My "Opportunity to Learn"......... ;-)

Discussion in 'Working Different Modes' started by KA5LQJ, May 2, 2012.

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  1. KA5LQJ

    KA5LQJ Ham Member QRZ Page

    Hi All!

    I'm wanting to take my Icom 706 MkII-G and go 'digital' as well as regular 'voice'.

    First of all, besides CW, which digital mode is the most stable during a severe lightning and thunderstorm. At present, I don't have any towers to lay flat, but I want to use it on HF, 6 meters, 2 meters and 70 cm. I do know that lightning is a sudden static burst, How does
    this effect the digital signal?

    Now, also, I'd like to know what equipment I'd have to have to run CW and digital
    mode? The mic connector is a J-11, an 8-pin telephone jack. I'm trying to use the
    KISS configuration, small parts and small cost.

    I'm a Skywarn "old fart" who is looking to help a lot of places who want to "share"
    storm information and the path of the severe wx. I need to know which digital mode
    is NOT affected by lightning. The antennas will be horizontal in polarization, except
    the 2 meter FM, that's for hitting repeaters via "voice".


    Don/KA5LQJ/2AU368 -Alpha United DX club
    Last edited: May 2, 2012
  2. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Anything that's frequency modulated and not amplitude modulated is more immune to static and noise bursts. Much as I love CW, it doesn't fall into that category. Not a bad synopsis here:

    Such bursts don't affect the signal at all, but do effect reception of the signal. The problem is in the detection or demodulation, not in the signal origination. Again, anything using phase detection is more immune than anything using amplitude detection.

    It would be a bad idea to use that connector for anything other than the microphone. For CW, you use the rear-panel KEY jack. For digital modes, you use the rear-panel DATA (6-pin mini-DIN) jack, possibly along with the 2-pin REMOTE jack. The IC-706MK2G manual explains all this quite clearly and shows how to make all the connections.

    The problem with modes other than voice is unless people on the other end are equipped to deal with them, and ready to operate those modes, you'll be in contact with "nobody." For example, PACTOR is great and pretty noise immune, but if you're the only one using it, it's worthless. Best to have a "network" all set up where everyone agrees what mode they'll be using in an emergency, are set up, checked out, and good to go.
  3. K0RGR

    K0RGR Premium Subscriber QRZ Page

    I would suggest a RigBlaster PLug n' Play. They make an adapter that plugs directly into the zillion pin accessory plug on the back of the 706, so you don't need to mess with the microphone connector at all. It's a pretty neat installation, just one USB cable and the two audio lines to the computer. You can buy other adapters to use it with several different radios. Here's a web page with the details on the adapter required: You can also do CI-V control from this same adapter. The only things I never had luck doing was using the CI-V and doing CW at the same time - a separate CW interface like the WinKeyer would be a good investment.

    I run a net using Olivia 16/500, and it works well under utterly horrible conditions. I can copy signals I can't hear or even see on the waterfall display. The mode has so much redundancy and forward error correction that it is fairly immune to most bursty static. It is, however, very slow. There are MANY Olivia nets springing up around the country. Google 'NBEMS' and you should find lists of them. Some of these nets use other versions of Olivia and other modes.

    PSK31 is the most common conversational mode. JT-65HF is used for making brief contacts under extreme conditions. I used to run 2-3 watts to a piece of wire hung in a tree outside my window on JT-65HF and I had QSO's with people all over North America and Europe on 20 meters and higher. WSPR is another interesting very low power mode.

    One very important hint: turn the AGC off when doing digi modes, and use the RF gain to adjust the sensitivity. This is really helpful when the band is crowded, and there is a mix of weak and strong signals. With the AGC on, the strongest signal will wipe out the weaker ones.
  4. N9DSJ

    N9DSJ Ham Member QRZ Page

    A complex question, actually. Modes with very heavy FEC/redundancy (JT65x, WSPR and such) tend to work the best for high static burst environments at the price of throughput. Steve is correct on AM versus FM modulation schemes but a S9 +60 dB noise pulse pretty much kills everything within its lifetime. A lot depends on the propagation mode and frequency you wish to operate. A burst optimized mode like JT6M or FSK441 would work also ok where it is legal as it is only "looking" for a very short time slice of a decodable signal. Note that none of the modes I mentioned are "conversational", so a great deal depends on your communication intentions and the resultant trade offs.

    Bill N9DSJ
  5. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I sure agree. And as I posted earlier, it doesn't matter what you use; if others in the same network aren't using the same thing, zero contacts will result. For storm spotting and such, this takes a coordinated effort.
  6. G0GQK

    G0GQK Ham Member QRZ Page

    Well I'll tell you something for nothing, if I were you I wouldn't be operating anything if you can hear lightning in your area.! Switch off, unplug the rig and everything else because if you have an icom the quickest way to get it not working is to have some surprise lighting coming down the antenna !
  7. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Real men operate right through lightning storms.

    Here's a (pretty bad, but it's old) picture of our operating setup for the June VHF QSO Party at Chincoteague Island, VA in 1988. We had a lightning storm literally right on top of us, with thunder so loud it was deafening; lightning so bright it was blinding; and lightning crash noise levels of S9+60 dB (but they subsided in between strikes and we could hear stations okay).

    We had 20 elements at 75 feet on six meters; 76 elements at 100 feet on two meters; and 556 elements total on 222-432-902-1296 MHz at 55 feet (although that tower is almost nested in this photo, I think we had high wind gusts along with the lightning). All fully connected right through the storm, and we never went off the air even for a minute. Too much fun and the bands were good.

    We're all still here.

    Although I now have a lightning bolt mark on my forehead, kind of like Harry Potter...

    Attached Files:

  8. VA7CPC

    VA7CPC Ham Member QRZ Page


    I have lots of respect for WB2WIK, but we disagree on this one. If there's lightning in the vicinity, disconnect your antennas and quit operating until it's gone.


    PS -- it's probably possible to create a "lightning-safe" antenna system and shack, using enough grounding, Faraday-cage structures, and lightning-protection gear. But most of us don't have that kind of expertise.
  9. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    In the field operation described above, we were careful to not ground anything except by accident and we operated from tents made of nylon or something. So we had everything covered!
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