VE9QRP

Because I'd like to move to the SGP4 tracking algorithm for QRPtracker (and failed to port it well to the 8-bit ATMega644) and because there's no substitute for real programming power, I'm playing around with the PIC32 processor, as conveniently provided in the CUI32 experimenter's board. My goal is to milk this for all its SRAM and flash, but keep the power down to the single-digit mA level so that I can use a pair of AA batteries to power it. Here's some power observations to get things going:

My current iteration of the Satpack full doppler tuning device has about 30k of code space still available in the target hardware, a atmega 644p. Some of this will be eaten up with error checking around the tle loading and clock-setting, but there's still a fair bit of open space there. PC-based tuning programs will often tell you if a bird is eclipsed or in the sun, a feature that is even more useful these days as the aging AO-51 is not transponding in eclipse. Similarly, the AMSAT-UK video entitled 'FUNcube part one' states at its end that FUNcube will have a high-power telemetry mode while in sun (roughly when school is in session), and a low-power telemetry + transponder mode when it is in eclipse (roughly when school is out). This scheme fits the FUNcube KISS principle, but won't be ideal for the small but important number of students who live in Arctic regions. So a 'sat in sun' indicator on the LCD is going to be more important than ever, but I wonde...

Recently, I asked the amsat-bb list if its members knew of any obscure CAT controlled radios which I might doppler tune with my satpack project. Sergej, UZ2HZ, kindly pointed out to me the FT-727R . According to the previous link, "All serial data consists of single byte binary codes sent at 4800 baud, TTL levels, with two INVERTED stop bits and one INVERTED start bit." Yikes. Still, the price might be right for this HT. Another possibility is the Yaesu FT-5100 . It can be controlled at ttl levels with a modified mike interface.

The utility of a portable full doppler tuning device will depend on how easily it can be updated with new Keplerian elements, so I've put some considerable work into the program that does this through a USB/serial connection. Here's a GUI version demonstrated:

The performance of my 435 MHz AA2RX lindenblad has not been quite as good as the simple vertical that it replaced, leading me to take the assembly down and debug it. I don't have an antenna analyzer, so I relied on a good ole' 70cm SWR and power meter with a two-carbon-resistor 5w dummy load.

The pcbs shown in the previous posting have mated very nicely with the Arduino Mini Pro. The first photo shows the side with the Arduino.

PCBs for the satpack project arrived from BatchPCB.com about three weeks ago. These are designed to mate with the appropriate pins on a Arduino Mini Pro , and to provide that Arduino with access to the realtime clock, piezoelectric speaker, buttons and  mini-din 8 connector required to control a recent Yaesu radio. To the right is one side of the design, the critical side that mates onto the Arduino. The boards are made from this design , but it ought not to be used, due to the errors described below.