[Lowfer] Beacon DIR on the air...

[Bill Ashlock]

Jim,

Are you sure that it is 9 ma? This would be .09v (90mv) measured across a 10 ohm series resistor. Check things out by NOT using a matching coil - just a loading coil in series with the antenna and your final. If your antenna + loading coil Q is up to par you should see a lot more current going into the final at resonance.

Bill

> From: w4jbm at bellsouth.net
> To: lowfer at mailman.qth.net
> Date: Sat, 3 Oct 2009 12:58:14 -0400
> Subject: Re: [Lowfer] Beacon DIR on the air...
> 
> > > The final is a slightly modified LEK design. It's operating at 11
> > > volts and pulling 9 mA (measured at the xmitter).
> >
> > Any hope of getting it up to full power?
> 
> I can crank the voltage up a bit without things overheating (I'm using a 12 
> volt supply and have a diode in-line for protection, so between that and 
> line-loss I'm down to the 11 volts). I've tried different taps on the 
> matching coil and this is where I get the best signal strength. (I can draw 
> more current going closer to ground, I just see the near field signal 
> strength drop instead of rise when I do that.)
> 
> I think the fundamental problem is that the antenna impedance is too low and 
> I'm not able to get it matched at all. Building an RF current meter and also 
> looking at something like a 1:3 RF transformer are on the to do list.
> 
> So the short answer is that I think I'm down 10 dB for now. Or maybe a 2E26 
> would load up better. :-)
> 
> 73 de
> Jim W4JBM
> 
> Receiver - Ten Tec RX320D
> Antenna - Butternut Vertical (SW) and mini-whip (LF)
> Location - Bowdon Junction, GA  USA (33.6581,-85.1249 EM73)
> 
> http://www.hamuniverse.com/w4jbm/
> 
> "With a soldering iron in one hand, a schematic in the other, and a puzzled 
> look on his face..."
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