Icom 7300 Paired with LDG IT-100 Tuner

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KE8CTH, Dec 30, 2018.

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  1. KE8CTH

    KE8CTH Ham Member QRZ Page

    Hello All,

    Got a question for all the Icom 7300 or LDG IT-100 owners out there. I just recently got the Icom 7300 added to my radio shack. I was using the Elecraft KX3 prior just using low wattage. The antenna I have currently is a G5RV up about 40ft high in an inverted v fashion. I have a "ugly balun" at the feedpoint about 8 turns at 9 inches in diameter using RG8X. My Elecraft KX3's internal antenna tuner could tune 80m thru 10m on the antenna no problem. When I try the Icom antenna tuner, it can only tune the 40m band. I began comparing the two internal antenna tuners together and I instantly found the problem. Icom's antenna tuner only tunes a 3:1 SWR while the Elecraft's can handle a 10:1. I did a quick experiment with the Icom and placed it into "Emergency Mode" which drops the wattage to 50W and also allows the antenna tuner to tune out a 10:1 SWR. I was still only able to tune the 40m band with the radio in "Emergency Mode."

    I obviously need some sort of external tuner to handle this SWR mismatch between the Icom and the G5RV. My concern is if I buy a LDG tuner, the manual states that it handles a 10:1 mismatch. According to my "Emergency Mode" test, it would appear that the SWR is slightly higher than 10:1. Any LDG owners out there with a similar problem? I am not opposed to using a manual tuner either if somebody has a good recommendation for the money.
     
  2. KU3X

    KU3X Ham Member QRZ Page

    Rather than putting a band aid on your system, why not correct the real problem. "Get rid of that hunk of wire you refer to as an antenna !"
    If you insist on using it, first replace the Ugly Balun (which is no balan at all) and put a current balun in its place.
    Next, if you insist on working with a band aid, get the MFJ929 auto tuner instead. It's a much better tuner, hands down. You really don't have to have the radio control either of the tuners, but it's nice if it does. Put the tuner in line and just send a carrier from the radio, the tuner will do the rest.

    By the way, running the radio at only 50 watts instead of 100 watts is no big deal. That's only a 3 db decrease in power and is about 1/2 of an S unit difference on most radios. So instead of an S 8 signal report you'll get an S 7 and 1/2.
    If I run high power portable, I never run 100 watts, I run 50 watts. If not 50 then QRP (5 watts) it is.
    Barry
     
  3. N7WR

    N7WR Subscriber QRZ Page

    Spend less money than you would for a tuner, buy some wire, build yourself an antenna that doesn't require a tuner at all. Lots of options. I currently have a multi band fan dipole that I built for very little money and it works fine
     
    NB3R and KU3X like this.
  4. W5WTH

    W5WTH Ham Member QRZ Page

  5. WA7ARK

    WA7ARK Ham Member QRZ Page

    Since everybody is touting their favorite, almost no-tuner required, home-brewable, multiband, coax-fed, wire dipole-type antenna, my favorite is the ZS6BKW (much better derivative of the G5RV). Chances are you could take down the G5RV and convert it to the better design...

    I have an IC-7300, and can use the ZS6BKW without even turning on the internal tuner on 40, 20, and 17m. There is a no-tuner sweet-spot low in the 80m band, but to get higher in the band, I have to invoke the internal tuner.
     
  6. W9KEY

    W9KEY Ham Member QRZ Page

    Yep - I'll echo other comments. I've got an Icom 7610, with the same 3:1 internal tuner specification and 100 watts as your 7300. As a new ham, I put up an 80-10 meter fan dipole - something like the Alpha Delta DX-CC with no balun other than six or seven turns of RG-8x at the feedpoint, which I've since found is pretty much useless (but probably doesn't hurt OR help very much). The antenna is only at 30 feet (using 3 trees) and tunes with 3:1 on 10, 15, 20, 40 meters and about 30% of the 80 meter phone band. It also "seems" to tune 6 & 12 meters, but with band conditions what they are, I've never found anyone to talk to and remain skeptical it would work very well.

    The point is - you can make a fan dipole like this for nothing more than the cost of some 12 gauge THHN house wire, a center section balun, PVC pipe for wire spacers, and the 80 meter coils (if you must go that route) - maybe $100 (or less). You will need a buddy with an antenna analyzer to tune each wire, or invest the money you save building your own antenna and NOT buying a tuner, toward your own analyzer - which is a very handy instrument to have.

    And another thing to consider (since I just wrestled with this) - the LDG IT-100 is only a 100 watt tuner. So if you think you might ever get an Amplifier - you will need to buy ANOTHER tuner with higher power capability.
     
    KU3X likes this.
  7. KE8CTH

    KE8CTH Ham Member QRZ Page

    I finally received my LDG tuner today and had great success with the G5RV. I was able to hit Puerto Rico 15 min after I unboxed it!! Then shortly after I hit Costa Rica on 20m.

    I do not think I will take that "hunk of wire down" anytime soon, hitting too much DX with it.
     
    N4FFL likes this.
  8. KE8CTG

    KE8CTG Ham Member QRZ Page

    How about all the other bands, did it flatten them out also? If so, I will be a believer in the LDG tuner paired with a G5RV. Please expound on your details.
     
  9. KE8CTH

    KE8CTH Ham Member QRZ Page

    I was able to fully tune 1.2:1 SWR on 6m, 10m, 15m, 17m, 20m, 40m and 80m. Truly an all band dipole. For the limited space I have in my yard, the G5RV is a rockstar. Hard to pass up.
     
  10. KE8CTG

    KE8CTG Ham Member QRZ Page

    So.............what you are telling me is that you wont have to yank that "hunk of wire" down and replace it with a 2K tuned yagi, hexbeam or 6 different dipoles in your limited space? Tell me it isn't so. Gotta love modern technology but some hate it, just how it is in today's world huh?
     
    KU3X likes this.

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