SpamHog,

Here's another question:

I've been building the Desert Ratt 2 today, starting with the audio amp.
Problem is that I am getting attenuation rather than amplification.

I have questions about the biasing network surrounding Q4. R9 and R10
are specified as 1.2K (1200 ohm). The schematic states that the
emitter and collector voltages should be 3.0 Volts. However, my version
develops an collector voltage of 7.2 Volts and an emitter voltage of 1.7
Volts. My base voltage is 1.8 Volts (which is in the ballpark of what
the schematic states as should be 2.0, I am not nearly as worried about
that one.

I had used a 2N3904 as recommended. On the assumption that the
transistor could be bad, I subbed a 2N2222. Same result.

It seems to me there might be a misprint with respect to the values of
R9 and R10.

Any ideas?

The Eternal Squire

The Eternal Squire wrote:
Hi,

I have a question about the Desert Ratt 2... do you have any idea what
the dimensions of the form for the onboard coil are?

Thanks,

The Eternal Squire

SpamHog wrote:

The "Desert Ratt" is a clever design for a sensitive and well behaved
shortwave regenerative radio. It has been doing the rounds in various
forms since 1994, and quite a few people added new twists.

As I kept seeing roughly the same stuff popping up all over the place,
and found it somewhat hard to keep track of which version was an
improvement over another one, I did a bit of investigation to figure
out who did what, and what the direction of development was.

Read it all at:
http://webfools.net/filippo/desert-ratt.html

BR

Filippo/SpamHog
N1JPR/I2
http://filippo.ru.ru