Re: LF: Re: 500kHz

[ColePe@aol.com]

Another approach - as I have a number of crystals at the low end of 3.5 MHz and TTL devices in the junk box I built a 7400 oscillator feeding a 7490 decade counter wired to divide by 7.  Although the mark/space ratio of the 7490 output is far from ideal I was surprised at how easy it was to get a clean looking 500kHz sine wave with a very simple filter.

Peter, G3JFS

 

 

 

In a message dated 22/05/2007 10:03:24 Greenwich Standard Time, g3kev.ham@virgin.net writes:

It is so easy to get on 500.

RE-Easy Start

Xtal osc 5 mhz/div by 10/fet driver chip and fet pa in class E.

A couple of hrs to build from the junk box.

The psu can be the common 13.8v at a couple of amps max.

Keep it simple.

G3KEV

 

----- Original Message -----

From: lawrence mayhead

To: rsgb

Sent: Monday, May 21, 2007 2:58 PM

Subject: LF: 500kHz

Hi Vic,
Re. Linear Amp, have a look at design by SM0VPO (Ten Watt Linear Amplifier )
just Google, should find it.
I use his basic design just put a few more turns on inductors.
73 Hope see you on 500.
Laurie G3AQC.