Hayward design broadband low noise preamp for loops
 

On Sun, 13 Apr 2014 09:54:23 +0000 (UTC), "Geoffrey S. Mendelson"
wrote:

- If you're doing HF (2-30 MHz), you don't need a low noise front
end, and you certainly are going to need a high IP3 amp.

To be exact, I am looking for MW broadcast using the loop.
and lower HF bands (80m/40m/6mHz SWBC) using a short antenna, similar to
a PA0RDT type (in only that it is a short wire/pole connected to an
amp).

The PA0RDT design is a "mini-whip" not a loop.
http://dl1dbc.net/SAQ/miniwhip.html
Very different. Could you be more specific as to what you're trying
to accomplish, and what you have to work with?

Meanwhile, I suggest grounded base. (My thanks to MikeK a.k.a. amdx
for the references). I've built similar amps but never realized where
they originated. The big advantage of grounded base is that it's very
very very very stable.
http://www.thegleam.com/ke5fx/norton/norton_rohde_lankford.pdf
http://www.thegleam.com/ke5fx/norton/lankford.pdf
http://www.google.com/patents/US3891934?dq=3,891,934
Details. Note that the design was not made for an HF receiver amp:
http://www.cliftonlaboratories.com/norton_amplifier.htm
11dB gain. +50dBm IP3. 100mw out at 1dB gain compression.
Wheeeee... You could probably use it as a QRP transmitter.

More later. I'm rather busy today.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Hayward design broadband low noise preamp for loops
 

On Sunday, April 13, 2014 4:54:23 AM UTC-5, Geoffrey S. Mendelson wrote:
Jeff Liebermann wrote:

Thanks Jeff, (and the others that responded)

Summary:

- If you're doing 60 KHz with a loop, you don't need a low noise

front end and you might need a high IP3 amp.



Not 60hZ, nothing here at that frequency, nor 50kHz EU signals.





- If you're doing HF (2-30 MHz), you don't need a low noise front

end, and you certainly are going to need a high IP3 amp.



To be exact, I am looking for MW broadcast using the loop.

and lower HF bands (80m/40m/6mHz SWBC) using a short antenna, similar to

a PA0RDT type (in only that it is a short wire/pole connected to an

amp).


I've never needed a preamp for any of my multi turn MW loops.
I can see how you might need one for a very small single turn loop..