Jan G0BBL offers interesting components and kits via the website www.sdr-kits.net. One of them is frequency synthesizer kit based on si570 circuit controlled by Atmel. This circumvents the usual way of controlling the si570 circuit via USB. The PA0KLT connection uses a rotary encoder for tuning, four control buttons and a two-line backlit LCD display. The control firmware allows the smallest tuning step of 1Hz, switching between VFOs, VFO B a 32 memories. It is also possible to configure the frequency offset and frequency multiplier (suitable e.g.. pre SDR, where 4 times the required frequency is required). The advantage is the BCD output with information about the set band, which can be used, for example, to switch bandwidths.
I received the kit by mail about a week after ordering. The construction is a mix of classic and SMD components. SMD blocking capacitors are supplied in o 1- to 2 extra pieces, which has worked very well. The capacity value is also marked on the packing tape with a colored marker. The printed circuit board is double-sided, tinned and covered with a solderable mask outside the contact pads. The construction and revitalization procedure is in the manual, which is available on the website. I recommend following it.
Completed kit PA0KLT with si570
The biggest difficulties are with soldering the si570 circuit. The terminals are on the side in the slots and as flats on the bottom of the integrated circuit. The soldering on the bottom worked for me in this way, that the IC and PCB surfaces are tinned first, The IC is placed on the printed circuit board and the tin on the printed circuit board is melted by the micro-solder and poured with the tin on the IC. Depending on the si570 version, do not forget to make an output connection on the printed circuit board.
The supplied switches are not of the highest quality, enough to revive and try. In my case, there was no problem with recovery, all voltage and current readings agreed. Stabilizer 7805 I recommend adding a cooler, especially if the supply voltage is higher than 10V.
Although the connection is not complicated, but requires experience with soldering SMD components and basic measurement techniques (A, V, I recommend a counter or oscilloscope). The advanced designer is able to make the basic part of the HF equipment at a relatively favorable price (RX, TRX, HF generator etc.).