On Dec 19, 10:14*am, Lostgallifreyan wrote:
Does anyone know what the Sangean ATS-909's external antenna input impedance
is?

I searched for days for documentation on that radio and found plenty, mods,
schematics, service manuals, reviews, but no straight word on the impedance
of that input! (Not even in the service manual specs). The only reference I
found was a from a guy on a 7-page set of ham reviews, and all he said was
that it was a mystery!

Maybe the only way to know is to start from the schematic but I don't know
how, but here's the best schematic I could find:http://eric.horsemensociety.info/TEC...chematic_A.gif
(Antenna input is near top right).
(Link appears to be dead, 403, forbidden. I'm sure it worked last week..)

What I really want to know is whether the ATS-909 will work ok with a
long(ish) wire outside feeding a 50 ohm coax via a 9:1 transformer, or if
that would cause more bother than connecting a wire directly to it and
putting up with local noise picked up from nearby buildings.

Ive measured the input impedance of a few SW receivers and found them
to be in the 1Kohm ballpark for the most part. I did this by applying
a voltage through a series resistor to the frontend of the radio and
adjusting the value of the resistor until the voltage dropped by 50%.
If you have a schematic an analysis of the front end circuit might
give you and idea.

Jimmie