Thor's Hammer up and running

During some work at the place the PC had been switched off.

The "Hammer" is running nicely again since Christmas.

It is running on 10MHz and 500kHz as before. Possibly with an extension in a few months. Some antenna work and some soldering needed.

Next band will probably be 80 (3500kHz). and a simpler receiver for 10MHz. The original receiver will then be set to yet another band. Some wideband antenna work will be necessary for this to work out.

Time to get the soldering iron warmed up again.

On the PA9QV front the next soldering project should be the FA-SDR. All components including the housing have arrived, only a PA (1W) is missing yet. I may build a small wideband PA myself.

Still a lot of kits to build, but slowly getting started again.

Enter the DDS

Just received a kit, the DDS-2 from N3ZI.

The kit contains all parts, including a simple display, for making a functional DDS.

The kit is relatively easy to assemble, all parts were present. The SMD integrated DDS chip is somewhat more tricky to solder without creating solder bridges. I think the pads are a bit wider than the pads for the NE612 SMD mixer on the Rockmite/Warbler kits from Small Wonder Labs.

First the bad news : Tuning the DDS-2, as it is, is an exercise in patience. it is slow, when trying to use the fast function (turning the knob faster), the tuning becomes erratic. The lack of a keyboard entry function is serious with such a slow tuning.

It looks like a modification of the firmware should be attempted. Quite a daunting task, given that (as far as I know) the source code is not available, and my programming skills are not that good.

The good news is that the temperature stability looks fine. the crude "switching on and off the fan" method revealed about 20 - 25Hz drift on 10 MHz, of course relatively less on lower frequencies. For a non- temperature compensated clock oscillator this feels quite good, and I would expect better stability when the DDS is boxed.

Other good new on the DDS-2 : even if tuning is a bit of a pain, there are two redeeming qualities :

- the standard firmware has 10 "memories", acting like the "Band stacking" feature of many modern transceivers. so a multi frequency MEPT with 10 (11) pre-programmed frequencies is quite doable

- the application of the RIT should be quite useful for generating FSK easily, eg for a relatively frequency agile MEPT.

However, for more experiments I did order a DDS60 daughterboard that should be programmable from a PC or an external (PIC, PICAXE etc) microprocessor board.

Building SDR for 80m

Today I received the kit from the magazine "Funkamateur" with all necessary parts to build a "single frequency SDR", similar to the SoftRock, along with a few other components for my constructions.

Like for Joachim, one resistor had a 1000 times larger value than the one needed. No problem, since I had one of the correct value.

Some solder smoke generated, not quite finished yet, but it is time for some reading.