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

  • 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

  • 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..

    Peter Gülzow | DB2OS | AMSAT-DL member since 1983 | JO42VG

  • I believe the FT-100 is very deaf outside normal amateur radio frequencies. So yes it tunes but really may not be suitable.

    Dave Cawley | Ex G8EAO & G6ANG/T |
    (when you had to have a separate TV license !)

  • How about using a SATfinder,but is 950-2150 rx. Any tried this?


    73's Jerry

    Jerry the question here was about NB transponder....


    Your question belongs to WB transponder, hi hi....

    (but in fact a sat finder with built in screen and RX works well for receiving WB beacon)


    73 de Oscar DJ0MY

  • 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.


    Peter : 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 ;).