Threading wire along a wooden deck

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by AB2T, Jul 5, 2020.

ad: L-HROutlet
ad: l-rl
ad: Left-3
ad: abrind-2
ad: Left-2
ad: Subscribe
ad: L-MFJ
  1. AB2T

    AB2T Ham Member QRZ Page

    I don't live in a HOA but I do have nosy neighbors. Even a folded dipole in the yard will attract attention. I know, sc**w what the neighbors think. Still, even before I go to dipoles and even end-feds, I want to try stapling 300 ohm twinlead below my wooden deck. There's plenty of surface area. and I already have a balun ready to go. I run barefoot (~120w, old hybrid) and use CW only. Is this workable?

    73, Jordan, AB2T
     
  2. N8AFT

    N8AFT Ham Member QRZ Page

    The law of Physics says yes and amen.
    It will radiate. Try it, what hv you to lose but some of yer time?
    K3WWP's QRP CW web-site has info on his simple wire antennas... worth a look OM...
    Can you tuck some stealthy 18ga wire under the eaves? Up the corner of the house?
    Those are great possibilites if you hv plastic siding. Twinlead fed 18ga dipole or invee?
    I'd recommend an EFHW as a last reort only but rated at 800w and 132ft long. MFJ? FB.
    (My pro-made 200w Un-Un failed due to heat stress and wiped out my 6146 PA on my TS830)
     
    Last edited: Jul 5, 2020
    AK5B, N0TZU and AB2T like this.
  3. KC8QVO

    KC8QVO Ham Member QRZ Page

    As in the 300 ohm twin lead is the feed line or the antenna? If it is the feed line - what kind of antenna is it feeding? If it is the antenna - the term "deck" means low to the ground. Even if it is an upper floor balcony that is still "low". Unless you live in a high-rise building.

    As for "stapling" the 300 ohm twin lead - metal staples are going to interfere with the impedance of the line at RF. Electricity wouldn't matter, like stapling Romex to the floor joists in a basement crawl space. You aren't stapling romex - you are stapling a line carrying RF, not electricity.

    If you are using the twin lead as a feed line the twin lead provides insulation to contain and conduct RF within it by way of an electromagnetic field around the line when the RF is flowing. That is why balanced line (any - 300 ohm twin lead on the smaller end up to 600 ohm true ladder line) has to be kept away from objects - even tree branches - to work most efficiently. By stapling it you are putting metal right across the parallel wires that make up the transmission line.

    So there is a lot of theory that you are going to be disturbing by using "staples" on balanced twin lead. Whether it is the antenna or the feed line there will be interaction. What negative affects will that interaction cause? For a feed line application - you'll have attenuation. For an antenna application - you will have shifted/disturbed impedance.

    Will any of the negative affects prevent you from making contacts? I don't know. Try it.

    My thoughts - it does not sound like a good option for an antenna. I suspect the elevation is too low and there is too much interaction with "stuff" around it (deck frame, even though its wood, nails/screws, the house, etc) on top of it being low.

    Will you make contacts on it? If you try hard enough I suppose anything may work. For the record, I have decoded 20m FT8 signals without even having coax plugged in to my HF rig. That does not mean that the radio sitting on the desk by itself with just the power cable and audio cables is a good receiving set up - just that there was enough RF floating around that it could pick it up. Your goal should be efficiency - not just throwing something up with the hopes of getting a contact or two. However, that is part of the fun of ham radio - experiment and see what works and what doesn't.

    If you have the ability to do a side-by-side comparison between the set up you propose and another antenna that might give you a good perspective on its' effectiveness. Case-in-point here - I had a wire set up for 160m over the winter. It went up to a tree at an angle then bent 90 degrees to another tree. It was sort of like a horizontal L, but the short side of the L sloped from the ground up to about 20 feet up. It was the best 160 meter antenna I have used in my own station set ups (yes, very low but its all I can do here - and was really pushing things even still). It would load up on all bands. I had an LDG AT-200Pro tuner at the feed point (in a box, power to it is run through the coax). It seemed pretty deaf on some bands. So I hooked up another antenna - the screwdriver antenna on my truck. I did an A/B comparison on 20 meters. The difference was quite large - the screwdriver antenna outperformed the long wire I was running on the low bands. I was running a lot of FT8 since about November or early December last year and the comparison I did was on FT8 on 20 meters. The difference in signal strengths and band noise was quite noticeable.

    My point - if you have 1 antenna you won't be able to make any comparison on if it is efficient or not, other than what you see on a spectrum display (if you have one) or what your S meter shows, or what your signal reports are from other hams. What you might find is that antennas can perform well on some bands and not others - which was what I was trying to illustrate here. If you only have 1 antenna and its terrible where you want to operate - what are you going to compare it to in order to know how bad it really is? In my case - the long wire isnt up right now - the support lines broke so I took it down, but that was well after I already had made my comparisons. So I know it doesn't work well on the higher bands and I know there are better options that I can do. The challenge for me at the moment is to get an antenna that will run 75m. The wire I have at the moment doesn't work well there, even though I cut it for the band (with the use of a tuner - there are lengths to avoid for certain bands, I think mine is 67 or 68 feet to load everything down stream of 80/75).
     
    AB2T and AK5B like this.
  4. AK5B

    AK5B Ham Member QRZ Page

    26-gauge Davis RF Polystealth is so thin and stealthy it's practically invisible once aloft.* Forget stapling twin lead UNDER anything and get some Polystealth UP in the air where it will do you and your rig some good.

    * Here's a photo of it that I used for my two-radials-per-side 17/20m portable antenna. The photo was taken from only a few feet away yet it's still hard to see so close:
    IMG_8118QRZ.jpg The #26 is attached to thin Dacron rope at both ends which then goes to one half of a DXE Resin Support Block (used as a spacer) and the orange fiberglass driveway markers placed about 38-40 feet apart.Look closely to the area left of the coax feedline attachment to see just the thin wires barely visible.


    Damn the torpedoes, screw the nosy neighbors and enjoy being a ham to the fullest!

    73,

    Jeff

    (The 2nd attached photo below shows more Dacron rope than the #26 wire so I swapped it for the large photo above as a better example)
     

    Attached Files:

    Last edited: Jul 5, 2020
  5. WR2E

    WR2E Ham Member QRZ Page

    With all the cover you've got there I'm SURE you can get something up that they won't even notice.
     
    Last edited by a moderator: Jul 6, 2020
    AK5B likes this.
  6. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    The best antenna is one that's IN the AIR and ON the AIR.
    Give it a try but don't get your expectations very high.
    If it's a lower deck I would say it's a complete waste of time.
     
    AK5B likes this.
  7. WA9FZB

    WA9FZB XML Subscriber QRZ Page

    If you're thinking of a low folded dipole, it will "work." "Work" though, is a relative term. If you are on 40M, you actually may make contacts. For a while I had a full-sized 40M dipole in my back yard, at the mammoth height of 8 feet above ground. I made CW contacts over 25-30 states and close-in DX like Mexico from Chicago. I was using an FT-840, running 100 watts. Was it a great setup? Far from it. But I was on the air, making contacts. Of course, I had some issues tuning the antenna due to nearby structures. I had a lot of RFI/QRN issues. Couldn't work any "real" DX. But, I was on the air and had a lot of fun.

    Ultimately I replaced a trap vertical that had failed, and now I can make many more contacts, still with only 100 watts on CW.

    BTW, another trick I have used to fasten wires to wood, rather than staples, has been to staple a cable tie to the wood, then fasten the cable tie around the wire. That way, the staple does not straddle the conductors of twinlead. Don't know if it is any better, but it made me feel better.
     
    AK5B likes this.
  8. AB2T

    AB2T Ham Member QRZ Page

    Wow that's really thin! I could build a 30m dipole and make it practically invisible. Thanks Jeff for the idea.

    73, Jordan AB2T
     
  9. AK5B

    AK5B Ham Member QRZ Page

    Glad you found this info so useful---yes, it really is about invisble---and 100 watts through it is fine, too.:)

    73,

    Jeff


    P.S. Davis RF sells by the foot and ships direct, too---give them a call when they're open or check them out online:http://www.davisrf.com/antenna-wire/index.php
     

Share This Page