Ultralight Portable Antenna Quest

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KC8VWM, Jun 18, 2017.

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  1. AK5B

    AK5B Ham Member QRZ Page

    Way to go, Charles!

    Meanwhile, I didn't work a single station over the weekend's SMIRK Contest---6 meters died in Texas and a few other states shortly before the contest started on Saturday. Haven't heard anything since (although the east coast guys were working EU and SA like crazy). Such is life on the Magic/Tragic/Funny Band! It'll probably be wide open again the rest of this week...

    Have fun prodding the ionosphere with that nifty wand you made; every little bit of prop dust helps!
    KC8VWM likes this.
  2. WD0BCT

    WD0BCT Premium Subscriber QRZ Page

    Interesting home brew, however, it looks very similar to the Yaesu ATAS-25. This is a very compact and lightweight antenna which is tunable from 40M thru 2m and 70cm. However...just because it tunes does not make it an efficient radiator. I've attempted using the ATAS-25 from the field in both QRP and 100W HF modes with very dismal results. 8 hours of operating time on 4 different days. Essentially 8 hours of SWL. Some could hear me...nobody could copy. Yes it may have been due to poor propagation....but I heard lots of activity.

    I fear that compact/lightweight portable antennas are closer to dummy loads than antennas. That's my story and I'm sticking to it!

    I'm getting ready to field test a full size dipole using your laundry reel configuration. I just tuned it up in my back yard....a field test is pending.
    Last edited: Jun 20, 2017
  3. KC8VWM

    KC8VWM Ham Member QRZ Page

    As I am typing this I am now hearing station VK3CM in Australia on 14.214 using this cattle prod portable antenna.

    I have the antenna installed outside on the pool deck railing with just 4 of the wire radials attached.

    Here's a photo of the actual setup...


    It's actually pretty quiet for a vertical....

    Here, have a listen to this antenna and the station it's picking up from Australia yourself...

    Last edited: Feb 17, 2018
    AK5B likes this.
  4. KC8VWM

    KC8VWM Ham Member QRZ Page

    It's nothing like the ATAS-25 antenna.

    For one thing this antenna design is almost twice as tall as the ATAS-25 dummy load antenna and it has an all aluminum "Fat" antenna radiator, not a skinny and lossy stainless steel whip.

    Incidentally, an aluminum radiator conducts far, far, better than stainless steel does. Also, the "girth" of the radiating antenna element matters.

    Secondly, I am using a beefy #14 AWG copper wound wire coil and not a thin buss wire coil arrangement. Thicker conductors reduce losses and have higher power handling capabilities.

    Good luck with the laundry reel portable antenna. Let me know if you have any questions about it's construction and I am always glad to help.:)
    Last edited: Jun 20, 2017
    AK5B likes this.
  5. WD0BCT

    WD0BCT Premium Subscriber QRZ Page

    The ATAS-25 utilizes an aluminum whip....its essentially an aluminum sectional gun cleaning rod.
    I think the ATAS-25 would benefit from additional radials....one for each band is a little insufficient in my mind...even if all are deployed. The ATAS-25 is rated at 100W.

    I'm planning to do SOTA this summer and the ATAS-25 and FT-817 is about all I would consider deploying at a Rocky Mountain summit! I'll definitely pack additional radials.

    I will be operating with the dipole either tomorrow or Thursday from Chatfield State Park. I'll let you know how it goes.

    I do utilize a 20M hamstick vertical on a steel patio table in the back yard....on certain days it performs quite well....it does utilize a SS whip but has a fixed coil. When conditions are good a wet string will work!
    Last edited: Jun 20, 2017
    KC8VWM likes this.
  6. G3YRO

    G3YRO Ham Member QRZ Page

    Looks like a neat project, well done!

    It's amazing what will actually work . . .

    As posted somewhere on here before, when I was 14 I built a 2 transistor 1 watt (input) 160m AM transmitter into a transistor radio converted to Top Band (and used it's audio amp as the modulator).

    I just had a 4ft whip, obviously handheld, so no radials or anything . . . the whip just added capacity to tune the output coil wound on a bit of ferrite rod.

    Yet I regularly worked 5 - 10 miles with this . . . best contact was 20 miles !

    I have recently considered building a more modern little handheld DSB transceiver, but sadly there's so little Top Band activity these days I decided it wasn't worth it!

    Roger G3YRO
    KC8VWM likes this.
  7. AK5B

    AK5B Ham Member QRZ Page

    Charles's use of a much higher Q coil combined with a fat radiator invariably outshines commercial mediocrity every day of the week.

    The ATAS series has long been known as little more than a bunch of deluxe dummy loads in differing forms (albeit admittedly slightly superior to light bulbs or paper clips with a 50 ohm resistor connected.

    If anyone doubts what I say take a look at www.k0bg.com and search ATAS...

    When one does have good propagation why bother using a wet string, anyway?
    KC8VWM likes this.
  8. WD0BCT

    WD0BCT Premium Subscriber QRZ Page

    Hey thanks for the excellent webpage. I enjoy finding such a large source of opinions and hardware review in one place.

    The webpage is pretty much directed at mobile operation although there is a small section on portable operation. My interest, at the moment, is portable (vehicle camping and backpacking). The opinions regarding the ATAS units are directed at the screwdriver ATAS units which are aimed at the mobile market. I could not find anything directed at the ATAS-25 which is a portable unit, manually adjusted and with a much longer whip than the screw driver units. Just looking at the two devices (manual ATAS-25 vs the screwdriver ATAS-100-125) would indicate to me that the screwdriver ATAS units look questionable. I agree with this. I'm still thinking that the ATAS-25 with additional radials might not be a bad idea for the QRP backpacker. Every ounce counts...and the topography of your operating location is variable. The ATAS-25 requires very little real estate as well as being light.

    I was joking!

    As I experience more and more remote portable locations I'll have a better idea of whether I can employ a dipole or the ATAS-25. I'm not yet decided to totally abandon the ATAS-25. Perhaps Charles's ultralight portable design is the ultimate answer. At the moment I'm enjoying experiencing the different campsites I've attempted to operate from.
    KC8VWM and AK5B like this.
  9. AK5B

    AK5B Ham Member QRZ Page

    So was I!

    73, Jeff
  10. KC8VWM

    KC8VWM Ham Member QRZ Page

    This is exactly the antenna setup I was using on the deck railing during the contact I made with New Zealand and during the video recording of the other station in Australia.


    Last edited: Feb 17, 2018
    AK5B likes this.

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