Personal experience with ARR, they are superb. Tried MFJ, not too happy with the result there

Mark Lunday WD4ELG Greensboro, NC - FM06be wd4elg@arrl.net http://wd4elg.net http://wd4elg.blogspot.com

-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Gary "Joe" Mayfield Sent: Thursday, November 26, 2009 2:46 PM To: 'Michael Chen'; 'amsat-bb' Subject: [amsat-bb] Re: 70cm preamp

Hard to beat ARR

http://www.advancedreceiver.com/page10.html

73, Joe kk0sd

-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Michael Chen Sent: Thursday, November 26, 2009 1:04 PM To: amsat-bb Subject: [amsat-bb] 70cm preamp

HI, All,

I am looking for a good 70cm preamp for satellite operation. Kind of urgent. Recommendations and sale are welcome.

Michael Chen, BD5RV/4 Email: michael.bd5rv@gmail.com MSN: bd5rv@jsdxc.org Skype: michael-bd5rv _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

----- Original Message ----- From: "Glen Zook" gzook@yahoo.com To: "amsat-bb" amsat-bb@amsat.org; "Michael Chen" michael.bd5rv@gmail.com Sent: Friday, November 27, 2009 1:22 AM Subject: [amsat-bb] Re: 70cm preamp

Ramsey actually has a pretty good low noise preamp for 70 cm and those are

cheap. Takes about 15 minutes to assemble the kit. I do recommend replacing the fixed capacitor across the coil with a variable. That way you don't have to "fiddle" with bending the coil to tune it. You just "set" the coil and then use the variable to adjust the actual frequency.

I bought one of the 70 cm kits and one of the 222 MHz kits several months

ago. Both of them work very well. The 222 MHz has a slug tuned coil but the 70 cm is fixed and you are supposedly to tune it by moving the turns around. But, MUCH easier to adjust if you replace the fixed capacitor with a variable.

I am almost sure that they ship internationally. The kits are less than

$15 U.S.

Glen, K9STH

Website: http://k9sth.com

Hi Glen, K9STH

But how do you adjust the input of your low noise preamplifier for the lovest Noise Figure ?

To do that you cannot just "set" the coil and then use the variable to adjust the actual frequency for maximum output but you need a Noise Source and adjust the coil and the variable for the maximum S/N ratio and this can be done manually or automatically using a Noise Figure Meter.

This is why to build a low noise preamplifier without to have a Noise Figure Meter or a SINAD meter is like to walk blindly.

73" de

i8CVS Domenico