Radials with trap vertical

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by WB3CQA, Oct 9, 2019.

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  1. WB3CQA

    WB3CQA Ham Member QRZ Page

    I am using a ground mounted Hustler 5-BTV with a DX Engineering Current Choke. It seems to be performing very well, in spite of terrible band conditions. Right now there are only six short radials being used. Space is rather limited, and radial lengths would be mixed from only a few feet to twenty or thirty feet. Do radials improve received signals, transmitted signals, or both? I can hear DX stations much better than they can hear me (I'm only running ~100 watts).
  2. K7TRF

    K7TRF Premium Subscriber QRZ Page


    With a ground mounted 5-BTV you should try to add as many radials as possible. Don't worry too much about length nor about symmetry if the antenna is squeezed into a corner or tight place just focus on getting as many radials down as you can manage. Sure if you can make them reasonably long then that's great but the main thing is a lot of radials and making sure that at least the area near the base of the antenna has a lot of radial coverage.
    KU3X, K0UO and K3UJ like this.
  3. AJ5J

    AJ5J Ham Member QRZ Page

    Both. The more radials the better, and they needn't be a certain length when ground-mounted. Lay down as many as you possibly can and remember lots of short ones are way better than a few long ones---the current distribution is highest near the base of the antenna.

    Suggestion: Buy two 500-foot rolls of wire at Home Depot or wherever and cut as many 10'-15' radials* as they will allow. Lay them out in a spoke pattern all the way around if you can. If not, even a half circle will do. The main thing is to get a lot of them down and think of them as "shielding" your fine antenna from ground losses.

    Your SWR should rise to about 1.6: 1 and present close to a 37 ohm load at near zero reactance if done well---this is good!

    *As I said before, the length is not critical; it is the quantity of radials which is more important. A mix of 8', 13' and 21.4 feet or whatever is all fine. All the same is fine, too (say 11 feet or 20 feet, whatever...)

    Get some knee pads if you're an old codger like I am; they'll come in handy!


    KU3X, K0UO and K3UJ like this.
  4. AJ5J

    AJ5J Ham Member QRZ Page

    Wow, Dave! I was having trouble with my internet connection which slowed my reply down by a few minutes---so my reply actually posted well after yours---a kick to see that we both replied with "Both." (!) Funny how things work sometimes!
    K7TRF likes this.
  5. AI3V

    AI3V Ham Member QRZ Page

    For the most part more radials will make the received signal and noise equally stronger.

    So you will NOT see an improvement in s+n/n.

    The big improvement is in transmit.

    K3RW, K0UO and AJ5J like this.
  6. KB1CKT

    KB1CKT Ham Member QRZ Page

    Butternut recommended to make the radials about as long as the antenna is tall. If you read up on image theory (which is how this antenna works, with a ground plane) then it kinda sorta makes sense--as the plane gets longer, the antenna "sees" less of it. For a fixed amount of wire, it's better to concentrate it towards the base of the antenna, where current is the highest.

    But on mine I figured a few long ones wasn't going to hurt...

    Also, as you add radials you may find the apparent resonance of the antenna shifts. You may need to retune the antenna. An analyzer will be nice to have.
    AJ5J likes this.
  7. KB3FEI

    KB3FEI Ham Member QRZ Page

    A non-answer answer: one of the best books on vertical antennas is "Low Band DXing" by John, ON4UN. I have a 6 band Hustler, with pvc/wire add-ons for 12 and 17. You're getting good advice in this thread. Enjoy.
    AJ5J likes this.
  8. W6GMT

    W6GMT XML Subscriber QRZ Page

    Just finish putting up a 4 band trapped vertical with 32 radials some 20 feet some 32 feet. work's very well. Had a Wolf river portable vertical in the camp ground all summer with 16 radials worked well but adding 16 more radials to the 4 band for the winter made a very noticeable difference, more is better, I an going to add at least 12 more radials if I can before the snow fly's some will be only 10 feet.
  9. N0YPD

    N0YPD Premium Subscriber QRZ Page

    Double post
  10. N0YPD

    N0YPD Premium Subscriber QRZ Page


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