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Thread: Frustrated IC-718

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  1. #1
    Join Date
    Dec 2004
    Location
    Farmingville, NY
    Posts
    19

    Default Frustrated IC-718

    Thanks in advance for reading and especially thanks for any constructive help. I am new to HF and here is my issue:

    Bought a IC-718 on Ebay - appears to be in excellent condition
    Put up a Buxcomm Windom Dipole antenna about 50-55ft in a tree. One leg is going to my chimey via a tie down rope (15ft off the ground), Other leg is tied into a a tree (15ft off the ground). Feed line is Coax 213 at 200ft. It runs down the tree, along the ground to the fence and goes into my attic and down into my shack. I have about 15-20 feet of extra line in the attic. I run the antenna into the IT-100 LDG tuner and have a matching 50ohm line (3ft) going to the IC-718.

    The good: I hear everything nice and clear with just what I can consider standard background noise. I hear conversations on 20M and 40M just fine. The IC-718 SWR meter shows 1:1 to 1:3 SWR on all bands. My mic gain is set to 50, COM is on and everything seems ok with my very limited experience on HF (virtually none).

    The bad: I can't make any contacts. I have barely made part of a contact with two guys already having a conversation that I was hearing nicely and just asked if I could join, they complained that my audio was going in and out. I have also made another contact that says after my call sign my signal would go out. Output power shows that I am going out at nearly 100%.

    At first I was thinking that my feed line was causing a drop in power, and I don't have any equipment to test my antenna or a dummy load to test output. I fear that my power is dropping so low that I cant get out. It could also be the radio, or the microphone. Not sure what to replace first or buy to test because funds are limited.

    Anyone have any suggestions? Anyone live on Long Island that will be willing to act as an elmer and show me the ropes and help me test my setup? I am completely frustrated and losing hope.

    Thanks

    Bernard
    KC2NKL
    Selden NY
    bernardhny AT gmail dot com (email me and I will give you my number and maybe we can talk on the phone instead of trading forum posts?

  2. #2

    Default

    Check your power supply. Put a VOHM meter on it - key up, talk, say something - see what the voltage is.

    Many, modern solid state rigs are fairly intolerant of low voltages - want to keep it near 13.8 when transmitting.

  3. #3
    Join Date
    Dec 2004
    Location
    Farmingville, NY
    Posts
    19

    Default

    The power supply I am using is an Alinco DM-30MV that shows that I am steady at 13.8 while transmitting. I made a contact tonight with a guy in Indiana who said my audio was great but my signal was coming in weak. I think that might rule out the mic being the problem but I don't have the experience to judge. I was hearing him and another guy clear as day like they were sitting in the same room. I really wonder what the output power is to the antenna. I wonder if my 100W signal is getting to the dipole at something less substantial. It was nice to make a contact, but I was hoping that I wouldn't be having the problem my signal.

    Thanks

    Bernard
    KC2NKL

  4. #4
    Join Date
    Oct 2006
    Location
    in a seaside village
    Posts
    2,066

    Default

    Now that you have the antenna up, its difficult to check the continuity of the coax. Even slight imperfections in long coax runs can greatly affect transmission and reception. However, you should check the part of the run that enters through the house for physical defects (kinks, splits in the casing, etc.)

    Although this might not solve your problem directly, you might want to shorten the length of your coax run. 200' is a very long run even with low loss coax. Your level of signal attenuation might be quite high even if the impedance matching (SWR) at your rig is sufficiently low. It pays to have the shortest length of feedline possible. If you don't know how to solder or crimp PL-259's, see if a more experienced ham can visit you and show you how.

    If you don't have a multimeter, now would be a good time to get one. As KA7O said, it's useful for figuring out possible power supply issues. A multimeter is also necessary to check for faults in feedlines. Multimeters are also useful for electronics projects --- 1001 uses really. You'll find one real cheap at the next hamfest, no doubt.
    73, Jordan

  5. #5
    Join Date
    Feb 2004
    Location
    Bakersfield, CA
    Posts
    4,775

    Default

    What you could try is to make another antenna. It's easy and requires just some wire. Make one for 20 meters. If you don't have a 1:1 balun for it, that's okay. Just hook the antenna up to your rig and start adjusting the length (put the auto tuner in bypass) until you have a low SWR as indicated on the IC-718. The antenna can be suspended from the roof of your house and in an inverted vee style have the ends going down to the ground. The ends can be very close to the ground but not touching it. About 1 to 2 ft will be okay. The coax can just be connected directly to the wires that make up the antenna. The wires you would need are two sections of wire that are 16' 5" each (468/Mhz=Feet). one goes one direction the other goes the opposite direction. At the top of the antenna hook one wire to a center conductor of the coax and connect the shield of the coax to the other wire. Run the coax into your station and check the continuity of the antenna. With it disconnected and no balun you should have an extermely high resistance, like an open. If it checks out okay then connect the antenna to the IC-718. Turn the band select for 20 meters (14Mhz) and give a listen. During the day you should be getting some signals. Now check the SWR of the new antenna at the bottom of the band, write it down, then check the SWR at the top of the band. If the SWR is lower on the bottom of the band your antenna is too long. Go outside and on each end of the antenna clip 2" off. Now check your SWR as before and see if it is getting lower. Continue to trim the antenna until you have it tuned to the portion of the band you want to operate. With it finalized you are now ready to try it out. Give someone a call. See if this new antenna works any better than your OCFD. If it does then your OCFD is doing something strange. If it doesn't then you may have a rig problem.
    You should get a dummy load soon. A wattmeter is a nice addition. The only ways you can see your power out on SSB you need either a peak reading wattmeter or you can whistle into the microphone and on a regular wattmeter it will show your power out.
    BTW, the new 20 meter antenna is just up so you can test your total installation. After you're done with it just take it down and store it for latter use.
    Hope this helps
    73
    Gary

  6. #6
    Join Date
    Dec 2008
    Location
    Cupertino, CA
    Posts
    835

    Default

    Lots of variables here.

    There are going to be ground losses (power absorption) with the dipole that low to the ground - especially on the lower freq bands. You might hear 40m well enough; doesn't mean the antenna is going to be that efficient at that height when transmitting. Ideally, you would want to put the antenna up at least 1/2 of a wavelength high of the band you want to operate on. eg: 40m/2 = 20m high. Or higher; but we are talking about optimizing here. Ya might consider getting the dipole up to 35 or 40 ft if you can.

    The distance of the ends of the dipole to nearby objects can also affect its state of tune. Give it as much space as you can.

    Another variable is the direction of the wires. Remember, that a dipole is going to transmit off of each side of the length of that wire. A dipole that has its wires going N to S is going to talk best from E to W. And vice versa.

    Half of the fun of ham radio is monkeying around with your gear. You will do that when it comes to working on antennas and getting them optimized. Just scratching the surface here with some thoughts . . .
    Last edited by KI6USW; 04-08-2012 at 05:03 AM.
    [COLOR=#000000][FONT=verdana]“Politics is the art of looking for trouble, finding it everywhere, diagnosing it incorrectly and applying the wrong remedies.” Groucho Marx[/FONT][/COLOR]

  7. #7
    Join Date
    Jan 2008
    Location
    St. Mary's County Md since 2000
    Posts
    7,939

    Default

    I recommend turn Compression - OFF.

    Let's eliminate variables, besides it may help punch through in rough conditions but it does not make listening kind on the other end.

    Two contacts is not a very good sampling. As mentioned, conditions vary all the time. I would keep working at making more contacts and see how things develop. At first blush a weak power supply or something overheating seems most likely. Though your power supply seems good. Check your connections for cleanliness and tightness.

    good luck, bill
    QRZed: "Professional Grade Paranoia From Amateurs"

  8. #8
    Join Date
    Dec 2008
    Location
    Cupertino, CA
    Posts
    835

    Default

    Just remembered something about the IC-718. I used to have one. It has a protection circuit on the output that may be faulty. It is there and designed to turn the power output of the radio automatically if it sees a a bad SWR. This circuit protects the final output transistors in the radio by cutting back the power output.

    There are two reasons this may be happening:

    1) That protection circuit may be faulty and begin to kick in too soon if it sees a SWR over 1.5 to 1. That was the case with the 718 I had. It should still be under warranty if it is new, so you can take it in to the dealer and have a tech check it out. It is a simple fix; but I cannot recall exactly what the actual cause was ATM. You can even Google that info, as it is a known fault/defect with it. Doesn't make it a bad radio for that reason. Not all of them did that.

    2) Or - your SWR is climbing higher because the antenna isn't as well 'tuned' as you think it is when talking. Then, that protection circuit will kick in because that is what is was designed to do. It should protect the radio from any SWR greater than 2:1. That would be my FIRST guess - really.

    Even though the radio is designed to run @ a full ~100 watt output, I wouldn't do that until you are CERTAIN that the antenna is resonant and your match is stable. Even then, I never run my radio past 80 watts even when contesting. Get your antenna right so that it does the work as it should. Don't accept the thought that the only answer to this dilemma is adding 1,500 watts. If you get the antenna optimized, you'd be surprised just how far you can talk with less than 100 watts. The comment that said you have too much coax coiled up doing nothing is true. Use that extra length to get that antenna as high as physically possible w/o endangering yourself. Get help if you must.

    End of rant . . .
    Last edited by KI6USW; 04-08-2012 at 07:19 AM.
    [COLOR=#000000][FONT=verdana]“Politics is the art of looking for trouble, finding it everywhere, diagnosing it incorrectly and applying the wrong remedies.” Groucho Marx[/FONT][/COLOR]

  9. #9

    Default

    Quote Originally Posted by KC2NKL View Post
    ...they complained that my audio was going in and out. I have also made another contact that says after my call sign my signal would go out. Output power shows that I am going out at nearly 100%. ...?
    Don't overlook the possibility of a bad mic connection that could be intermittant.

    SSB mode, that can easily cause what you are reporting.


    73

  10. #10

    Default

    Could be many things including operator inexperience.

    Since it's a used rig, it could easily have problems. I'd recommend finding a local with HF capabilities (L.I. is loaded with hams and ham radio clubs) and bringing the IC-718 to his shack and trying it there to see what's going on.

    If you're not a member of a local radio club, now's a good time to join one.
    What if soy milk is just regular milk introducing itself in Spanish?

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