Monday, February 12, 2007
Got the TenTec 238B High Power Antenna Tuner and an MFJ dummy load into the shack this evening.
Time to play with the antenna tuner and my current antennas.
A couple interesting discoveries.
It was funny discovering the feedback between the rig's SWR protection circuit and the tuner as I was dialing things in. As the tuner was tuned better, the SWR would go down, allowing more power through and generally messing with the metric that I was using to judge "success."
Once I figured out what was going on I could compensate, but things were really weird for a couple of minutes... ;-)
All in all a good evening. It will take one more evening to formally characterize the antennas and create appropriate "cheat sheets."
Once I have that down it will be time to lay in...
(crack of thunder and organ music)
.. the amplifier.
Time to play with the antenna tuner and my current antennas.
A couple interesting discoveries.
- My rig's SWR protection circuit will "fold back" the power to about 10W.
- It takes about 30W to get the 238B's SWR meter to set correctly.
- The 238's tuning procedure assumes that its SWR meter is set correctly.
- Things tune easier if you understand what the instructions REALLY say to do when the best match is obtained when the capacitor is set to zero. (Go to the other side of BYPASS)
- The G5RV Jr REALLY sucks on 30m (I knew that, but rediscovered it).
- My 80m EFHW inverted-U tunes pretty well on 30m (I didn't know that)
- Next time I'd rather play with the antenna tuner using an antenna analyzer rather than my nice expensive rig...
It was funny discovering the feedback between the rig's SWR protection circuit and the tuner as I was dialing things in. As the tuner was tuned better, the SWR would go down, allowing more power through and generally messing with the metric that I was using to judge "success."
Once I figured out what was going on I could compensate, but things were really weird for a couple of minutes... ;-)
All in all a good evening. It will take one more evening to formally characterize the antennas and create appropriate "cheat sheets."
Once I have that down it will be time to lay in...
(crack of thunder and organ music)
.. the amplifier.
