[AMPS] RF pre amps for VLF

[nospam4me@juno.com]

: From: "Tom Tishken KD4WOV" <kd4wov@earthlink.net>
: Has anyone any experience or schematics for preamps for 
: VLF around 110khz to 190khz?

Hi Tom, 

Yes, send my your Mailing Address and I'll pop you off a photo copy 
of a nice one.  It would be worth your while to try and find a copy of 
the Low Band Experimenters Handbook by an East Coast Ham who 
I believe is now an SK    :-(        Great book to have around. 

: Any thoughts about simple preamps with a tunable preselector and gain
: controls? 

I "lifted" one preamp design from a 1987 Motorola Loran C 
Automatic Vehicle Location  "AVL" unit I often serviced.  You need 
lots of gain to dig out 100KHz    GPS has pretty much killed 
regular Loran C applications. 

: Any thoughts about HF monoband preamps?
: Any thoughts on HF mono band preamps with a very narrow bandpass to
: eliminate blanking due to high power SW stations?

A lot of "Loafers" prefer highly directional antennas... loops and all
that 
type of thing. 

: In contesting has anyone used preamps with AGC?

I gotta laugh at this one... rf wise, contesters often have AGC and 
compression, but the proper operation of is often in question by 
others on the band. 

: Last question:
: Has anyone used negative feedback with transistor amps 
: for better linearity?

Yes, but you might want to be more specific...

cheers
skipp 

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