measure receiver sensivity

Hi , I have a 434MHz receiver ( ASK ) with an helix antenna , I want to measure sensitivity of my receiver , I have a spectrum analyzer .
another question is : how can I measure the transmitter power , because I don't know the output impedance of my transmitter and the antenna of the transmitter is looking like a microstrip and I want to know how should I connect the probe to my board because my board hasn?t any connector
thanks a lot

a spectrum analyser isnt going to be much help testing receiver sensitivity
what you need is a calibrated signal generator, for 400 MHz area an IFR1200S would be ideal it covers 400MHz and up to 1000MHz
The IFR1200 also can read power levels up to 150 Watts

You could feed the TX into the spectrum analyser with the appropriate attenuation to protect the analyser. It will give you an accurate power output, assuming its calibrated

you could solder a coax lead off the board and have a connector on the other end of it suitable for your test gear

cheers
Dave

Instead of using your transmitter not having an access to its output connector, I would simply build an oscillator and connect a dipole antenna to it. Or, use a signal generator with a calibrated RF output. You can easily measure the RF power, and you can estimate dipole gain (or take it as one dBi). Then you can vary the distance between the TX and RX antenna, calculate the appropriate propagation loss and determine the RF power reaching RX antenna for changing the output from LO to HI as the system is ASK.
There will always be some error due to surrounding objects and earth, but this is the real world.