• [OZ9QV] Quick Test of Some Receivers for Monitoring.

    From OZ9QV via rec.radio.amateur.moderat@21:1/5 to All on Tue Jul 5 15:58:54 2022
    XPost: rec.radio.amateur.moderated, rec.radio.amateur.equipment

    OZ9QV : Amateur Radio, Propagation and Electronics

    Quick Test of Some Receivers for Monitoring.

    Posted: 04 Jul 2022 02:56 PM PDT http://oz9qv.blogspot.com/2022/07/quick-test-of-some-receivers-for.html

    Over the week end I found some older scanner receivers etc that I want to
    use for propagation monitoring and general (local) traffic monitoring.
    Because I like to have the monitoring running for hours every day, and
    using solar power, I want to limit the power consumption.
    Monitoring FM channels:
    I have a 10m FM transceiver that I intend to use for monitoring 10m FM on 29.600. Draws 160mA on receive, which is acceptable, though not ideal.
    Current consumption is still about 160mA, but it is better than using the IC-703. For 10m FM it is also possible to use a Bearcat UBC92XLT handheld scanner running 6V with 70mA current consumption. A voltage regulator
    reducing the 13V to 6V will be necessary for this (easily built).
    For 6m FM, monitoring frequencies in the 51-52MHz segment I can use my
    older Yaesu VX-5.
    The best results of those came with 2 handheld scanner receivers, Bearcat UBC65XLT. These are 10 channel units capable of running in the 4m, 2m and
    70cm bands. They draw 5mA when off, and 50mA when receiving.
    I think that one of those should scan the 4m FM segment - 70.300 - 70-500 -
    9 channels, and 69.900. the frequency pair 69.900/70.500 is allowed in
    Denmark for use with repeaters - yes 600kHz spacing, just like the 2m repeaters.
    The alternative would be using a (Wouxun?) handheld for this purpose, if I
    can find out how to program its memories.
    The second one can be used for 2m, and the 143.625 MHz, all in 25kHz
    spacing system. 143.625 has been used by the space stations Mir and ISS for communication with the ground stations in Russia.
    For 2m FM I could also use my older Kenwood handheld TRX, or a Baofeng as monitor, again if I can figure out how to program the beast. Since I have
    no intention of transmitting with those I have no problem using those
    Chinese radios for monitoring.
    For 70cm I could use the Baofeng's again.
    Now, what to do for 23cm? I do have an old Kenwood TM741 triband radio, and that could be useful for FM monitoring on that band. I will have to test
    the power consumption of this one, but it does have the advantage of being capable of running 3 bands simultaneously, with additional transmit
    capability. I can likely find a low power scanner capable of running 23cm.
    We shall see.
    I am well aware that some antennas will be necessary for all this (and
    more) monitoring.
    The advantage of receive-only antennas is that the preamplifier, if it is necessary, can be placed close to the antenna, so a low cost coax cable
    (cheap satellite cable) can be used.
    The 10 - 6 - 4m, and 8m bands could be covered by a TFD antenna about 2.5m long, hanging in a tree in the garden. Essentially invisible.
    For 2m, 70cm and 23cm a short tri-band vertical can be used, with a
    wideband preamp, and stilll the low cost cable. Not invisible, but
    relatively discreet. Yes I am aware of the possible overload of some
    receivers when transmitting, but that is, for now, an acceptable compromise. For reception on bands in between - such as air band and FM broadcast radio
    of both Western European and Russian stations, a wide band antenna, such as
    a discone or a log-periodic antenna could be used with a wideband
    The next level will be some monitoring using FT8 and beacon reception, and
    this requires more sophisticated reception systems capable of SSB. I have
    some ideas, but this will have to wait for another time.

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