Hi everyone,
Thanks for all the replies on the LK500, everyone seemed to converge on the
same area to check out. I'm in the process of replacing the parasitic
suppressor resistors.
While I wait for parts....
Background: I've mostly finished up my solid state amp based on the MRF141G
using Motorola app note AR313. One of my original design goals was 160 - 2
meter operation & 70cm, but that is another PA strip. As it seems to be
turning out, it's basically impossible to make 9:1 and 1:9 input/output
transformers which work over that broad of a range. The transformers I have
work accoring to the app note, but that doesn't give any performance on 160,
80, and 40 meters.
Solution: Remove the original matching transformers and replace them with a
circuit board with two input transformers and two output transformers and some
relays to switch between them. The difference between the transformers would
be the permability of the core material one in/out set would be for lower
frequency operation, the other for higher frequency operations. I've drawn
up a simple schematic showing the switched input and output transformers.
http://home.comcast.net/~kg7hf/Project2/MRF414G_TEST1.JPG
Does this seem like it would be workable, assumeing lead lengths are all kept
short? Is there any way to reduce the number of relays? I was possibly
thinking about combining RL2 and RL4 since only half is used on each.
Thanks,
Paul KG7HF
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