Hi Dave,
I'll see what I can do to borrow another receiver. Otherwise, your Softrock suggestion seems perfect. As for the chipped resistor; I seem to have taken a very small bit off the surface at one corner. It's the black material with the value etched on top of it. I guess the edge of my screwdriver chipped it off when I was attempting to hold it down. I'm surprised it chipped so easily as I did my best not to apply too much pressure. After soldering, I did test resistance however, and got a reading of 13.4 k ohms. That seems to be within a 5% amount of variance. I don't know what the tolerance range is for this part though. Should I replace this resistor with another, or use the leaded one included with the kit? Mni tnx es 73 James K2QI _____ From: G3TJP [mailto:g3...@lanks.plus.com] Sent: Wednesday, January 06, 2010 8:33 PM To: k2qi....@gmail.com Subject: K3 IF output I've been following your adventures re the mod to the IF output of the K3. First of all, the signal present at the IF output is at the microvolt level - pretty much a signal level that you'd expect to come from an antenna. Rather than borrow a spectrum analyser, which may be quite difficult to organise, why not borrow a receiver? A spare rx. is of immense value. If you can borrow a rx., connect its antenna input to the IF output, tune the rx to 8.215MHz and then apply your 50uV signal to the K3 and tune it in, first on the K3 and then on the borrowed Rx. You should hear it tune in on both receivers - the K3 and the loan radio, although the IF on the K3 isn't necessarily spot on 8.215MHz. You can tune the borrowed Rx across the K3's IF bandwidth, so there you have it, the borrowed receiver is an aural spectrum analyser. If you can't borrow a Rx., you could build one of the softrock software defined radio modules that's designed for the K3 IF and use that with a computer and free SDR software to listen to the K3's IF. If you were troubled by the Softrock's oscillator feedthrough, one of Jack Smith's Clifton Laboratories Z10000 buffer amps would help. Hey, if you build them both, you have the structure for a panadapter using Rocky software and a high quality soundcard in your computer. I've built one and it works just fine, but I haven't yet figured out how to do point and click on the frequency display to control the K3's tuning HI! The two kits I've mentioned are cheap! One's around $15 and the other's around $25, IIRC. They will be a good intro into the world of SDR. It's generally not a good thing to chip a bit off an SMT component. Resistors are normally tiny bricks of ceramic that have a resistive coating applied on one side (usually the top). This is then whittled to the required resistance by laser action. The conductive ends are then sputtered onto the chip. The surface of the laser-cut resistive element is then epoxy coated for protection. The secret of SMT wrangling is to pin the little xxxx down using vertical pressure. My SMT pinning rig consists of a bent wire coathanger to form a base with an arch (with kinks in it) until the last bit, which points downwards. To that end, I fix a cocktail stick (they're nice because the tip doesn't usually skid on the SMT's surface, but you do get through quite a few cocktail sticks HI! The kinks are there to hold a couple of fishing weights in place to provide downward pressure. To join the stick to the mutilated coathanger, I use the insert from a choc-block connector. One screw holds onto the coathanger and the other holds onto the cocktail stick. It all boils down to having a means of applying pure vertical pressure on the component you intend attaching. For simple SMT rework involving removal of a component, Google Chipquik. Brilliant stuff if you follow the instructions. They do free samples, so if you're frugal with it, a free sample will last a long time! There you go, I hope there's something in the above that is of help to you. 73 DaveL G3TJP ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
