Discussion in '"Boat Anchor" & Classic Equipment' started by KB1RHB, Dec 10, 2019.
The Counterpoise should not be inside of the shack.
The best tool I have for my portable as well as shack operation is a RigExpert AA-54 antenna analyzer. It answers a lot of questions and sees problems before they damage any of my rigs. Antennas sit outside in sometimes harsh conditions and they can change from one day to the next--one storm to the next. The analyzer "sees" what the antenna looks like to the transmitter at any frequency. Yes, they use the antenna at a small fraction of the actual operating power, but they are great indicators of how successful you will be matching the system up.
This is what I see with VNWA. Odd I do not see significant peak, Q, at its resonant point, which for 130' should be around 3.7 Mhz.
Antenna is 20' off ground drive end, ~ 60' far end, longwire, no radials, ground snow covered.
Does it look approximately right ?
Looks like I have some challenges in the radio -
Tuneup, Dummy Load all
Where is the plate current sitting during those adjustments?
It looks like the driver tube may be weak and/or the radio could use a coil pack adjustment.
Looks like signs of weak drive.
Maybe just the driver or alignment.
You beat me to it.
May be a coil pack problem.
Plate current -
There's more than a driver alignment (i.e. coil pack) problem. Something in the finals tuning and loading is not right.
For instance on 160m: 200 mA at 800V implies 160 watts DC power input to the finals and at normal 60% efficiency for a Kenwood hybrid that would translate to 96 watts RF output but you're only seeing 65 watts. Other bands are even more extreme. For instance on 20 meters you should be seeing 105 watts RF output based on that plate current reading but you're only seeing 20 watts.
I haven't gone back through the thread but did you check the value of the cathode resistors which should show 5 ohms in their parallel combination? If those are off then all your current metering including metering of bias current will be off. If those are right then I'd suspect output coupling problems which could be a bad relay or relay socket, a bad connection between the finals and the relay or the relay and the antenna connector or possibly a bad output coupling capacitor or RF choke in the finals stage.
Here's some info on common problems in the Kenwood hybrid finals stage and how to fix them: