[AMRadio] DX-100B Low Output on 15/10 Meters - Update

Mark Bell bell at blazenet.net
Mon Oct 25 19:14:22 EDT 2004

Thanks to all that sent me emails.  Most recommended spreading the 10/15
Meter loading coil, so that's what I did.

I'm now getting around 100W output on both 10 and 15 meters.  The tune up is
fairly picky;  pick the wrong Ip dip and the power output drops quite a bit.

I noticed that when the power output was around 100W carrier,  it would drop
to 60W or so on voice peaks (modulator current around 125 to 150 mA).  This
happens on both 10 and 15.

If I reduce power to 50W carrier, there is no power drop during modulation.

I checked all my tubes, and they all test in the green.  Yep, I know I need
to SS the rectifiers.....

So, I get on 10M AM yesterday, and have 2 really nice long ragchews.
Carrier output is 100W, and power output on voice peaks is about the same!!

Maybe the DX-100B is a lot more pickier than I thought on 10 and 15, but it
worked like a champ yesterday, and I got great audio reports!

Any comments as to why I saw the drop off in power when the signal was
modulated?  If anything, I expected to find a soft rectifier tube.  Also,
the drop in Ip and Ep associated with the drop in power was about 20 mA and
20V respectively; certainly not enough to account for a 40W drop in output

73 Mark K3MSB

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