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Radio Road Which tuner to get and getting the most from it. Thank God, for the radio! |
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Radio Road Which tuner to get and getting the most from it. Thank God, for the radio! |
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A friend of mine recently gave me a Lafayette LT-D10 AM/FM tuner (circa mid 1970s) which has an unusual (to me, anyway) FM antenna connection feature.
As shown in the picture above, there is a movable "hook" which can be swung into place, to bridge the INT. (assuming that's "internal") with the EXT. (external) FM antenna connection.
I did an extensive search for the owners manual, without any luck. I did manage to find a schematic for the Lafayette LT-425T tuner (a portion of which is shown below) which has what appears to be a similar bridgeable connection.
Assuming Lafayette used the same connection for both tuners, is the intent to use the AC cord as an FM antenna when bridged? That's the best I could come up with, anyway. And if so, C5, the 1000 pF cap (which I've marked with a red arrow) seems to be the only thing blocking AC from the antenna.
This tuner is old enough that it doesn't have a polarized AC plug. When plugged in I check 123 VAC (my wall voltage) at the ground point on the back of the tuner, and about 3 VAC when the plug is reversed.
Bridged, the tuner does pick up more FM stations than unbridged, with no external antenna, if anyone was wondering. Unbridged, with an attic Yagi obviously is much better.
My two questions are:
1. Does my idea that the AC cord can be used as an FM antenna seem plausible?
2. Assuming the antenna connection on my LT-D10 is the same as the LT-425T schematic, is the 1000 pF cap the only thing keeping AC off the chassis? There's no UL approval label in sight, so I'm curious.
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Topic - Curious antenna connection on Lafayette LT-D10 - 1973shovel 09:09:22 05/07/19 (10)
- Quite common actually - Awe-d-o-file 14:23:19 05/09/19 (3)
- You can put away your red pen - 1973shovel 08:22:02 05/10/19 (2)
- RE: You can put away your red pen - Awe-d-o-file 12:41:30 05/11/19 (0)
- RE: You can put away your red pen - Awe-d-o-file 08:46:13 05/10/19 (0)
- RE: Curious antenna connection on Lafayette LT-D10 - Eli Duttman 10:21:59 05/07/19 (5)
- Dangerous even without the capacitor - Triode_Kingdom 17:26:06 05/12/19 (0)
- "That thing is DANGEROUS" - 1973shovel 07:50:00 05/08/19 (3)
- Not to worry...mostly.... - Steve O 09:46:15 05/08/19 (2)
- RE: Not to worry...mostly.... - Awe-d-o-file 14:30:29 05/09/19 (0)
- Thanks Steve - 1973shovel 10:49:00 05/09/19 (0)
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