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Re: Using a nanoVNA to test a transmitter #newbie #general_vna


 

On 2/14/21 10:19 PM, David McQuate wrote:
Yes. 5W is +37 dBm. This attenuator can handle 5W continuously, and its 41 dB attenuation will reduce the transmitter signal to -4 dBm. The TinySA max input power is +10 dBm with its internal attenuator set to 0 dB, so you are ok. Using more attenuation in the TinySA might be prudent. Note the qrpkit attenuator upper frequency limit is 200 MHz. Its attenuation will probably be reduced at higher frequencies.
Dave

Cierra <dubosec@...> wrote:


they have some other attenuators that might be more suitable (and cheaper) - you might look at the single T attenuator or at the dummy load. (I worry about a switched attenuator - if you accidentally forget to switch it, poof goes your SA)

That dummy load, which has a diode detector, looks interesting. What I would do is take a 50k noninductive resistor in series with the SA input and hook it to the 50 ohm line on the input of the load (making a 1000:1 voltage divider with the input Z of the SA).? That will give you about 60 dB of attenuation, putting your 5W at -23 dBm

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