Anybody tried receiving 739MHz with wideband RX of FT-100, IC706, FT-897, ... directly?

1st Official Post

    I'm currently using a FT-100 as transmitter. This TRX has a wideband receiver. So I tried to receive the 739 MHz directly.

    It worked, but this RX is not sensitive at all on this frequency. Even using an additional SAT-inline amplifier did not move the s-meter a bit when receiving the PSK beacon. But SSB, CW signals were readable.


    Let us share more information about RX capabilities of transceivers here.


    73 Mike

    DL1GNM That's peculiar because most LNB's have huge gains (due to the use of crappy coax intended for it's primary use: the reception of TV broadcast, not a CW- or PSK-beacon ; -) in the (claimed) order of 50 - 60 dB. This amount of gain almost HAS to compensate losses in the receiver?


    I own a FT-857 (technically identical with a FT-897) but mine doesn't go to 739 MHz (stops at around 480 MHz, if I remember correctly <-- will check this later)

    Unfortunately, all my VHF/UHF capable ham TRX are unable to RX on 739 directly - except my hendheld Kenwood TH-F7E....


    But on that frequency range it only accepts FM-W modulation (since it thinks its a TV broadcast band).....SSB is only selectable on lower frequencies within parts of the specified RX ranges.


    What works very well however is my Yupiteru MVT-9000 portable hand scanner (equals Stabo XR2000)....I guess the well known AOR scanners should do a good job as well as most of the higher end models offer SSB demodulation.


    73

    • Official Post

    DL1GNM Something must be broken.. use of an SAT-Inline amplifier is nonsense for QO-100, unless you have 100m of cable or so.. ;) What kind of BIAS feed do you use? Maybe a broken RF connector? You should see a huge increase of noise just from the LNB even if it's not pointing to the satellite..

    In Doha we used for some tests an AOR AR-6600 wideband receiver (100kHz to 3 GHz) and it worked great with high readings on the S-Meter just from the noise, so we had to crank down it's gain..

    I was wondering if the NB beacon could be received with a satfinder to make some alignments, modifying the satfinder?


    73's Jerry

    My dish, LNB and the rest of my RX is working very well. A71A DATV beacon is about MER > 8.5dB. Just want to know about the RX capabilities of commercial TRX.


    Indeed, the FT-100 is very deaf. As soon I have some spare time I'll try to measure the level that's needed to move the s-meter.


    DL1AVX: noise increased-but still not enough to move the s-meter.


    Regards, Mike


    PS: IC706 should be able to receive 739 MHz.

    Here we go:


    FT-100 RX USB, in dBm; MDS is subjective

    2019-07-20, DL1GNM


    Freq/MHz MDS S1 S5 S9

    739.200 -90 -53 -50 -35

    432.200 -137 -111.6 -109 -94

    144.200 -136 -110 -105 -86


    Just measured, using my old R&S XPC lab transmitter, and not very scientific. It seems that somewhere in this RX ~50dB were lost ;).