Can we have a discussion about 2.4ghz?

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by KK4YWN, Jun 21, 2021.

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  1. KK4YWN

    KK4YWN Ham Member QRZ Page

    I think we can :)

    It seems to me that this band is primed and ready for an influx of hams. High-gain antennas are cheap/plentiful (mesh dishes abound). For a transceiver, the ADALM-PLUTO can easily be had for $150. SDR-console added support for receive/transmit and i have two observations about that:
    transmit audio is really good.
    receiver sensitivity seems good.

    L-com global has a 15dbi gain parabolic for $52.25.
    ADALM-PLUTO is $150.
    Add a cheap rotator for $? or possibly build.
    We need filters. Homebrew preferred, right? Can pipe-cap filters work at 2.4ghz? Is there something better?
    Needs moar powah. 20w on the cheap from sg lab. there are probably others out there.

    Thanks to the popularity of qo-100 around the world, a lot of equipment is being developed for 2.4ghz. The US and canada may not be able to use qo-100, but we could certainly help push the band into prominence in our own back yards.
    KD2RDG and N2HUN like this.
  2. KD2RDG

    KD2RDG Ham Member QRZ Page

    Isn't that the cordless phone frequency?
  3. KK4YWN

    KK4YWN Ham Member QRZ Page

    CQ cordless phone CQ cordless phone. kerosene kerosene four yachting waters nearby standing by for call
    N2HUN and KD2RDG like this.
  4. KK4YWN

    KK4YWN Ham Member QRZ Page

    All joking aside, it seems ssb on 2.4ghz is a pretty easy endeavor thanks to all the off-the-shelf components. Convincing hams to do it is the only herculean effort.
  5. W4EAE

    W4EAE XML Subscriber QRZ Page

    Anything microwave is largely location dependent. Everything I have done above the 23cm band has been transmission between stations of which I was the control operator on both ends.

    It doesn't seem that most amateurs are interested, but microwave is terribly interesting to me--mainly due to the possibility of incredible bandwidth.
    KD2RDG likes this.
  6. KA9JLM

    KA9JLM Ham Member QRZ Page

    Microwave oven and WiFi.
  7. VE3CGA

    VE3CGA XML Subscriber QRZ Page

    is this idea for satellite work? low power? spread spectrum?
    Been wondering about this myself. It would be great if we get a qo-100 type satellite for this hemisphere and make use of inexpensive tech.
    I'm skeptical or cautious of using this band....
    Its already full of wifi, ism, bluetooth, fitbits, microwave ovens, almost all RC planes, cars & drones, esp32 & RF arduino-theamed wireless devices

    just how would other users of the spectrum be protected from closeby overloading
    what kind of emitted rf power is suggested?

    I'm using several esp32's and nRF24L01 devices here, they're pretty low power but I do have them fairly physically separated
    While making a wifi garage monitor, I noticed the esp32 had to be shielded or distanced from a RCWL-0516, otherwise the sensor would get
    triggered off the esp's wifi.
    I wouldn't want to wipeout or overload my own wifi router or the neighbours, theres a 2-3 wifi's I can see 1/4mile away in an industrial park
    although possibly a solution for the pesky neighbourhood drones

    and what about the other end of things, the receiving setup noise floor from everyones wifi to outdoor wx monitors
    Even though my rtlsdr is the low end of the sdr dongles theres a ton of stuff all over its spectrum that's not AM BC images, I dont know what I'd see if I could view into 2.4Ghz

    just tryin to imagine the in's and out's of using that band, hope theres a fairly inexpensive way into a stationary hamsat setup and not go to something thats costly or more vulnerable to rain and snow as was Expressview or dishnet in our area

    found this and its has some interesting info
    KA9JLM likes this.
  8. K3EO

    K3EO Ham Member QRZ Page

    Lots of encroachment into our 13 cm and 5 cm bands from the WiFi guys. See attached chart.
    Advantages - We can use some of the existing hardware that is marketed to the WiFi guys (eg. amps, directional antennas).
    13 and 5 cm bands.jpeg
  9. W4EAE

    W4EAE XML Subscriber QRZ Page

    The 13cm and 5cm amateur bands are granted on a secondary basis. As amateurs, we must accept interference on the ISM portion of the bands.
  10. KK4YWN

    KK4YWN Ham Member QRZ Page

    bluetooth/wifi must accept interference from us. so its just like 40m's used to be except there is 150mhz of bandwidth an no woodpeckers.

    when i finish work, i'm going to do some listening on 2.3ghz with a wifi yagi and pluto. with a plain old vertical omni, the ssb call freq is dead quiet in my neck of the woods- which is quite literally the woods, as i'm surrounded by national forest.

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