Got a transceiver... how do I know if it works?

Discussion in 'QRP Corner' started by N5HXR, Oct 23, 2019.

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  1. N5HXR

    N5HXR Ham Member QRZ Page

    OK, I built my transceiver (20m QCX from QRP Labs, build notes here). It seems to work -- I can listen to people, copy CW when it's slow enough, etc. I was even able to see my (very faint) signal on one of the WebSDRs (in Virginia, and I'm in Baton Rouge, LA, so that's pretty cool!).

    I tried sending CQ some, but I know I'm a really faint signal. I'm probably getting something like 2W out of the antenna (after feed line and matching loses), but it's what I've got until I can save up for something better (going from 12V to 16V might help...).

    I thought another good test would be to see if I can show up on RBN. Despite trying a bunch of times on different frequencies, and with the automated beacon feature on the QCX so I know it's not my bad straight key timing, I don't get anything. I've tried sending "TEST KI5FXG", and "CQ TEST KI5FXG", which I think should work according to the docs. Is that right, or should I be doing something else there?

    And given that I'm a weak signal, how do I know when is the best time of day, best frequency, etc. to maximize my chances? Is there some special juju I should know for the 20m band?

    WW2PT likes this.
  2. WW2PT

    WW2PT Ham Member QRZ Page

    You can monitor your signal remotely on one or more of the WebSDR online receivers. Find a clear frequency, send a bunch of VVV’s and see if you can hear yourself on the east or west coast, EU, SAm, VK/ZL land, etc.

    Good luck! Follow up with your results. I have a 30m QCX on my bench waiting to be built.
  3. KF9VV

    KF9VV Premium Subscriber QRZ Page

    Send a CQ. If you are getting out, you will be spotted.

    Also, check out VOACAP for propagation predictions.
  4. KM4DYX

    KM4DYX Ham Member QRZ Page


    20 has been pretty good as of late. What is your antenna system?
  5. N5HXR

    N5HXR Ham Member QRZ Page

    I have a 20m dipole in the attic, though the feed line is a 50' RG58 cable. SWR at 14.040 is about 1.18:1. I have a choke balun at the feed point.

    Since I'm running the QCX at 12v and have that long, lossy feed line, I figure I can't be getting more than 1.8-2.0 watts out.

    It's oriented so its broadsides point NNE/SSW. With my SDRs, I catch a lot from the US eastern seaboard and into Europe.
  6. N7EKU

    N7EKU Ham Member QRZ Page


    Check out Set your power, antenna, location, mode and time of day and see what your chances are.


  7. N8TGQ

    N8TGQ Ham Member QRZ Page

    Coordinate with a ham from your local area for a test run. This is another reason to be a member of your local radio club. You'll get all the advice and help you need!
  8. KC7JNJ

    KC7JNJ Ham Member QRZ Page

    If you have another receiver you could use that to see what you sound like. I have always kept a shortwave with a bfo.
  9. KM4DYX

    KM4DYX Ham Member QRZ Page

    I wouldn't sweat the feed line loss at 14 MHZ. Chances are that your system is no barn burner in the gain department, though. Our antennas point at one another. If you ever want me to listen for your test call let me know via PM or email.

  10. N5HXR

    N5HXR Ham Member QRZ Page

    Hah, more things to buy! I can only buy things so fast, unfortunately. I can see stuff show up on my SDRs, and today I saw a somewhat-brighter line on two WebSDRs (one in Virginia and one in Pennsylvania) when I called CQ. So I believe I'm radiating...

    Someday I will buy a commercial rig, but that's more like end-of-year bonus time :).
    WW2PT likes this.

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