Clark Martin
KK6ISP
On Mar 15, 2017, at 1:33 PM, richard kappler <richkappler@...> wrote:
All,
I'm a computer geek, not an EE, so some of this is not obvious to me.
1. The volume pot has 5 leads, 3 around the circumference and 2 out the back. Am I correct that the two out the back are for the on/off function?
Correct.
2. I've seen mentioned here and on a coupla youtube vids that one needs to wind ones wires. Is that all wires? And why do we do that?
Do you mean twisting the wires. It reduces signal coupling, IE RF getting into the audio via the pot leads for example.
3. I seem to recall reading in one of the recent posts that the instructions at HFsigs are incorrect for one of the wires, but darned if I can find the post. Can somebody shoot me a clue?
4. This is my first ever build, so I'm doing it in a plastic case, essentially storage bin with the slightly larger footprint as the shipping container but about 4 times as tall, to make it easier on me (no workshop at the moment) and to save a few shekels. There has been a lot of talk lately about heat issues, so I've ordered a heat sink for the VR on the raduino board, and concurrently ordered a pair of small (25mm iirc) fans for the case. I intend to use one to blow directly on the AMP heatsink, perhaps the other to exhaust air from the case. Any issue with just tapping off the 12V main for these? Obviously it would work voltage wise, but would it interfere with the radio?
On caution about the storage bins. The type of plastic they are commonly made with grows brittle with age and UV exposure. In normal use it takes some time for this to be a problem. But drilling holes in it will cause trouble sooner.
I think one fan should do, if that is even necessary. Drawing off the radio¡¯s 12V supply shouldn¡¯t be a problem. You might want to check once it¡¯s all working to see if the fan causes in noise in transmit or receive. Try monitoring an ongoing QSO and disconnect / connect the fan to see if you can hear anything.
You may want to run the fan off the transmit power contact on the relay. Ideally the fan would run a few seconds longer but it should work pretty well this way.
