FT-991 HF, 50, 144, 430 MHz All Mode – Yaesu USA Update the Firmware MAIN Ver. 02.02 – DSP Ver. 01.04 and TFT Ver. 02.01 of 24/07/2015 – See …news and linck below –
VA7OJ’, Adam Farson describes the Noise Power Ratio Testing, a 1st measurement in the Yaesu FT-991 only HF bands (for now!) – Receiver performance evaluation using notched noise, tune DUT (FT-991) such that the IF passband is centred in the notch. Calculate NPR using Equation: NPR = Ptot – BWR – MDS.
All the NPR measurements, by VA7OJ, Adam are performed in SSB mode, at 2.4 kHz bandwidth. The bottom of the notch in the noise generator (a Wandel & Goltermann RS-50 White Noise Generator ) bandstop filter is 3 kHz wide. Adam uses the 3 kHz roofing filter in the DUT (automatically selected in SSB mode in the FT-991 Transceiver)
A typical NPR test case emulates 1200 contiguous SSB signals, each at S9 + 30 dB. The higher the NPR figure obtained in the test, the better the DUT will be able to survive such extreme conditions. – The NPR test is also useful for identifying IMD choke points in a receiver front end, e.g. in RF steering diodes, and also passive IMD (PIM) in crystal filters, inductor cores and even some capacitor dielectrics.
I would categorise NPR ranges as follows: Measurement limit: ~ 95 dB (notch depth) / 85 dB and up: Excellent / 80-85 dB: Very good to excellent / 75-80 dB: Very good / 70-75 dB: Good / 65-70 dB: Acceptable to good (source by Adam, VA7OJ – grazie!)
Yaesu USA Update the FT-991′ Firmware: MAIN Ver. 02.02 – DSP Ver. 01.04 and TFT Ver. 02.01 of 24/07/2015 –
[Note]: Please read the Yaesu Firmware Upgrade Manual before proceding to the Yaesu multiple software installations and employees by different types of transfer software .exe!-
[Note] the MAIN software should be installed first! Caution: it does wipe all the settings including the memory channels. Update features: • The WIRES-X (VoIP network) function is added • Improved and optimized. (read more…)
VIRES-X: Quando viene trovato un nodo locale, il simbolo “X” è acceso stabile, e sotto nel display compare il nome del nodo (nominativo di chiamata) e il nome della città (QTH).
Leggere tutte le istruzioni con immagini incluse sul Manuale di Istruzione Yaesu FT-991 C4FM FDMA/FM (VIRES-X Edition in ENG) che si trova nella cartella .zip “Firmware_Update_JUL24″ da scaricare da Yaesu USA! – (Per i dati e le istruzioni in italiano non ho trovato ad ora linck utili! leggere, comunque altre notizie sul Manuale Utente del 991)
[Note] – Detailed specifications: please see the official sources – All specifications are subject to change without notice – All trademarks belong to their respective holders.- This page is just a non-official overview, where no one should draw any conclusions – All images and versions above is for illustration only. (tnx)