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Input antenna attenuation?

 

Having a reception issue. I was wandering what voltage/power I could dump into the antenna bnc port safely. Ie I want to inject a 7.1mhz tone into a bitx40 to trace the signal around the board.?
 

-73 dbm is S9 signal, so go a lot lower than that.

73

Ken VA3ABN

On Wed, Apr 26, 2017 at 8:52 AM, <stronggeek30s@...> wrote:

Having a reception issue. I was wandering what voltage/power I could dump into the antenna bnc port safely. Ie I want to inject a 7.1mhz tone into a bitx40 to trace the signal around the board.?
 

On 27/04/17 00:52, stronggeek30s@... wrote:

Having a reception issue. I was wandering what voltage/power I could
dump into the antenna bnc port safely. Ie I want to inject a 7.1mhz
tone into a bitx40 to trace the signal around the board.
Don't do that. Trace it from the other end.

S
 

Check out Farhan's blog regarding receiver checkout. ?? ?He's using a piece of insulated wire just a few feet long to pick up local qrm for injection into various parts of the radio. ?Most of us have plenty of that around (wire and qrm both).

We've had several posts about how Q13 will blow if you have a QRO transmitter on a nearby antenna. ?Adding a couple 1n4148's back-to-back from K1-12 to ground keeps received signals down to a max of 0.7 volts to ground, is apparently sufficient protection. ? I'd think injecting up to 100mv pk-to-pk at the antenna should be safe enough, though at that level the other end will be getting overloaded. ? There's not much cumulative gain till you get into the audio amp at Q16, as the mixers and filters all have their losses.

Jerry, KE7ER


?

On Wed, Apr 26, 2017 at 02:42 pm, Steve Wright wrote:



Having a reception issue. I was wandering what voltage/power I could
dump into the antenna bnc port safely. Ie I want to inject a 7.1mhz
tone into a bitx40 to trace the signal around the board.
Don't do that. Trace it from the other end.

?
 

Thank you everybody :) i shall have to probe around knowing what i can safely dump into the signal path. it will have to wait for the weekend :( overtime at work is calling. I hope to report success soon.

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