Mint box transmitter/reciever

Discussion in 'General Technical Questions and Answers' started by ALEXT, Jan 11, 2018.

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  1. ALEXT

    ALEXT QRZ Member

    Hello all,
    i recently started tinkering around with mint boxes and different uses for them and i came across people who put a QRP pixie kit into a altoid tin with a battery. Ive read around a bit about them and i have a cart with a pixie kit, and i was wondering a few things.

    1. I've read some comments/posts about people saying they could talk from US to new zealand. Can a altoid tin transmitter like that actually transmit and receive from that far away? (my goal would be to make two of these transmitters and give one to my brother in germany. im in boston)
    2. i can only find DIY pixie kits online, so is there any way to buy one pre-made? if not, how hard is it to solder the kit together for a beginner? (ive done general soldering before with other hobbies)

    If i get any more questions ill be sure to add them in the comments of this post! :)

    Thanks all
     
  2. N2SUB

    N2SUB Premium Subscriber QRZ Page

    Yes, it is possible, but it really depends on your antenna. The better the antenna, the better the odds. Condx are not the greatest...do your best to predict which band is best for the times you want to operate. There may only be certain times of day when it is possible, but the East coast is open the Europe quite a bit.

    I don't know of anywhere to buy the kit pre-made. They are cheap, so if you're not sure if you're up to it, buy several and you'll have extra parts. Make sure you have a good, temperature controlled soldering iron with a pencil tip, and use top-quality solder. It will be a good experience. :)
     
    ALEXT likes this.
  3. ALEXT

    ALEXT QRZ Member

    Could you recommend a decent antenna for something like the pixie kit?
    i know the kit has a lead for an antenna, but what sort of input thing would i solder onto the lead?(to plug the antenna into)(a.k.a. what goes between the antenna and the lead?)

    can you explain what you were talking about when you said:
    "do your best to predict which band is best for the times you want to operate. There may only be certain times of day when it is possible, but the East coast is open the Europe quite a bit.
    "
    sorry for having so many question :p do tell me if they get annoying

    im looking to replicate something like in this article: https://everydayready.wordpress.com/2017/03/20/pixie-2-enhanced-kit-what-you-need-to-know/
     
    Last edited: Jan 11, 2018
  4. N2SUB

    N2SUB Premium Subscriber QRZ Page

    Well, first off, I did find an assembled version of the Pixie:
    https://www.newegg.com/Product/Prod...Kqasq-5zITeTJEsBxHYaAuKbEALw_wcB&gclsrc=aw.ds

    Based on the pictures in your link, it looks like a few modifications were made to the original kit:
    • The power jack was replaced with a standard 9V cap and battery
    • An on/off switch was added
    • The 50ohm antenna jack was hard-wired to a RCA jack for the 'Hot" side of the antenna. The ground is coupled in to the antenna itself
    • A piezo buzzer was added between the key and phone jacks. I cannot see the connections so I don't know how it's used
    As far as an antenna is concerned, what he has will work. You would probably get better results using a 50 ohm connection to a simple dipole or even QRP vertical. It may not be possible to fit a BNC or SO239 jack into the enclosure. It seems like a nice little project.

    upload_2018-1-11_11-49-44.png



    [​IMG]
     
  5. ALEXT

    ALEXT QRZ Member

    just as a recap and some clarifications overall:

    power: how hard is it to switch the power jack with just two soldered wires for power?
    antenna: i should keep on the white jack and plug a 'simple dipole' antenna?
    range: your proposed antenna setup would reach how far? would it reach germany?
    random thought: could i attach an antenna cable to a drone and fly it up high? xD

    also could you recommend a key thats not too expensive? then i would just need to learn morse code xD

    thank you for all the help again, i know how much patience it takes to explain things 12 times to a newb :)
     
    Last edited: Jan 11, 2018
  6. VK3YE

    VK3YE Ham Member QRZ Page

    Potentially yes but in actuality the chance is very low.

    If you wanted to maximise the chances you'd convert it to WSPR. You wouldn't have a two way conversation but there would be a real possibility of it being heard in places like NZ for the following reasons:

    * It could be on 24 hours/day (so that when conditions are great you're not missing them)
    * The lack of frequency agility isn't an issue
    * You're transmitting to equipment with better receivers
    * The slow transmission rate of WSPR is more efficient than CW

    But getting back to CW the chances are very small due to:

    * Low transmit power
    * You may be using it with a non-optimised antenna with poor low angle radiation
    * There are relatively few ZLs on the air and the chance that one is on when you are AND conditions are absolutely optimum is small
    * The crystal controlled nature of very simple transmitters means you are unlikely to be on the clearest frequency on the band. And you need to be since you'll be the weakest signal on the band on the other side of the world.
    * Contacts are more easily made through 'search and pounce' where you need to be frequency agile rather than crystal controlled (where you're relying on someone to answer your CQ)
    * Receivers simple homebrew equipment aren't good enough to hear long-haul DX due to poor selectivity or front-end performance

    It is essential that DX-worthy QRP gear meet the minimum standards for homebrew gear at http://home.alphalink.com.au/~parkerp/qrp/equipment.htm
    And even then DX contacts will be the exception rather than the rule unless your antennas are first-rate.
     
  7. ALEXT

    ALEXT QRZ Member

    thank you for the answer. what would be a good antenna for small distance communication?
     
  8. VK3YE

    VK3YE Ham Member QRZ Page

    Bit like asking how long is a piece of string.

    Need to know factors like distance, frequency, time of day, available space etc.

    Ideas at http://home.alphalink.com.au/~parkerp/projant.htm
     
  9. ALEXT

    ALEXT QRZ Member

    so this is what specs the pixie transmitter/reciever has:

    ower supply: DC 9V-14V

    Antenna: 50 ohm, unbalanced

    Receive quiescent current: 10mA @ 9V

    Transmit power: 0.8W @ 9V, 1.2W @ 12V

    Frequency range: launch 7.023MHz, receive 7.023-7.026MHz (7.023MHz crystal)

    Mode: CW

    time of day would be 5-9pmEST ish and my house is surrounded my trees so i dont know if that'll block signal to an antenna. i would like a not so expensive antenna if possible.
     
  10. ALEXT

    ALEXT QRZ Member

    also to follow up on my above^ question: i've seen some people with a 'tuner'. Do i need a tuner with this altoid setup? qrp-pixie-5.jpg
     

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