Re: New assembled High Bands QDX went into smoke
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Dave and I have discussed this at length; there are a large quantity of chewed-up textiles from our discussions. To add to his comments,? his calculation below is based on 50 + 0i? ohms, which is a PURELY RESISTIVE load with a SWR of 1:1. Even if Z = 50 ohms, you can have V >> 47 V p-p if the load is reactive. If you want to play with the math, try calculating the impedance a 30 ohm resistive with first a 40 ohm inductive reactance then a 40 ohm capacitive reactance........................
Lee KX4TT
On Sunday, July 16, 2023 at 04:02:24 AM EDT, David Birnbaum <dbirnbau@...> wrote:
The relevant voltage is NOT 12V.? The RF voltage is over 40V.? For 5W into 50 ohms the voltage is roughly 47 V p-p.? If the SWR is greater than 1:1 the voltage goes up.? The BS170 has a max voltage of 60V, so it's running near breakdown
dave k2lyv
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Lee