[Test-Equipment] Information needed RF meter

[J ALLEN CALL]

Hi Robert:  OKay.  Here is what I am doing.  I have an AM transmitter rated at 100milliwatts on 1620Khz.  It is connected to a 8 foot vertical antenna, with a loading coil and variable capacitor, and I would like to connect the meter so that I can adjust the loading coil turns and capacitor for maximum output.  I know that I can use a scope but I need this to be portable.  What I am trying to do is demonstrate a recording that I have with President FDR giving his December 8, 1941 talk to the nation about the Japanese bombing of Pearl Harbor and declaring war on Japan.  I have a Hallicrafters SX28A  tuned to 1620Khz so that the broadcast can be heard using the 1941 era receiver.  The transmitter is so close to the receiver that it pegs the S-meter which is why I need the milliwatt RF meter.  Any suggestions?  

 

J

W7KSG 
.
 



 
> From: WA5CAB at cs.com
> Date: Tue, 20 Oct 2009 19:52:02 -0400
> To: test-equipment at mailman.qth.net
> Subject: Re: [Test-Equipment] Information needed RF meter
> 
> Jay,
> 
> The answer is that more information is needed. If the RF source is 
> something like an exciter, rated for example to output 100 mW into a 50 ohm load, 
> and you want to connect an indicator to see whether it works properly or not, 
> then how to do that depends upon whether it is connected to its intended 
> load or not. If not, you need a dummy load watt meter (or milliwatt meter). 
> If the intended load is connected, you need an RF voltmeter. The two can be 
> substantially the same circuit wise, but component values will differ by at 
> least one and better two or three orders of magnitude.
> 
> In a message dated 10/20/2009 6:29:47 PM Central Daylight Time, w7ksg at q.com 
> writes: 
> > I need a meter to measure 100milliwatts of RF. I was wondering if I 
> > connect the RF source to a 0-200Ua DC meter and put a diode in series with the 
> > plus of the meter to change it to DC would that work? Would it be sensitive 
> > enough to get a reasonable response on the meter scale? I know that it 
> > will not be calibrated. I just need an output indication. Any ideas out 
> > there? Thanks.
> 
> Robert Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480
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