Aprs onanalog fm HTs?

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by KF5DMC, May 16, 2018.

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  1. KF5DMC

    KF5DMC Ham Member QRZ Page

    Will aprs work with analog FMHT's
    I ask because I have a T70A dual bander icom Ht...
    Im only lookin to find out if I can use my HT for aprs..
    I do have aprs gps software for andriod currently and can get it and use it with my apple ipad...
    Any help appriciated
  2. WE4B

    WE4B Ham Member QRZ Page

    Yes. 144.39 MHz.
  3. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    Yes. You will need to buy or build an interface between the computer soundcard and the HT audio In/out and the PTT.
  4. AD7ZJ

    AD7ZJ Ham Member QRZ Page

  5. AG6QR

    AG6QR Premium Subscriber QRZ Page

    Aprsdroid can do AFSK directly, with no need for a TNC. If you have a radio that supports VOX, all you need is an audio cable to connect the audio output of your Android device to the microphone input of your radio. If you want to receive APRS as well, then you'll also need to connect your radio's audio output to the Android device's microphone input.

    I prefer using the mobilinkd TNC, as pointed out by AD7ZJ. It communicates with your Android via bluetooth, so the Android device doesn't need any cables to it at all. And it can provide a keying signal to your HT, not relying upon VOX. I've had a moblinkd TNC for a few years, and it has worked well.

    All the digital signals go out on analog airwaves, so it's no surprise that an analog HT works well for APRS.
    AG5DB, G0CIQ and N1ZZZ like this.
  6. WZ7U

    WZ7U Ham Member QRZ Page

    And no special "digital" antenna required!
    UT7UX likes this.
  7. HA2ZB

    HA2ZB XML Subscriber QRZ Page

    This is the thread closest to my issue. I connected my HT (Wouxun KG-UV9D) to my Android phone (Samsung Galaxy A8) with homebrew cable(s). I am using APRSDroid app.

    TX is working, but I have an issue with packet reception / decoding. I connected headphones through a Y-cable to monitor the incoming signal. Packets that seem clear and strong were not detected, than I played with HT volume - moderate success, but still not 100%. Only 70% or less. Tried opening the squelch... no big change.

    So any experiences, tips, advice would be appreciated, especially:
    • How do you manage (disable, change) Android automatic level control and popping up volume setting panels? (No rooting...)
    • How do you monitor the incoming signal?
    • What are the optimal AFSK settings on APRSDroid?
    • Are there any viable alternatives to APRSDroid?
    Thank you in advance!
  8. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    -Squelch should be open for weak signal work when using FM radios.

    -Volume: Volume should not be too high nor too low. Too high a volume can overdrive and cause distortion.

    -Audio Path: When working with multiple devices in an audio chain one should seek to have roughly the same amount of gain/volume through each device to prevent distortion. I often start with roughly 40% as a setting across the chain. Make adjustments roughly equal on each device. An oscilloscope can be helpful for measuring audio level and modulation if one takes a more technical approach.

    -Digital Signal Levels: Generally one should disable or turn off any processing of digital signals because they can distort the signal, e.g. AGC, DSP, NB. Give the software the unmodified signal from the air. Note: NB is intended for repetitive noise, specifically Automotive Ignition. Many hams seem to misunderstand or use inappropriately. Having NB ON, with very strong signals present can cause audio distortion.
  9. K8XG

    K8XG XML Subscriber QRZ Page

  10. HA2ZB

    HA2ZB XML Subscriber QRZ Page

    I do not use TNC, HT is directly connected to audio connector of the phone and APRSDroid codes/decodes.

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