What is the mW output from "blown" RDVV driver?

Elopid · Post by **Elopid** » Mon Mar 22, 2021 1:03 pm

Hi guys,
A strange question for you now. So a few years ago my friend put an RDVV 8w driver up a hill in a tree and it was putting out a good signal, but the RDVV was left over time up in the tree and the yellow trimmers got damaged from the moisture/ weather which caused a direct short resulting in the 2SC1971 to blow.
But there was still a weak signal coming out into the antenna because we could still hear the signal weak for a few miles so I am wondering what kind of power would have been leaking through the blown 2SC1971 because we still picked up weak signal from with the blown transistor.

yellowbeard · Post by **yellowbeard** » Mon Mar 22, 2021 2:03 pm

BFR96 isn't it? That's about 300mW but I have no idea how much of it will leak past the 2SC1971. If you are doing that again silicone sealant or PVA glue slathered on it will slow the damp down. If it's a permanent arrangement, mummify the whole thing in denso tape - it's great stuff, I want to be wrapped in it when they bury me...

Albert H · Post by **Albert H** » Mon Mar 22, 2021 2:33 pm

Are you sure that the 1971 was dead? It's possible that it was still working, but into a really bad match because of the orroded trimmers.

The reason I ask is because I had a 1971 on 62 MHz in a link rig, that was operated for several days without an aerial on the far end of the coax - most of the aerial blew away in a storm, but the link continued to work, albeit with a worsened signal to noise ratio!

Elopid · Post by **Elopid** » Mon Mar 22, 2021 3:28 pm

Hi guys thanks for the swift replies.
Yes I am 100% sure that the 1971 was blown because the input pin was showing around the same power as the output pin when we RF probed the 1971. We changed the 1971 and it lasted 2 seconds and blew again and that's when we realised there was a short on the output trimmer. But yeah the power was around the same going in as coming out after they blew but we just didn't measure how much it was.

radium98 · Post by **radium98** » Mon Mar 22, 2021 4:03 pm

@Elopid what a sad story , you know theses days the 2sc1971 is a piece of gold

can you share some pictures of the transmitter

thanks

Electronically · Post by **Electronically** » Mon Mar 22, 2021 4:18 pm

Hmm that's odd I had a problem with a Bfr91a before. Seller was 100% sure it was working. I didn't even have it in the board yet I could test it was shorted. So to save along arguement I pulled out another Bfr91a from another seller. Voila it was working.

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What is the mW output from "blown" RDVV driver?

What is the mW output from "blown" RDVV driver?

Re: What is the mW output from "blown" RDVV driver?

Re: What is the mW output from "blown" RDVV driver?

Re: What is the mW output from "blown" RDVV driver?

Re: What is the mW output from "blown" RDVV driver?

Re: What is the mW output from "blown" RDVV driver?