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Old March 27th 05, 03:11 AM
Pete KE9OA
 
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It is just a single tuned circuit, where I am tuning the primary of the
loopstick, with the secondary winding driving the amplifier.
With the MMIC I use as an RF amplifier, overload isn't an issue. The RFMD
RF2044 can put out +17dBm of linear power into 50 ohms............1dB
compression doesn't occur until +18.5dBm. It looks like this device is
discontinued, so I need to find another one. I've got around 400 of the
2044s on hand, but for a production run, that isn't quite enough.
For the input stage, I am going to switch to a differential JFET design.
This should help in achieving deep nulls with the antenna. Although I have
been building different iterations of these antennas, the balanced design is
new for me.............I do see advantages with this approach, so I will be
going in this direction for a marketable item.

Pete

"starman" wrote in message
...
Pete KE9OA wrote:

Aperture is exactly the point I was going to get at.........this is the
reason that the receivers I have built that use the Mini-Circuits mixers
as
the first stage have worked very well with an 8 foot diameter untuned
loop.
No IM products anywhere in the LW/MW bands.


What kind of preselection design do you use ahead of the first mixer
stage?

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