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. KA9JLM

    KA9JLM Ham Member QRZ Page

    lol. Now that is funny.
     
    K0UO likes this.
  2. W6RZ

    W6RZ Premium Subscriber QRZ Page

    Not entirely. Amateur radio is primary at 2395 to 2417 MHz and co-primary with mobile at 2390 to 2395 MHz. At 2300 to 2305 MHz, we're secondary, but there is no primary user.
     
    K3RW likes this.
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    With a vertical or omni I'd never hear any amateur activity on 2304 MHz SSB/CW/etc.

    However, with a good horizontally polarized and rotatable antenna up high enough in the clear to not be blocked by any local obstructions (unfortunately "obstructions" at 2.3 GHz includes trees), several times each year there's a LOT of activity: January VHF Sweepstakes; June VHF QSO Party; August UHF contest; September VHF QSO Party. In October, November and December are EME contests which promote 2.3 GHz activity, but not terrestrially.

    Fun fact is when there's a good tropo duct, it works fine at 2.3 GHz (and usually also at 3.4, 5.7, 10.3 GHz etc.) and may not work well at all on 222 or 144 MHz, and often "not at all, period" at 50 MHz. The UHF-SHF bands are where they shine, and when one occurs that promotes more action quickly. But signals aren't "strong," so FM use or even weak signal modes using an omni may be very disappointing while weak signal modes with high-gain directional antennas can work wonders within the duct.
     
    NE3R likes this.
  4. K6CLS

    K6CLS Ham Member QRZ Page

    You are fortunate to have a very active and knowledgeable bunch of folks in the area, and terrain that supports good activity.
     
  5. K3EO

    K3EO Ham Member QRZ Page

    Years ago, QST published an article about a 2.3 GHz repeater that was active in California. I think the users used transverters, but my I don't remember the details. I believe the article was written in the 1980's or 90's.

    By the way here is a RigPix link to a 13 cm FM transceiver (TM2400) that was only available in Japan during the 1990's.
    https://www.rigpix.com/kenwood/tm2400.htm
    I sure would love to have a couple of these to play with.
     
  6. KK4YWN

    KK4YWN Ham Member QRZ Page

    The adalm-pluto sdr learning device can cover 70mhz-6ghz all-mode in full-duplex glory. 2.4ghz output is quite low at 1-2 mW, but we're starting to see preamps etc come to the marketplace. using sdr console, you can do 5khz wide ssb with built-in eq and compression. it sounds really nice. at $150 its hard to beat. the ADC is 12-bits wide so the receiver is actually pretty darned good for the price. if you add a network adapter you can remote-mount the radio and access it via ethernet, allowing very short coaxial runs and low loss.

    check out the langstone project for some idea for a homebrew transceiver using off-the-shelf goodies
     
    K3EO and KY4GD like this.
  7. KA9JLM

    KA9JLM Ham Member QRZ Page

    You can make a transmitter using a microwave oven.
     
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    And with each contact, you can say, "Now we're cookin'!"
     
    KY1K and KA9JLM like this.
  9. KK4YWN

    KK4YWN Ham Member QRZ Page

    unless you've configured the transmitter to defrost.
     
  10. K3EO

    K3EO Ham Member QRZ Page

    Thanks for the info. The langstone project with external amps is a lot less expensive alternative than a pair of Kenwood TM2400 for 2.4GHz.
     

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