ShopTalk Sunday: HF Antenna Drone Installs

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This being Rum Sunday and all, I’ve done a couple of reports recently on the use of drones in a prepping and survival situation.

In these, I have extoled the virtues of drones, even the cheapie $99 sort that I learned to fly on: an internet “deal” which worked out well.

With a drone, a prepper can easily (and quickly):

  • Hang ropes through high limbs of trees
    • Which can be used for bear-proof food caching and
    • Which can be used for off-ground hammocks and hammock-tents
    • Hiding from search teams
  • Drones can search out food sources over both water and ground.
  • Drones can “look ahead” on trails (limited to line of sight (LOS) and typically 1 km. or less with a cheap drone or 3-5 km. with a grownup priced drone.

What I haven’t done is laid out a methodology for their use as HF  radio antenna launchers which I now have plenty of experience on.

Drones and Trees

Drones come in several “gimbal” configurations.  A cheap drone (mine, 2-axis) will not perform well in the wind.  This means you need to await calm winds.  Fortunately, the wind around here doesn’t pipe-up until about 10 AM most days.  (We’re in Wind Zone 2, while on the plains up northwest of us, (abilene) Wind Zones can run 4+.)

In these higher wind zones, the more expensive drones (which will hold their own in winds of modest size and remain stable) are the right tool.

The second factor in drones is flight time.

When you go shopping for drones (in normal applications) you will likely buy based on whether it has FPV (first-person view means pilot seat view), the resolution and range of the camera.  Anywhere from 720P resolution (barely single cam) good for under 1 km. of streaming range all the way up to 5G with 5 km. 4k streaming range plus pilot cam.  When you get into these, you’re talking real money.

But we don’t live forever, either, so WFT, right?

Dwell Time 

How many minutes of flight is either a HUGE deal (surveillance, camera work, range and so on), or it’s a nothing-burger.

A cheap drone (Ure’s choice) is maybe good for 12-15 minutes of flight time.

The higher-end drones have more flight time. 33 minutes depending on budget.

But, except for the ability to handle winds (which are always different aloft compared with ground-level) are not much of an advantage.

That’s because a higher dwell time (on targets) means a higher battery weight.  For the installation of antennas (over the dead-to-nuts top of trees) its really all over in 5-minutes, or so, of flight-time.

Although a 650 MAH (milliamp hour) battery came with my drone (12-15 minutes) the optional, Amazon-sourced 1200 MAH battery is a good bit heavier.

If you aren’t off the ground, and over the tree in 5-minutes, and the drone shut-down and being released on the far side of the tree, you better work on flying skills first.

Installations

Let me sequence you through one of the installations.  I decided that the long-end of Super-Antenna needed to be move from where OM2 (and son) got them last year (ladders and swinging pop bottles) up to the fly-over tree position now:

This end of the antenna went from “living in the blue box left” up to living in the blue box upper right.

Zooming in on the tree top, you can get an idea where things run from this:

Nothing warms a ham radio operators’ heart more than having to use telephoto camera options to see the high end of their antennas!

But There Are Ugly Consequences

One of these is that the “typical” OCFD (*off-center fed dipole) antenna changes impedance as you raise over 40-feet, or so.  This is because the ground under antennas is part of the antenna system.  Ground has just so much resistance and the further the antenna is removed in the vertical axis, the more impedance changes.

So does the resonant frequency of the antenna, as well, as a result.

A (used) BuxCom 3 KW OCFD that flew fine direct into Coax from the top of the tower, changed to a much lower resonant frequency and required some retuning at the 50-foot level, in one of the other antennas.  Hand me the telephoto?

This antenna is almost a flawless match at 35-38 feet above ground, so you can see how the returning and tweaking figures into things at 60-feet plus.

A Useful Shop Made Tool

The key to employing a lifting drone for antennas and other “high work” is to make up a simple system to retrieve the carefully chosen lifting line.

For this purpose, I used a high quality 20-pound test woven fishing line. 200-yards of SpiderWire Stealth Braid Fishing Line is about $16-bucks on the Zon.

To make the line-winch, grab whatever seems handy from your hardware assortments.  An inch to inch-and-a-half bolt (3/16ths is fine or M-whatever).  Then a couple of washers, and a rubber grommet with another washer.

What you” fashion-up is a wrench adjustable dry clutch for your variable speed drill.  Like so:

You chuck up the bolt (Charles if you haven’t worked with one before) and tighten down the nut holding compression on the fishing line spool.  This woven line shit is impossible to see, so don’t lose track of the end!

To launch have your scantily clad assistant simply point the drill at the drone and the line will fall off the end just fine.

To rewind, simply hold the drill at right angles to the line and turn on the drill.  After a large rannygaboo of line balls up in your hand, either change the line to the other side of the drill or hit the reverse button.  Duh. It’s guaranteed to tangle, lol.

Use care (as your assistant leaves, tired of holding your drink and being ignored) when you try to speed things up.  Fishing line rolling in at high speed is like owning your own, personal, paper cut machine.

Although even the paper cut wasn’t bad.  Why, it brought me head-on into the idea of making a fishing line bandsaw for Styrofoam.

I’m too old to patent things anymore, so have at it.  I figure you ought to be able to get 63-inch loops of knotless fishing line made in Asia for less than a half penny per billion.

Off to a fine weekend of antenna tuning.  Whoo-hoo!

[Disclaimer:  Ham radio is not a hobby.  It’s a disease.  Though less contagious than Covid.  Main spread-vector is math and geek genes.  But ham radio does come with several boxes of excuses which are usefully employed as “reasons” for new tool purchases.  Ham radio with higher power is useful to explain-away small fires in the shop.

On CW (Morse code) into the Yukon Territory on 20-meters, there was no difference between SuperAntenna (oriented east-west) and the Buxcom north-south.  Altitude though it a HUGE deal in antennas.

Just remember, an OCFD antenna with a 4:1 balun (balanced to unbalanced toroid coil lash-up) that matches perfectly at 40-feet, will need to be adjusted to a 6:1 balun up at 70-feet.  Because the impedance will rise from 200-ohms in the 35–40-foot range (a 4:1 impedance conversion off 50-0hm coax) to 300-ohms (or 6:1 off 50-ohm coax) at the 70-foot level.  You can model all this is EZ-NEC, depending on the severity of your radio contagion.

Height is always good (higher is better).  However, as the occult fairytales have it (in the ARRL Antenna Handbook), sometimes the additional altitude impedance change may not be favorable.  That’s because take-off angles of radio signals (measured as elevation above the horizon) are generally lower, the higher you go.

See, high-angle isn’t bad (the Church of Near Vertical Incident Skywaves meets on 80-meters most mornings for coffee).  They are the Prophets of Counterpoise and “keeping daytime take-off angles high.”  My personal religion is the 10-Degree Inventists, who can’t think of anything better than welding the horizon with big ERP numbers.

But to each, their own.  Is 20 open, yet?

And One News Comment

I don’t usually  offer these on Sunday (blasphemy and all that), but here’s the plan of the day:

Elaine and I will be doing rum shots today ahead of another splendid Sunday prime rib roast.  And playing in the recording studio will be Chicago’s “Does Anybody Really Know What Time It is?“

The news item driving?  “Watches worth $2 million taken in downtown smash-and-grab as retail raiders strike again and again.”

If you don’t know what time it is?  Here’s a hint.

Late.

Cue Bobby Hutcherson, next…then maybe some Herbie…yeah – Rum Sunday.  Amad rolls nice with it, too…

Write when you get rich,

George@Ure.net ac7x

44 thoughts on “ShopTalk Sunday: HF Antenna Drone Installs”

  1. the cheaper drones use wifi!!! I am trying to use a long distance wifi antenna to send a DEAUTH to a drone and make it land.

      • Thanks ffg or sharing that Hank…Years ago before you could buy them I was laid up and being bored with network television I made a satalite dish receiver and low noise amplifier..after seeing it . I started reminiscing about the lna unit I made ..the cantenna looks quite a bit similar to the lna I built missing a few things. .. . It was crude but worked I used a coffee can lol..
        Lol the dish dwarfed the house..it was made out of chicken wire and window screen.. made a template for the curve then quartered it made the dish..
        A couple of years after I made mine they started selling them..
        Lol.. today not a chance you can buy one cheap lol..

  2. “you better work on flying skills first.”

    Lol.. I was given a drone several years ago.. Huge thing about 18 inches in diameter .. I never tried it. I guess I just didn’t have any interest.
    Then my young grandson had an interest in flight. So we went to the sewing shop got some rip stop nylon and made a little dirigible and a small hot air balloon. Made a few paper airplane models .. Then he spotted that drone on the shelf. His eyes lit up..he could make that thing do tricks.. And high. It didn’t have a live view camera.. The one he has now does with a controller that hooks up to his phone.. And a lot smaller flies longer and faster..

  3. This began yesterday. Yep, when inflation is ramping up and there are meat shortages … (somebody) got the bright idea to start cutting back the natural meat source. Wow

    Better up your survival game if this crap catches on. -wonder if that sterilizer gets passed on if you just happen to eat a deer that’s in the “research program” hmmm. Damn

    https://www.cleveland.com/community/2021/12/south-euclid-set-to-start-deer-sterilization-research-program-dec-11.html?outputType=amp

    • Jeez Louise. Half the body shops in Texas would close were it not for the deers. Not to mention the billion dollar deer rack bolton kits for the fronts of pickem up truck.

      Do we all have to be stupid at once?>

    • Dear Pathfinder Bob,

      I read the informative article in the link you posted about an urban area looking to apply sterilization as a “non-lethal” method of eliminating its deer population over the course of several seasons.

      Ironically the company and its owner contracted to oversee the deer program can be found in the US patent records. A year ago they filed a patent on a trap designed to capture nuisance feral swine. According to the horse’s mouth of said patent, there was no mention of the pigs being lined up for subsequent sterilization.

      However, the name of the company is White Buffalo Inc. I don’t know if it follows from the path of “The Legend of the White Buffalo”. The creator speaks in mysterious ways?

  4. George,
    I’ve had a G5RV up about 20 ft in the trees around our house for some time. I’ve considered trying to go higher and like your drone approach.
    One concern I have is lightning – I manually disconnect the coax when not using the radio.
    Is there a point of diminishing returns where the additional DX isn’t worth the higher risk of a lightning strike?
    Has your rig ever experienced a lightning strike and if so, what was the damage?
    Thanks.

    • Several items here.

      First, an antenna is never too high under you get over 1 wavelength in height. That would be about 260 feet for an 80 meter halfwave (130) foot dipole.

      HOWEVER there is a problem with feedline loss, so as a practical matter, it’s like women and sailboats – a balancing act.

      My best-over 80 meter DX antenna was up 85 feet at the apex, but the tree was on the edge of a 20 foot ravine, so height about average terrain (HAAT) was about 90-95 feet. With 1 KW SSB from Kirland Wa, a 20-over S9 into Long Branch NZ (was it ZL1LV? time and memory blur).

      Second thing is use a balun because the dc resistance to ground is so low. This also provides for a much quieter antenna overall. (Use a nelson antenna HF choke on your coax, too to take the common mode noise in a city environment.

      Third, in your situation a simple grounding switch on your antenna switch (outside, short heavy wire to ground) would make sense.

      In your situation, I would shoot for 35-feet if you can do a flat top installation, or 40 to 45 feet at the Apex.

      Super antenna here is 50 feet center, 55 feet short side (50 feet) and 90 feet at the high end now. Signal reports to some

      Hope this helps.

      Qro helps, too along withe the Beverages and preseelector lash up

  6. I suppose Chicago is where you need to go to steal your fortune, though I have no idea where you’d fence “super high end” watches. Nobody ever tried to steal my Timex and it’s rarely been off my wrist over the last 10+ years. It still keeps good time and cost about $30.

    BTW, how do you release the line from the drone when/if the line gets snagged on something? Is there a remote hook release or do you have to chop down the tree?

    Happy Rum Sunday(whatever that is). I’ll drink to that.

    BTW, somehow the picture of the scantily clad assistant holding the drink seems to be missing.

    • Drone release answers:
      a. Chop power, gravity does the rest.
      b. Been $500+ on a good Mavic and another $45 on a payload dropper.

      Scantily clad assistant answers:

      a. They tend to run off when it’s 55, windy, and their drink is empty.
      b. You can work on SCA (scantily clad assistants) after dark. High work on antennas?> Not so much.

      Piece and Rum

    • “I suppose Chicago is where you need to go to steal your fortune, though I have no idea where you’d fence “super high end” watches.”

      Go to SanFran to expand your shopping experience…and selling high end watches. That’s easy.. go to DC my friend..
      Put a long trenchcoat, lining the inside with watches and then you can walk up to anyone. Whip open the trenchcoat and say in your most convincing brandon or HB voice…..wanna buy a watch little girl, you smell like your 18 or boy. or old man etc. Oh man..

    • You fence solid platinum, 108-diamond, serial-numbered Rolex and Cartier watches to people on the street who don’t care how hot something is, like drug dealers, and you sell the watches for a couple thou each.

      When the diamond & gold Rolex Oyster was $6500, I could buy either a good counterfeit, or a hot real one, for $200.

      I kept my Seiko…

  7. Amazing, George. We’re mirroring your day here on the W coast; my bride and I are set to enjoy a fine pork butt roast I found for only 99 c a lb and only one teeny-weenie bone! To set the proper mood, we’re pouring those shots of Bacardi spiced Cuba rum into snifters of Egg Nog! And the woo-woo of it all is, we decided to do all this BEFORE reading today’s column!!!
    You and Elaine have an amazing Sunday!

    • That’d be my dinner if you were consuming Myers’s rum. Daughter gave me the pork yesterday and insisted I fix it today…

    • It appears they have ‘discovered’ a ‘sound photon’. Radio waves propagate thru space as photons of RF, also. Electromagnetic waves do not propagate in space… only in the conductors of an antenna. From my readings of the ferrite spin-field antenna. Anyway, spin and orientation are characteristics of a photon that can be measured and detected.

    • “Was it Andy saying Jan. 2022?”

      Now that you mention it Hank.. I think he did say Jan 2022..

  10. “Elaine and I will be doing rum shots”

    Speaking about shots lol..one of the bottles of wild grape wine started to ferment again.. the granddaughters fiancee called said he thought a shot gun went off in his kitchen lol… so a busy day today .. out comes the sous vide.. it’s time to heat it to 140 for 20 minutes to kill the yeast once and for all..

    • I haven’t a clue what the alcohol content of that wine is..I had two small cups and the bed was spinning.. goes down smooth with a kick like a mule.wickedly strong but mellow. woke up with a hangover.. that hadn’t happened since the early eighties..

  11. Big portal day.

    12/12/21. ~ Create Health, Vitality, Prosperity, Joy, Love and Connection, a spirit of fellowship, Brotherhood and Sisterhood all accross humanity and our planet. ~

    DUDE, please help humanity overcome their difficulties, that victory over them may demonstrate to all those who witness it, of THY Love, of THY Power and of THY way of life. So be it.

    Down at the beach with my book, a good cup of coffee, listing to Christmas music and savoring all that life offers someone like me who was fortunate to be saved by Amazing Grace.

    I’m living proof THE DUDE is good.

    As are many. I’m so humbled to be among those so fortunate.

    So to you I speak, as I did to one of my favorite brothers in life.

    Cowboy up!

  12. P.S. for Lenard D.

    Build a bridge and get over it buddy.

    And once your on the other side? Let your bridge stand as a testimony, and Many others will travel it and finding the freedom they desperately hope for.

    When the path of the world everyone is traveling is certain destruction? Create a different path and others are sure to follow.

    There has been enough destruction in the world. Dontcha think? Let’s do something constructive for a while. The soil has been tilled. Seed has been planted, in due season humanity shall reap a bumper crop of joy. A labor of love.

    I am Blessed and Highly Fortunate! It is my hope you are as well.

    Cue: ~ It’s beginning to look alot like Christmas ~

    https://youtu.be/z3vMisNaqd8

    Bing Crosby

  13. Ya know George, the beauty of having powerful enemies is the display of THE DUDES strength and powert to over come them through a nobody like me. Try as one might, you can not defeat the author of Creation. For everyone, even the powerful Angels who are present only know what The Author of Creation reveals to them about this creation. And this creation isn’t all there is.

    I am to be presented with obstacles and difficult choices soon. And when I spoke to THE DUDE about it. You know what HE said? I got you right where I want you. Let see what they can do, so I can witness their intentions and when I know them through and through, I will deliver them under you. I said why bother with a fella like me? I’m just Andy. Not really that big of deal. HE said, why not you? I said get on with it then. HE said, that is what I love about you.

    As surely THE DUDE has given me victory over the paw of the Lion and the Bear, so will HE too, give me victory over myself and my enemies.

    As it is written, so shall it be.

    Have a merry merry Christmas! To the World, a savior is born.

    I have been presented now with two options to leave Seattle. One to go to Alaksa permanently. Both offer beautiful woman and more money. Two doors unlocked. Let’s see what the 4th door is before I decide.

    Later, yo!

  14. I have Citizen and Seiko solar watches sitting near a window, all still keeping time. The watch I wear day-to-day is a Swiss movement titanium-case Bertucci with an aftermarket Maratac wristband. It requires a new battery periodically, but otherwise, it just keeps the time. I might have paid $75 for the watch on sale, and another $10 or so for the band. Kids think it is an expensive watch. So far none have tried to roll me for it.

  15. Yo Jorge, might it be possible that omicron could be the end of the plandemic?Is it the Joker in the deck that the powers that were never saw coming? Will this bring the discussion of herd immunity back to the forefront? See :
    https://alexberenson.substack.com/p/urgent-stunning-data-from-south-africa/comments?token=eyJ1c2VyX2lkIjoxMjUzNTE2OSwicG9zdF9pZCI6NDUzNDMzNTksIl8iOiJUV290TiIsImlhdCI6MTYzOTI5MzQxOCwiZXhwIjoxNjM5Mjk3MDE4LCJpc3MiOiJwdWItMzYzMDgwIiwic3ViIjoicG9zdC1yZWFjdGlvbiJ9.7uRpMKYGTUEF1rIzcrDpqwe5t3bWU3Yp5VIr3dWJ2Fs

  16. I understand the matching issues between 40 feet and 75 feet but what happens if you hang the antenna lower. Do you get a Nvis effect? or can you do a semi inverted V from the feed point?

    • Yikes. Depends on the antenna design, HAAT, frequency and so forth.
      You can download the free demo program from https://www.eznec.com/demoinfo.htm and model up to 20-segments.

      Roy Lewallen is retiring from EZNEC and so after first of the year even the grown up version of the program will be available – free. So remember eznec.com

      As to the NVIS (going from memory early on a Monday) as I recall the effect becomes more pronounced the closer you get to the ground.

      Let’s say you have a 40-meter antenna – a simple dipole at some height.

      The best” height would be one wavelength above ground Since a half wavelenght is about 66.8 feet aty 7 MHZ, the BEST antenna performance would be about 100-feet up. The ground is not perfect, but say 130 feet over metal ground.

      As the antenna comes down, even a half wave up 66.8 feet, the take-off angle will still be good. 30 degrees

      Now, as we continue lowering it toward ground, the two lobes out to the horizon than were perhaps 30 degrees above horizon at 60 feet, begin to climb. As you get down to a lower elevation, the take-off angles rises. atr 40-feet up, the take off is at 50%, for example. Which is fine for state-side comms.

      As we lower the antenna, we see the angle rise:

      At 30-feet, the take off angle (remember, this is a 40-meter dipole – two wires 33.8 feet, fed in the middle and not an inverted v – will be effectively 90 degrees.

      Nothing wrong with a 30-foot high antenna on 50 meters (7 mhz) but the application will be for regional (daytime, NVIS – near vertical incident skywave – propagation.

      From this, we can infer a kind of “good day” and “good night” elevation for each band.

      A good day height on 20 meters (lots of daytime skip) would be a minimum of 45 feet at the center. This will give you a take-off of 20-degrees which will make Europe, no sweat.

      At 7 MHz, the same take-off angle rises to 50%

      And at 3.5 MHz, low end of 80 meters, you are essentially at a 90 degree (NVIS range).

      Which is why on 80 meters, I like a minimum of 70 feet of antenna height because the takeoff angle is 65% and now you can work at least some DX – distant contacts. My all-time best 90 effective foot antenna for 3.8 MHz was a take-off angle of about 40-degrees.

      That antenna kicked as at night, but sucked during the day. A 40-foot high antenna was idea for the early evening contants.
      \Hope this helps

      30-feet

  18. Manic depressive Mossad plant . Always figure it out . Throw piss and meat down your diabetic temple

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