31 May 2009

6m Lunchbox - further thoughts

Further thoughts on the G3XBM answer to the Benton Harbor Lunchbox for 6m. Maybe it would be better to make the rig DSB instead of AM? The design is almost as easy and a VXO crystal at 25.08 or close would give some 50kHz VXO range (50.15-50.20) in a useful part of the band. Also, it would be more efficient than AM. In sporadic-E openings it would produce some DX contacts too if the power out was around 0.5 to 1W pep.


Michele IZ8JJI said...

Hi Roger, DSB seems to be a nice idea. I've seen a very simple schematic of 6-10m transceiver (DSB transmitter-DC receiver) on the net (http://www.cqpub.co.jp/hanbai/books/15/15061/15061_p.180-181.pdf). Ok, is japanese language, but the schematic is clear and using google translate you may have some help (I've done in italian language).
The 2 bipolar transistor (2sc1815) seems to be for audio purposes (NTE database) and may be replaced easily (I think). The FET (2sk241) may be replaced with 2n7000/BS170 (I think). The problem come with coils, which are specialised like-IF cans for 10m or 6m bands, and I'm not able to retrieve them.
Do you think this schematic is useful for your purpose?

73 de Michele IZ8JJI
G-QRP# 12191

Roger G3XBM said...

Thanks for this link Michele. What an excellent circuit too!

Bill N2CQR CU2JL M0HBR said...

Roger: Your project reminded me of one of my own. I took a very dead Sixer and used the parts and the chassis to make an 80/40 meter superhet receiver using 6U8 tubes. It was a Lew McCoy design called "The Mate for the Mighty Midget."

So there is enough room in there for at least a DSB transmitter.

73 Bill N2CQR