Monthly Archives: March 2010

New tool + Receiver Mixer Stage completed

Here’s an updated shot of the circuit board showing the receiver mixer stage work (middle left).
Circuit board is held by my new PanaVise 333 (thanks, Hon!).  What a huge improvement over the wimpy Radio Shack third hand tool! Soldering and inspection work is pleasure now instead of being tedious and frustrating.
Now I can leave the circuit board in the PanaVise for soldering and inspection since the PanaVise allows 360 degree rotation, simplifying inspection and trimming. It also saves a lot of time and effort.
Using the PanaVise avoids damaging circuit board edges since the circuit board is gently held in place along grooves in the holding arms. 
In contrast, the teeth on the Radio Shack third hand tool alligator clips damaged the circuit board surface. 
Plus, once components are installed along the edge of the circuit board, there is little to no room for attaching the third hand clips. Not a good situation.
Lastly, the base of the Radio Shack tool is simply too light and shallow to provide sufficient counter-balance and weight while performing soldering and inspection operations. The PanaVise is one of the best tools I own for electronic kit building! Well worth its $65 price tag on Amazon.
Next up: Installation of the 4-pole crystal filter along with the 11 MHz IF Amp.
After that, it’s on to the BFO and audio amp sections of the kit.

Transmit mixer and 7 MHz filter circuit

Transmit mixer and 7 MHz filter circuit components successfully
installed and tested. Located on left side of circuit board. Only
had one problem in this section. After a bit of trouble-shooting
I discovered I had installed a wrong capacitor. Removed it,
installed the right one and all worked well.

Next up: The receiver section. No testing after this section,
so installation must be perfect.

VFO construction

I’ve finally resumed construction on my TenTec 1340 QRP kit.  The photos here show completed work on the VFO section.
Once again I am indebted to K7QO for his very valuable step by step photo guide to building this rig. I referred to his guide numerous times to verify correct component placement and selection when the supplied documentation fell a bit short.
Photo below shows the setup for VFO testing. After creating and then fixing an inadvertent solder bridge in the late stages of this section I was a little worried I might have more repair work on my hands. But after I hooked the PC board and the ICOM to my power supply, powered up, tuned the ICOM to 4 Mhz, and tuned the VFO a bit I heard the sweet sound of success! A clear tone from 1340 right where it should it have been.
Next, I need to adjust the toroid coil to set the frequency range.