[Melb-ARDF] RE: [ARDF] Some information about Ukrainian Radios, I think...

[Marvin Johnston]

First, I might point out that there are two Ukrainian receivers built by
two different people. The only difference I can see between the two is
that one is black and one looks to have a light green anodizing. The
light green one is the one built by the M50 competitor from the Ukraine.

bruce wrote:
> 
> > Receiver 144 MHz.
> > Receiver has two passbands IF amplifiers, switched by the toggle
> > switch,: wide -100 kHz and narrow of 15 kHz.
> 
> Looks like the more advanced one also has a whoopee (tone generator) which
> they recommend using. I don't really understand the 'threshold detector',
> but it sounds like it enhances the peak by doing something audible to the
> received tone, and this effect tapers off as you get really close.

>From what I can read (and guess having used a similar unit), the
"thresold detector" is the whoopie mode. The tone mode is not a whoopie
mode, but rather a constant tone that increases in volume with the
strength of the signal. The tone mode is supposed to be more sensitive
than the whoopie mode, and that is my experience.


> The preset buttons appear to bypass the gain control with preset gain
> settings, pretty much like the fixed ranges on the Mk4, or the selector
> switch we have on our 80m sniffers. We just do away with the continueously
> variable gain control altogether !

Pushing the "50M" or 200M" preset switches put the receiver into tone
mode with the attenuators set so the tone can be heard if there is a
signal present at 50 meters and 200 meters respectively. Of course, this
will also depend on the transmitter power output. I'm not sure what they
are calibrated for, but I would guess about 1 watt. The gain control
will still work as expected.