rigs (80 & 40m) and was and still am really pleased with their performance.

I really missed a keyer though and bought an external K12 keyer from K1EL to use with both rigs. This worked fine, but the whole point of these small rigs is their simplicity and portability. So to keep things simple, I decided to buy the same keyer chip (K12) but in K-PCB format which was small enough to mount inside the transceiver case.

The K-PCB kit takes around half an hour to build and the same again to mount inside the SW+ rig (it's so light I just used cable ties). The kit is $10 which is unbelieveable value for what you get and it fits easily inside the SW+. Unfortunately my kit was missing a 1000pF cap which I replaced from the junk box and the 2N2222 NPN transistor (used to switch gnd to the keying line of the SW+) had to be replaced.

The only slight question was how to get the sidetone into the audio chain of the rig? The K-PCB has a low level AF output for this purpose and after some experimenting I found that the best place to connect it to was the top of resistor R10 (vertically mounted) on the SW+ pcb. That done, I could hear CW commands from the keyer chip through the RX audio of the SW+.

Have a look at the above websites for details on the two kits they really are worth every penny.

2 comments:

aaa said...

I've also bought the SW40 to get into CW. I'm just puzzled what a keyer is used for? I see different uses attributed to keyers, you mention it's for getting the sidetone to match frequency?

GM0ELP said...

A straight key provides 1 contact to earth. An iambic paddle key provides 2 contacts to earth (1 for dahs and 1 for dits). The SW40+ kit is designed for use with a straight key. The insertion of a keyer board allows an iambic paddle to be connected to the sw40+. It's less tiring to send using an iambic paddle due to the semi-automatic nature of sending strings of dit and dahs amongst other shortcuts.