technology, amateur radio, scouting and me

Category Archives: Amateur Radio

Updating my portable station with a KX3

After receiving quite a good annual bonus, I looked at my wish list and decided to buy a new portable HF radio. Based on my massive satisfaction with the Elecraft K2, the decision was quite easy really. Yes, I’ve joined the KX3 brigade.

IMG_0166

I ordered it in kit form from Waters & Stanton on Good Friday and it appeared at my front door the following Tuesday. I reckon it took about 3 and a half hours to assemble. Why would anybody buy it assembled?

Included in the purchase were the KXFL3 roofing filter, KXAT3 internal ATU and KXBC3 battery charger. I also bought the MH3 microphone.

I debated about the ATU and charger as I will mostly be using this portable. I nearly always use tuned antennas when portable and I will be using a LiFePo4 battery pack for external power. That said, there are bound to be occasions when I would like to tune up a piece of string; and I’m nervous about taking the (homemade) LiFePo4 4S1P pack through airport security. So, I may end up using some┬áPanasonic Eneloop Pro 2450 mAh NIMH batteries for overseas activations.

First impressions are excellent. The receiver sensitivity is superb: even better than the K2, which is pretty good.

KSB2 problem found, and solved

I finally solved the problem with my KSB2 board. It turned out to be a poorly soldered joint on one of the transformers that terminate the filter. I found it by writing down everything I knew about the problem and using that to systematically exclude different elements in the system. The final clue was thatContinue Reading

More modules built

After a break, I’ve been back building more K2 modules. I’ve built the KIO2, KNB2, KDSP2 and KAT2 modules over Christmas. That’s the lot. All but the KATU module worked straight away, but I’ve got a problem with the latter. I’ve still got to resolve the lack of Mic gain on SSB and absence ofContinue Reading

It’s done, the K2 is complete

At least as far as the basic unit anyway. After getting over the VCO problem, I’ve been able to make steady, if slow, progress towards completion. The filters are only roughly peaked because I don’t have an RF signal generator. I will rectify that later as my next project is to build an RF signalContinue Reading

Making progress again

OK, we got past the problem with the VCO. After tracing through the signals, I checked the levels on DIN and CLK against the indicative levels in the manual. They were the wrong way up! At this point I got on to the Elecraft mailing list and started asking questions. Luckily, Don Wilhelm W3FPR wasContinue Reading

Debugging the VCO part 2

After spending a bit more time this evening, it appears that the MCU is working OK. I can see logic level changes all the way through the chain from the MCU, via the PLL to the Low Pass Filter. That’s as far I got this evening. More to follow.

Ahhh, we have a problem

Testing the K2 Resistance checks Pass Assemble the Case and plug in the Front Panel and Control Board. It’s starting to look like a radio now. Isn’t it small! 4MHz Reference Oscillator Calibration Check The target is 12090 kHz +/- 30 kHz. Mine is running at 12099.45. Pass. PLL Reference Oscillator Range Test. Target rangeContinue Reading