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Thread: New Icom 7300 HF and G5RV antenna

  1. #1

    Default New Icom 7300 HF and G5RV antenna

    Hi and I am preparing to get my General Ticket and a new ICOM 7300 HF Rig (that has an internal antenna tuner) for DXing using SSP and CW (when I learn).

    I plan to get a G5RV antenna (http://www.amateurradiosupplies.com/product-p/11001.htm) with a 51 feet wire and 16ft, 450 Ohm Ladder line (that I will run perpendicular to wire wire dipole for use on 40M – 6M bands and mount it horizontally about 30 feet up on two backyard trees. Then fun 50 Ohm coax into house.

    I have a few questions.

    1) Even though I do not plan to use 80M or 160M bands, would I get better DX reception if I were to use a longer, 105ft wire / 35 ft ladder line, G5RV unit?

    2) Should I invest in a Balun (1:1 or 4:1) to connect the 450 Ohm ladder to 50 Ohm Coax? Or simple create a “balum” by creating a 8 – 10 loop with Coax?

    3) Should I / do I need to install a Lighting Arrestor (like http://www.amateurradiosupplies.com/product-p/13003.htm) within G5RV ?

    4) What type Coax should I purchase ?

    and finally

    5) Should I use only the amount of Coax cable to connect to HF System (approx 40 feet) or is it OK to get a 75 foot length and simply wrap and store next to Rig.

    Much thanks for help
    KC1ECW ([email protected])

  2. #2

    Join Date
    Dec 2008
    Location
    Elgin, Illinois
    Posts
    1,655

    Default

    Hello Dina,

    If I were to install another G5RV Antenna, I would want 80 through 6 meter RF coverage as we are entering the downward Sunspot Cycle and the most active bands will be 40, 60, 80 and 160 meters.

    I would purchase a 1:1 Balun and insert it at the transition between the 450 Ladder Line and 50 Ohm Coaxial Cable.

    Installing a Lightning Suppressor just after the 1:1 Balun (50 Ohm Coax Point) with a 10' Ground Rod would be a wise idea as you don't want that type of a Surge to enter your house or HF transceiver.

    You should use either RG-213/U or RG-8X Coaxial Cable.

    If I were to install the RF Coaxial Cable, I would allow only 5' Extra behind or adjacent to the ICOM IC-7300. You don't need extra RF Cable Coiled up next to your transceiver as it's a waste of coax and space for operating or placing other pieces of equipment.

    One thing that you should understand about a G5RV Antenna is the fact that it resonates almost perfectly on the 20 m band without an Automatic Antenna Tuner but it also is a compromise Antenna on all of the other bands so don't expect the G5RV to perform as well as a Rotatable Beam Antenna because it won't. If the wire is hanging North / South, the maximum signal will radiate East and West. If you choose to make the Apex or Center of 450 Ohm Ladder Line at 30 to 35' and let the wire slope downward as in an inverted "V" configuration, the Antenna will display a 360 degree Omni-Directional Pattern (prevent the wire ends from touching the Earth Ground).

    Dan
    WA9WVX

  3. #3

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    Dan,
    I VERY MUCH appreciate you taking the time to provide me with such useful and informative information. After 62 years, I've decided to enter this exciting hobby and it's guys like you who make if fun for newbies like me.

    Take good care,
    Bill in Blackstone, Mass

  4. #4

    Default Dan: Would you suggest a different antenna type ?

    Hi again and I mistyped my call sign last night. It is KC1EWJ and my name is Bill. Thanks again for info on dipoles and would you suggest my investiging in a vertical / single pole type antenna vs dipole for my plannned SBB and CW (after I learn code) DX communications.

    I understand thought that I dipole would be "more sensitive" especially if I installed as an inverted "V" as you suggest but perhaps a vertical antenna offers advantages.

    Even though we live in the country, my wife will NOT ALLOW me to erect what whe would think is an ugly thing on the house but I'm pretty sure I could get away with a single pole type mounted to side of home if it was less than 20 foot or so.

    What say thou and other Elmers out there :-)

  5. #5

    Join Date
    Dec 2008
    Location
    Elgin, Illinois
    Posts
    1,655

    Default

    Hello Bill,

    Sorry about the name confusion but I just looked up the call sign and it gave me Dina ... kind of blew me away as if the parents named their boy "Sue" (Old Johnny Cash song).

    Now comparing a G5RV Multi-Band Horizontal Dipole versus a Vertical Antenna. I'd stay with the G5RV as it's an easier antenna to put up, plus it's cross polarized to man made noise. The idea of lowering the G5RV is a bad one as all antennas work better higher up in the air. Installing a G5RV adjacent to your home is not a good idea because "if" you have aluminum siding, that metal could end up detuning the antenna plus having the radiated RF signal closer to your home, it may cause Radio Frequency Interference with Flat Screen TV & Stereo Audio Amplifier System, your Refrigerator and/or your Furnace as these items have electronic boards in the units, nothing like chasing your tail trying to resolve these type of problems. Most people do not realize that the newer Flat Screen TVs also radiate RF hash noise and there isn't much one can do for eliminating this noise other than keep your antenna far away these units.

    Using a Multi-Band Vertical Antenna comes with it's own set of do's and don'ts. A Vertical receives all man made noise besides the RF signals that you want to hear. Mounting a Vertical on a metal post driven into the ground will work but it won't work as well as having two sets of Radials Per Frequency Band and a lot of new hams don't understand this issue. The radials act as the other half of a Dipole Antenna and "if" you rely on earth ground for this, it's just does not work very well. Where would I install a Vertical Antenna? In the center of your backyard so I could install two radials per band and the overall length of the radials would equal a half wave length. The longest would go diagonally corner to corner so if you chose an 80 through 10 m Vertical, the longest radial would be 134' overall length for 80 m, 94' overall length for 60 m, 67' overall length for 40 m, 47' overall length for 30 m, 33' overall length for 20 m, 26' overall length for 17 m, 22' overall length for 15 m, 19.5' overall length for 12 m and 16.7' overall length for 10 m. The radials could be made from # 14 A.W.G. purchased at a Home Depot or Lowe's. To prevent the radials from getting in the way of your lawnmower or riding tractor, take a spade shovel and slit open the ground 6 to 8" deep placing the radial into that opening which will make it, Out of Sight & Out of Mind. The same can be done with Direct Bury RG-213/U coaxial cable when you route it up to the house. Make sure to install a Lightning Arrestor in your coaxial Line to prevent the high voltage surge from entering your house and ICOM IC-7300 transceiver. A good place to mount this device is at the base of the Vertical also driving a 10' Ground Rod adjacent to the Antenna mounting pipe and attach to both items.

    I have no idea how to recommend persuading your wife that it is okay to install wire antennas in your yard, some people have this thing about the Aesthetics of their property and how it will devalue the homes but it's never been proven. In fact I have a 120' tower in my backyard that's been up for 26+ years and my neighbors have bought and sold their homes without any problems. I also live in a country sub-division two miles west of the City of Elgin, Illinois. This thing about Aesthetics or Better Homes & Gardens is a bunch of Baloney. My wife & I maintain our home and yard to make it presentable for everyone. I've only had a couple of complaints after the tower went up but I told those people that they would need to take me to Federal Court because of my license and I mentioned that I hope they had financially deep pockets to fight the tower issue as I followed the County's Rules & Regulations all of the way and received a Permit to install.

    Dan
    WA9WVX

  6. #6

    Default

    Thanks Dan, great info. I started my study for General last night and must admit that it has more electronic questions and calculations than I expected. However, I am certain I will be able to pass after some time reading purchased ARRL General Ticket Book and Questions guide. I will get back to you when I'm ready to purchase but think I will invest in new Icom 7300 (unless reviews look bad) and a 40 - 6 meter dipole mounted at least 20 feet up two trees that are about 15 feet form our wooden house (no aluminum). I will also install lightening arrestor between ladder line and 50 Ohm Coax.

    I will get back to you after passing test.

    Again, thanks much for taking time to help :-)

  7. #7

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    Hi hamwillyt,

    Welcome and best of luck to you. Study the online tests and you won't have much trouble passing. As for the Icom 7300, it is a new radio and the jury is still out on it'. Another good choice for a rig in that price range would be Kenwoods TS-590SG. Excellent receiver, excell transmit audio.

  8. #8

    Default

    Welcome and best of luck to you. Study the online tests and you won't have much trouble passing. As for the Icom 7300, it is a new radio and the jury is still out on it. Another good choice for a rig in that price range would be Kenwoods TS-590SG. Excellent receiver, excell transmit audio. 73-Rich, K0PIR

  9. #9

    Join Date
    Jun 2015
    Location
    Pittsburgh, PA
    Posts
    5

    Default

    Bill, welcome to the hobby, and good luck on your upgrade!! The 7300 looks like a really nice rig, and I'm sure you'll enjoy it. I run a 7100 with a G5RV Junior, and it performs pretty well. However, you should be aware of a few limitations.

    First, the G5 is a multi band antenna, not an all band antenna. Mine works well on 40, 20, and 10, but poorly on the other HF bands. You can forget about 160, 60 or 30. 17 and 12 are okay at best. In addition to the G5, I run a 43' vertical (with a tuner), and that gives me good coverage of the bands the G5 is lacking on.

    Next, while the 7300 is a cool radio, the internal tuner has a maximum range of 3:1. It's really more for "trimming" a resonant antenna. It really doesn't have the range to effectively match a G5. You'll really need an external tuner. External auto tuners have a tuning range of about 10:1, while most manual tuners will match almost 30:1.......

    Finally, while it's generally better to only use as much feedline as you need to reach the radio, the G5 depends on a certain amount of feedline loss to obtain a match. Most manufacturers recommend a minimum of 70' of coax with a G5RV.

    Hope this helps. Good luck, and have fun!!!

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