Re: 50W PA Damaged


geoff M0ORE
 

I don't think any ATU will prevent damage to a transmitter due to human error. The commercial and military  equipment employ extensive circuitry in the transmitter to take care of such mishaps and shut down to a safe level. A soldier under fire can be forgiven for not checking the aerial matching. Likewise, an aerial on a vehicle may be damaged without the operator being aware of the damage.

An ATU is basically a means of transforming one impedance to another. If no load is connected i.e. a very high impedance, then that is reflected back through the ATU to your transmitter as a very high impedance. Hence the blown finals.

You could design an interlock system such that if the aerial is not connected the transmitter does not power up.



On 30/05/2020 11:28, George Korper wrote:
Usually, it is just the finals. That has been my experience in the same exact circumstance. 

On Sat, May 30, 2020 at 2:22 AM J P Watters via groups.io <kc9kko=mac.com@groups.io> wrote:
I think this will be me at some point. 

My thought is to install a ATU like this one to protect the finals from transmitting into an open antenna.SDR rig to protect the finals. 
https://github.com/Dfinitski/N7DDC-ATU-100-mini-and-extended-boards
Will that ATU provide that kind of protection.

..jpw J P Watters
KC9KKO





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