Saturday, September 5, 2009

New 2nd-Hand Toy: FRG 100 (aka Frog 100)

Finally, I could not resist. For various projects, e.g. 136kHz, I bought a 2nd-hand FRG 100 at my not so local "radio boer".

Seems it's got the FM option built in, however, no cw-filter and no tcxo.

According to the RSGB publication "LF Today",the receiver is as sensitive on 136kHz as the TS-850's receiver. This claim actually made me buy the Frog 100.
"LF Today" further reports on the modification of the SoftRock lite ( for low frequency use. More on that in a further entry.
However, I like the pointer to the SoftRock lite, since my plan was to include a SoftRock lite into the Frog. There is room enough in the casing,the second i.f. is 455kHz, thus, using a 1.8432MHz crystal in the SoftRock lite, resulting in a center frequency of 460.8kHz, will add a nice I/Q-SDR back-end to this nice piece of kit.

The lack of cw-filter could possibly solved by a 455kHz ceramic resonator ladder. I'll see about that.

Last point, the missing tcxo, that is a bummer really. Three ways to go, leave it as is and hope the best for stability, try to hunt down a tcxo (could be a tough one) or build a temperature controlled oven around the existing xtal.

Finally, I wonder if I could use the meeaouw port (c.a.t.-flap) for something meaningful...