[Lowfer] " XR's " first WSPR weekend

[Andy - KU4XR]

John:  Link to the PA schematic:

http://ku4xr.webs.com/apps/photos/photo?photoid=108936955

I'm sorry, when I try to explain what I'm doing, it's all too
easy to get mW, and mA interchanged in my typing.

As it should be, the reference is to MilliAmps of RF Current,
and not MilliWatts...slip up on my part;




Andy - KU4XR - EM75xr - Friendsville, TN. USA

LOWfer Beacon " XR " 
 
--- On Mon, 12/6/10, John Andrews <w1tag at charter.net> wrote:

> From: John Andrews <w1tag at charter.net>
> Subject: Re: [Lowfer] " XR's " first WSPR weekend
> To: "Discussion of the Lowfer (US, European, & UK) and MedFer bands" <lowfer at mailman.qth.net>
> Date: Monday, December 6, 2010, 4:02 PM
> Andy,
> 
> > *** How ever accurate the power test may be; the meter
> shows
> > 1-1/2 watts output into the 50 Ohm dummy load MAX, and
> distorted,
> > using a 1500 cycle tone. For a clean output, it shows
> .75 watts .
> 
> That's 17 volts peak to peak across 50 Ohms. That's more
> than enough to 
> drive any 1 watt Class D. PA. Did you have a 50 Ohm
> termination at the 
> input of the PA? Is there a schematic of the PA available?
> 
> > I can connect the radio directly to the 50 Ohm LPF,
> and see
> > 60 mW of RF current on the RF ammeter running wide
> open........
> > I connected the radio output thru a .33µF cap to the
> input of the
> > Class " D " amp, and got 90 mW of RF thru it..
> Disappointment !!
> 
> Are you doing a calculation to get those mW readings from
> the antenna 
> ammeter, or are you talking about the antenna current in
> mA?
> 
> John, W1TAG
> ______________________________________________________________