Hello,
I’ve used my FSH4 spectrum analyzer (3.6 GHz version) for many years. I’ve found that while the supplied Garmin GPS accessory for the FSH4 allows it to access GPS satellite information, the FSH4 does not use it to synchronize its internal frequency reference with the information provided by the GPS signal (as verified using a second spectrum analyzer with its own GPS-locked external reference). Consequently, I’ve always had to use an external 10 MHz reference signal input to the FSH4's accessory BNC connector whenever I needed accurate frequency calibration with this instrument. Without doing this, the instrument internal frequency accuracy is only good for a little better than about 1 ppm.
This is strange, because the FSH4 manual states that the instrument is supposed to sync frequency with the GPS system when the antenna is connected, it is even supposed to remember the correction parameters for a day or so after the antenna is disconnected.
Could someone please assist me as to whether I may not have configured the instrument settings correctly? I am a retired electrical engineer.
Thank you for any suggestions!