|
Posted by Ed Holland on June 05, 2023 at 19:52:57.
In Reply to: LF isolating transformers posted by Ed Holland on May 29, 2023 at 17:42:23.
More experimentation on the matter of transformers. Another scan of LF suggested that perhaps the system was not delivering quite as well as it had with the original transformer. There was definitely some common mode noise, at a level comparable with that obtained using the dipole antenna <100 kHz and which is configured for HF.
A new transformer was wound, doubling up on the primary and secondary turns. (24:8 T respectively). This improved signals considerably, WWV being much clearer than when the 12:4 turn design was in place. It's a challenge to get the required mutual inductance, but it can be done. Expectedly, the HF performance has been somewhat reduced, but seems quite useable up to 20 MHz, although this hasn't been explored with any rigor. A check on 80m, and AM broadcast band showed performance to be excellent. Too good perhaps, as one AM local sent the signal meter on the JRC all the way over to its maximum reading segment. 73s Ed
|
Follow Ups:
|