New IC718, TX-limit and TX Power

Discussion in 'General Technical Questions and Answers' started by SA7CNG, Aug 10, 2017.

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  1. SA7CNG

    SA7CNG Ham Member QRZ Page

    I just got a replacement IC718 for one i bought that was completely deaf, but this one is a bit strange aswell. It has no TX on the 40m band above 7100kHz. The TX icon dissapears when i go above 7100, and returns when i go below it again. The other bands that i checked seams to be working normally. Could i have gotten a radio for another country than my own?

    Also, i operate from a car battery that holds approx 12,4 Volts on TX and only get about 50W output power, is that normal? Im using the power cord that came with the radio.
     
  2. WA8FOZ

    WA8FOZ Premium Subscriber QRZ Page

    Yes.

    I have never used a 718 but my experience with ICs 706, 7000, and 7100 as well as other branded rigs is that they need 13.8 volts or so for full power output.
     
    W4IOA likes this.
  3. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    There isn't any Region where 40m stops at 7100 kHz, though.

    In many places it does stop at 7200 kHz. I have no idea why the rig would stop at 7100, but a call to Icom might reveal something.

    It's true that many solid state rigs cannot achieve full power unless provided with about 14Vdc, and many are "rated" that way.
     
  4. WB5YUZ

    WB5YUZ Ham Member QRZ Page

    That depends. If you are measuring output power on SSB using a simple analog meter, then yes, that could be a normal reading. Also if you are throwing a carrier on AM. But if you are sending a carrier using CW mode or RTTY mode you should see the full 100 watts out on an analog meter.

    To check, use the [SET] button to select the SIGNAL/SQUELCH/RF GAIN meter on the '718 to show power out (PO) when transmitting. It can respond faster than the needle of a wattmeter and will go full scale on voice peaks if you are getting full power out.
     
    Last edited: Aug 11, 2017
  5. SA7CNG

    SA7CNG Ham Member QRZ Page

    I tested to shorten the cable to the battery, and got 80W instead of 50W, so i guess it was only low voltage. I will half to get a powersupply of 13,8V instead of my 12,6V car battery.

    The seller replied that the IC718 is of an older model, that is restricted to 7.100kHz, but they said that they could fix it for free if i sent them the radio.
     
    Last edited: Aug 11, 2017
  6. KD4MOJ

    KD4MOJ Database Subscriber QRZ Page

    I have two 718, one purchased in the early 2000's and one a bit later. Neither one stops at 7.100

    ...DOUG
    KD4MOJ
     
  7. G8YPE

    G8YPE Ham Member QRZ Page

    Mine came out of the box about 10 years ago, with up to 7.1MHz, it was a rig made for UK sale, and that was the licence conditions at the time of manufacture, you most probably do not have 60m on the radio too. You should find an intended country of use label on the top of the box with the countries blocked in. There is a mod that will give you full coverage TX on dxmods where you take out three diodes to do it. Mine needs a min of 13.5V to give me 100W, but the radio is very sensitive to SWR in my mind and will give 70 or less if you have a badly soldered PL259 plug..
     
  8. WB5YUZ

    WB5YUZ Ham Member QRZ Page

    Mine seems to start folding back power around 1.7:1
     
  9. SA7CNG

    SA7CNG Ham Member QRZ Page

    On the box there is a sign that says what countries the radio is supposed to go to, and Sweden is one of them. I think it is a bit strange, since the 40m band has been 7.0-7.2 for a while.

    I did the TX mod my self, desoldering the D54 diode was quick and easy. I didnt need to remove the radios front, the diode could easily be reached with a soldering iron from the side of the radio once the lid was removed.
     
  10. SA7CNG

    SA7CNG Ham Member QRZ Page

    The only thing that bothers me about the radio is the fact that the built in SWR meter doesnt show any SWR value if you are under 17W output. Are your IC718's meters the same way?
     

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