Screwdriver antennas.

Discussion in 'Mobile Radio Systems' started by N0IOP, Oct 10, 2019.

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  1. NH7RO

    NH7RO Ham Member QRZ Page

    You might want to install a Breedlove foldover mount for times when you are driving through Charleston or anywhere with low-hanging branches. Of course this will then preclude operating while in motion but might save some wear and tear on your installation.


    WA8FOZ, K0UO and N4UP like this.
  2. N4UP

    N4UP Premium Subscriber QRZ Page

    Good advice. I have the fold-over mount installed and it works. The problem is me. I keep forgetting to fold it over when driving in "those places" ... and yet I remember to take a spare whip with me. 98% of my mobile contacts are while parked on the side of the road, so it makes sense to fold it over while in motion. I just need to get in the habit of doing that.
    NH7RO likes this.
  3. NH7RO

    NH7RO Ham Member QRZ Page

    Roger that. What I do is sort of the opposite---98% of the time my current Scorpion "top" of choice is an 8-foot fiberglass whip which is folded over and tied down to part of my roof rack. The times I am QRV are generally specific when I make a trip to the beach solely to get on the air.

    Once parked, I untie it , raise it to position, install a couple of elevated radials (tied off to two signposts on either side of me at a spot right on the water) and I'm all set. Although I cary a couple of radials cut for 20 and 40 meters I have found that there's no need to change them when I switch bands---the 40m ones do well on 20m so I don't have to hassle with redoing them. I also have my car's hood, exhaust, engine, rear hatch and Scorpion base well-bonded together with copper strap or 1/2" wide tinned strap made from LMR-400 shielding.

    HF mobile is a very different kettle of fish compared to weak-signal VHF/UHF---which I used to do a lot of---so I have learned that bonding and choking of feed and control lines is essential. The common mode noise is enough to drive anyone crazy otherwise; another reason I prefer to never or seldom operate while in motion.


    N4UP likes this.
  4. KF4ZGZ

    KF4ZGZ Ham Member QRZ Page

    I built my own, and have built several more.
    I Ran the same one for many years.
    I did have to replace the coil once. I had it on my off-road rig when 4-wheeling..... trees don't give!
    Hamsticks don't even come close!
  5. KM4DYX

    KM4DYX XML Subscriber QRZ Page

    Have you ever replaced the whip with a quarter-wave horizontal or slant wire?
  6. W5LZ

    W5LZ Ham Member QRZ Page

    After a lot of years operating HF mobile I've found that any/all HF antennas are going to take a beating. So, making whatever allowances you can for that, cunt on it not lasting forever. The more 'heavy-duty' you can make it, the better. And that includes the mount! I've broken several ball-mount bases. If it's plastic count on it breaking. No idea what the -old- ball-mount bases were made of but they hold up very well.
    It looks kind of odd, but guying a screwdriver antenna is a -very- good idea! Do it right and you can use those guys to support 'cap-hat' radials (make sense?). And you will find that there are a few drive-throughs that you just can't drive through anymore. Oh well... ain't no step for a stepper, just a PITA.
  7. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    Yes go with the Breedlove foldover mount
    I run mine at 45 degrees a lot of the time which lowers the top of the antenna down, I'm not using a capacitor hat right now but a long whip so it works for me. Also they make a great heavy duty quick disconnect for the whip part which I allow you to get into a garage
  8. NH7RO

    NH7RO Ham Member QRZ Page

    No; I don't see much point in doing that especially when I am by saltwater. I am after low-angle enhancement while I can get it.

    Furthermore, adding a quarter wave to the coil and bottom mast would make it longer than a quarter wave (at least electrically).
  9. KM4DYX

    KM4DYX XML Subscriber QRZ Page

    Is that to protect the antenna?
  10. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    Yes, and on the lower bands I run a longer whip making it more efficient. If you believe in antenna shootouts, I actually had a +2 S unit better signal on 40 meters at 45 degree, midday. 300 mile path from Quartzsite Arizona to N California in Jan.
    After the dealer absorption goes away the vertical at 90 degrees always works better. K0BG has done some modeling on this and is inefficient as most antennas are as gently should not be possible. But I proven it on several antenna shootouts for "what they're worth", remember this a very unusual sunspot cycle of past couple years with low D absorption on 40 meters in the day time.

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