Hi Eric,
I have decided to use an SO-239 for the low impedance input. For
the high impedance input, I will be using a Mini-Circuits 4:1 transformer.
The good thing about this approach is that the high impedance can come in at
the transformer input while the low impedance can come in between either one
of the balanced inputs and ground, the same way it is done in FM tuners.
This way, the low-pass image reject filter doesn't get perturbed. This also
eliminate the necessity of having an external matching device (believe me, I
considered this avenue!).

Pete

"Eric F. Richards" wrote in message
...
"Pete KE9OA" wrote:

I am finishing up the MW receiver..............anyway, I have a high
impedance antenna input in addition to the 50 ohm input. With this type
of
receiver is the high impedance input enough, or would interested parties
rather have both inputs.
The reason I am asking this is because my employer would like to have all
jacks mounted to the main PC board. The only thing I have been able to
find
so far has been a right angle BNC connector for the 50 ohm input.
Opinions welcomed!

Pete,

I'm in favor of the low-Z input myself. I wouldn't want to connect a
"wire" to any receiver without some robust -- and sacrificial --
isolation.

Would your boss be in favor of using (or recommending one of the
existing) an external impedence matching device with binding posts on
it?

Pete


Eric

--
Eric F. Richards

"Nature abhors a vacuum tube." -- Myron Glass,
often attributed to J. R. Pierce, Bell Labs, c. 1940