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Good HF No Radial Vertical?

Discussion in 'Amateur Radio Equipment Reviews' started by AA9ZZ, Jun 14, 2008.

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  1. M0ZMO

    M0ZMO Ham Member QRZ Page

    Comet CHA 250

    I would love one of these antenna`s but keep being put off by reports, there is no way I can elevate it too 35 ft, I have a Sandpiper v9 at the moment and to be quite honest it works ok thats it, and every now and then you have to replace a TRAP i HAVE BEEN THROUGH 5 SO FAR AND AT £30 EACH I may as well buy a more reliable antenna.
     
  2. NL7W

    NL7W Premium Subscriber QRZ Page

    My radial-less backyard home-brew vertical works great. It's a 40M halfwave inverted-L, matched with a low to high-Z "L" network mounted in an ammo can. Of course, I have quite the coaxial coil RF choke near the antenna feed point to keep the common mode currents tamed.

    Try one... they work tremendously. ;)
     
  3. PA1ZP

    PA1ZP Ham Member QRZ Page

    no radials on vertical

    Hi all

    J-antannas do not need radials and vertical Zepp antennas do not need radials.

    But the problem is that they are half wave verticals and are very big.
    For the comment that every day comunication signals are high angle is not correct.
    Only signals on the low bands (80, 40 mtr) can be high angle sigs.
    For the bands 20 mtrs and up low angle take of at your antenna is a must.

    A couple of friend of me and I have experimented a lot with verticals in comparison with horizontal dipoles.
    On 80 meters most of the time the 1/4 wave GP vertical will beat a 33 feet high half wave dipole on distances above 600 miles.

    On 40 mtrs 1/4 wave GP vertical will beat the half wave dipole at 33 feet at abt 1000 miles distance most of the times.

    I would advise to use a seperate antenna for RX on 40 and 80 meters when you are using a vertical.
    Verticals tend to recieve more QRM and QRN.

    Most verticals have a big advantage over horizontal antennas that they radiate in all directions and do not have deep nuls in some directions as horizontal antennas often have.

    And verticals do not need to be placed that high above ground.

    You can tune SWR but You CAN NOT tune the radiation patern.

    73 Jos PA1ZP
     
  4. W0ZPE

    W0ZPE Ham Member QRZ Page

    Trust me...you don't need radials on the GAP Titan DX and the factory recomends you do not install any. The GAP is a vertical dipole. Mine is used exclusively for 40-meters and it's DXed around the world.
     
  5. AC0FP

    AC0FP Ham Member QRZ Page

    K2TL, has described my vertical doublet (dipole) very well. It is 43' high with the 12 Ga. wire elements cut for twenty meters and fed in the middle with 450 ohm window line. EZNEC software indicates it should work pretty well. The widow line comes away from the tree for about 30' and then angles down to where it comes into the house. The antenna itself is pretty "stealth" but not so much the window line.

    To the OP, I don't know if you have a tree or not but if you do you might try a vertical doublet. K2TL is right when he says putting it up and feeding it is a PITA. I think feeding it with 300 ohm line might make it more "stealth".

    I have a horizontal doublet in the backyard and can switch between the two antennas which is really nice.

    Good luck,

    Frank
     
    Last edited: Sep 9, 2009
  6. G4NKX

    G4NKX XML Subscriber QRZ Page

    No Radials?

    In answer to the "ORIGINAL" question

    Is there such a thing as a good HF no radial multiband vertical?

    NO - It is also my understanding that ANY quarter wave HF antenna should have Radials, or a counterpoise attached.
    There are some antennas being marketed with 6:1 or 9:1 baluns attached at the base, (no radials) and given the physical length of these things may well indeed work, but not as efficiently as one with radials attached where current distribution throughout the system is even, I suspect they probably work to a degree, it would be interesting to know just how much of the power applied actually radiates - if they're ground mounted surely you NEED radials? LOTS of em.
     
  7. W7CDX

    W7CDX Ham Member QRZ Page

    Agreed - I'm using a Cushcraft R-6000 on the roof and have made several International contacts with it. SWR is 1.3:1 or less on all bands without the use of a tuner.
     
  8. W0UZR

    W0UZR Ham Member QRZ Page

    Good HF no 2nd Half on Dipole?

    A multiband dipole will work very well with just half of the dipole that the center wire of the coax connects to?

    It should work GREAT !!
    RIGHT?

    That makes exactly the same sense as a vertical with no radials.
     
  9. K3DAV

    K3DAV Ham Member QRZ Page

    I use a Comet CHA250B. This is a surprising antenna. Anyone who says it is crap and doesn't work, did not know how to install it and use it, or they had a bad one which is very rare. This is a great little antenna and built very simply. I have worked the world into all continents with good reports on 80 through 20 meters.

    Mine is on a 20 foot mast off the ground. No radials required and you will have a 1.5 SWR or less throughout the entire HF spectrum. The thing about HF verticals that we sometimes forget is, this is a compromise antenna. Those who expect it to work like a yagi or a perfectly cut dipole at 50 feet up, are expecting too much and should never use one. You may not give them 30dB in Australia, but I gave them an S-9 to 10dB signal.

    Now here is the option that helps. They say you do not need radials or counterpoise wires, and they are correct. I talked all over the world for a while that way. But one day I got the idea to cut 2 counterpoise wires. One for 75 meters, and the other for 40 meters. Both 1/4 wave of the frequency. Connected them to the U-Bolt on the antenna's mount to the mast. The wires helped a little but noticeable. They were worth the effort to make and install them.

    The coil in the base is basically a dummy load with a 50 ohm feed-point. They take a tap off the coil for the main 23 foot element. So the SWR is always 1.5 or less. The antenna works, and works better than I expected for what it is. I have had hundreds of good DX contacts with 100 watts. Even broken through some big power pile-ups. If you are space restricted and want a good antenna that will get you on HF with contacts, the Comet CHA250 will do the job.
     
  10. N5VEG

    N5VEG Ham Member QRZ Page

    Sounds good but a bit pricey for a compromise antenna.

    I use the S-9 type. Actually it's the original 31 foot fiberglass pole made by Walter Speith. It's over 20 years old and I put the wire inside the pole. I use a coil to load it up on 80 meters and have 16 radials and wire mesh under the pole for counterpoise. It receives and talks like a compromise antenna! But it's oh so easy to take down in a storm.

    I have never seen a vertical that works good without some form of counterpoise.
     
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