* Turkey Weekend Antenna Project
This weekend, rather than do the traditional S.S.T. Sandwich (also known as a Hot Brown) we instead head into the outdoors to field test a new antenna design I came up with a while back. It’s not as boring as it may sound. I will keep it simple, too, so everyone will be able to follow along.
Basic OCFD Antenna Theory
OCFD simply means an Off-Center Fed Dipole. A “regular” dipole is generally a 1/2-wavelength wire, split in two at the middle. Usually fed with conventional 50-ohm coaxial cable. This is cable with a wire in the middle, a layer of insulation around that. Then an over-layer of metal braid, and finally topped off with some good insulation.
A “normal” dipole works very well. In fact, it’s the standard against which other antennas are measured. When we consider antennas, we can predict gain (or -loss) in “pure modeling space” in which case the measurement is called out in “dBi” – decibels isotropic. The more useful measurement is against a dipole which is 2.15 dB less than isotropic. Thus, these measurements are called “dBd” (decibels relative to a dipole) or (in the modeling program EZNEC (now free on the net) “dBref.” Which allows you to directly compare things like beam (directional) antennas.
Significantly, antenna manufacturers stretch the truth about antenna gain, most of the time. Believe me when I tell you, there is no magic involved in any of the discussion here today. You can “pile up a stronger signal” in one direction, but since there’s not been an over-Unity antenna built yet, the gain one way is offset by a loss in another direction.
This, in turn gets us to something called “take-off angle.” When you want to work DX (the radio op’s abbreviation for “[long] distance” (“skip” if you are a CB’er) take-off angle control is vital.
In the daytime on low bands (like the 3.8 MHz 75-meter ham voice band) you want as much energy as p0ssible to go straight up. This is called “NVIS” near vertical incident skywave and results in great close-in to regional coverage.
But when “bands are open” you want to squirt the signal down toward the horizon as much as possible.
The simplest low-angle antenna is the 1/4 wavelength vertical. Which on the 75-meter band would be one-quarter of 75-meters (approximately) in length. Call it 18.75 meters, or about 61 or 62 feet. The lower the frequency goes, the longer antennas become. Which is why AM broadcast towers can be hundreds of feet high. While 100 MHz-range FM antennas are only a couple of feet long.
Vertical antennas have their issues, though. Noise, for example, tends to be vertically polarized. They are noisy. And they require a significant gfround system to work well. Dipoles and variants are quieter.
The formula is 468 divided by the frequency in Mhz. For an FM station, 100 MHz, a full wavelength is 4.68 feet, so the quarter wave is 25% of that…1.2 feet very roughly.
Feeding Antennas
Receiving antennas are normally subcritical. In other words, any convenient length of wire can be made to work passably. It may not have gain, but it’s not critical.
Transmitting, though, changes this. You want to “match impedances” from your transmitter out to (and including) your antenna. Thinking of impedance like a “garden hose diameter” is useful. If you have everything “matched” to a 50-ohm impedance coaxial line, energy transfers will be highly efficient. In fact, Ideally, your antenna would present 50-ohms to your “antenna hose”.
This problem of antenna feeding is universal. While the “regular” off-center fed dipole, for example, has “resonances” somewhat close to 50-ohms, as we see in the following chart, there’s a lot of “mismatch” which is reported as Standing wave ratios. As a general rule, antennas need to be matched well-enough that a 50-ohm coaxial cable will be “looking into” not more than double its characteristic impedance. A 50 ohm feedline connected to a 100 ohm antenna will have what’s termed a 2-to-1 Standing Wave Ratio (SWR for short).
Here’s the thing, though: As the SWR rises above that 2:1 level, power losses accrue very quickly in nonlinear fashion.
There are strategies to reduce (nearly eliminate) the SWR. This can be done with broadband transformers (called Baluns for balanced to un-balanced or by Ununs which transform the impedance unbalanced to unbalanced which is what an off-center fed dipole presents.
Traditional OCFD antennas are workable, but as we look at their performance as simple wire models, they are far from great.
As you can see above, the antenna is OK – but only just – at the 80-meter ham band.
Not being a fan of lossy baluns and ununs, it occurred to me that if I were to capacitively feed the (long side) of an OCFD, two things could be achieved.
- The resonance points on 80 meters, which fell outside the ham bands on the low end by a smidgeon, could be raised into the phone band.
- And the impedance on the 40-meter band could be brought down to something very useable.
After a bit of modeling, including putting a 160 picofarad capacitor in series with the wire on the long side, something approaching magic started to appear.
These were not just workable; they were really damn good.
The Take-off Angles
Here again, this small modification looked like a winner. On the 80-meter band, a lot of energy went up (to become NVIS):
And on the 20-meter band, performance promised (in certain directions) to give the broken beam on the top of my tower a run for the money.
In recent weeks, a vague plan had come into view.
I’d build the antenna using a bit longer than a 6-foot length of coaxial cable. By feeding the center conductor on one end, attaching the outer conductor to the long side of the antenna (making sure the center and outer braid didn’t touch anywhere, and in fact are well-insulated) I would have created a “linear capacitor” of about 180 pF (picofarads) because RG-213 coax presents about 30/pF per foot of capacitance.
Into the Toy Dept.
First thing you need is a plan. Ours went like this:
- Design cool antenna
- Attach super strong fishing leader to drone
- Fly over highest trees
- Backhaul 700 lb paracord
Since I already had the drone line reel and drill ready:
…all that would be needed is an attach point on the drone.
For this, a single wire wrap would suffice.
Then it was a simple matter to launch the drone over a 90-foot class tree:

With one tree done, the other two supports turned into time sinks.
On the line over the boom of the beam antenna, three or four outings on that one. Got over a trap on the antenna on one attempt. Next the drone tried to
“suicide out” on us by wrapping the tiny fishing line around a prop. Screwdriver, repair was easy, but all the while burning daylight.
Eventually, all worked out.
Well, almost. Here’s one of several “mid-air incidents” snipped from a 90-foot tumbling
fall from the top of a southern pine…
One thing we learned was not to do this with wind coming up. When the line is out too far, the wind will move it into places you really didn’t want to go. (Did it really take a JD/CPA and an MBA, both pilots, both extra class hams to figure this out? Well, um…)
One other thing to build up ahead of time (I keep it around because it’s so useful for antenna projects) is a wire dispenser.
Couple of “A” frames, couple of spacers and a hunk of rebar to hold the roll of whatever you’re flying that day.
A dandy way to spend a good chunk of the day. My consigliere kept running off every half-hour, or so, to hear Ohio State losing its ass. (I could care)
We knocked off about 3 PM when we got all the antenna halyards in their assigned locations. Today, antenna construction and we should get it on the air this afternoon, sometime.
Next week, we’ll confess how it works (fingers are crossed). Theory says it should rock, but you never know until you test drive it a bit.
The prime rib following was cooked to perfection, but not as tender as usual. No telling what happened there.
With no leftovers leftover, tonight we’re doing a pizza and some vino. This antenna adventure really burns off the calories when it’s cool out.
No humans were injured in the mounting of these antenna halyards.
Write when you get rich – performance reports as they happen.
George@Ure.net ac7x\
Italian Grandma makes pizza and pizza sauce.
Interesting two step process regarding the cheese, Pecorino Romano and mozzarella.
https://youtu.be/OjXWVSbWBV4?si=TMnmFDObXgsGVcOa
TWAP ? Wait what ?! what what what.
ohhh THAT WAP!
Black Sunday..Hoes in da house – https://www.youtube.com/watch?v=XRpt2tb2y5U&pp=ygUSdGhhdCB3ZXQgYXNzIHB1c3N5
Am I that old that the above seems nasty and the over the top, on disgusting side of things ?
* Oh well color me old school then..
Too harsh and angry for my taste. I have no problem with female flesh, but there has to be softness and kindness to go with it. There seemed to be none of that in the video. Mellow the rhythm and replace the track with something like “Never My Love”, from The Association, and it would be much more appealing.
I am slow today,
What are you dropping over tree, line with a weight that reaches the ground so you can grab it and manually pull the heavy line up to the tree?
The tree end of the paracord is anchord at ground level with the spring?
The paracord will be rubbing over a tree limb?
How do you release the line from the drone over the tree?
Sorry if I missed something
1. Tie line to drone with zip tie
2. Fly over tree pulling fishing line.
3. Fly a tree length, or so, away from the tree
4. Return on a 45 degree descent.
5. When drone crashes, find it.
6. Tie paracord to the recovered end of damn near invisible fishing line.
7. Have cohort turn on electric drill with fishing line.
8. As the fishing line is wound on drill, it backhauls the paracord.
We will get arty about the tree tie offs later. If immediate concern, we keep a half dozen of these on hand. Secure the pulleys so there’s no rope friction on tree. https://amzn.to/3Gdun0B
Put 5-10 lbs of weight at the bottom of the line from antenna, after going through pulley, down to weight.
Tnx.
Sorry about duplicate question.
…not to compete with Fearless Leader, but for reference here is KW1B’s drone-free low-tech method.
1. Get a decent (safe) slingshot. (Use eyewear!)
2. Get a 1-oz ball fishing weight. These usually
have a hole drilled through the diameter.
3. Fishing pole with “casting” reel. (The kind
where the outgoing line spills freely off the
end of the pole’s spool. Use 15 pound line.
4. Tie the line to the weight.
5. Shoot the weight over the tree or branch
you want. (NOTE: There is considerable
“flight time.” Apply “brakes’ by hand, to
the line, limiting its flight, and dropping
it on the far side. It should fall easily to
earth, right where you want it. Admittedly,
this takes some luck and skill, and might
need more than one shot to do the deed.
Now, the REASON for the fishing pole at
all will become evident if you make a bad
Shot. You can easily wind back and retrieve
ALL the line AND the weight, by “playing”
the line with the pole. Recovery is well
over 95%, so little line is consumed. I’ve
shot four trees in recent months, and I’m still
on the SAME wight and line. I made maybe
nine or ten shots to succeed with four trees.
6. Once you’ve located the weight and line,
BACK HAUL a light string over the branch
using the fishing pole. Detach the line.
Using the string, HAUL your heavy line back
to the landing zone. (NOTE: By now, you’ve
recovered ALL the fishing line and weight.)
7. I use a pulley system with a twenty-pound
sash weight to counterweight the antenna,
and allow for considerable tree wind sway.
100% of the tension in the antenna comes
from the window sash weight.
Notes: A 1-oz ball weight is about perfect. Its
got good “Carry-Mass,” and is easily wound
back for a miss, or with the string. Teardrop
weights can snag on retract. Arrows are
hopeless snaggers. White string will let you
see your path for a possible re-shoot. Some
‘ use a potato gun for this, but I find the line
often cuts the potato, or the potato just
fragments on launch. Unreliable.
Be sure to allow for the line’s spill-out at
high-speed launch. Tangling is easy, so
plan your moves with smarts and care.
Many enhancements are possible. I paint
the ball weight with Hi-Viz bright orange
paint. Easier to track and find.
Good shooting!
– 73 –
For those mainly iterested in casual listening, only, for such as AM Broadcast band DX, or SWL, or other general purpose listening, a “random-length” end-fed plain single wire at the window, stretched out to a tree will be fine. 30 feet or a bit more will do fine. Super-long — over 100 feet — will do nothing extra useful for you. “K.I.S.S.” is good. (I use black, insulated wire for reduced visibility anti-HOA reasons. But bare wire is fine. Damn near ANYthing is fine. Slant-wise is fine. Just get it up high enough to not choke passing deer or humans.)
For efficient TRANSMITTING, antennas suddenly become Very Importnat to be made extremely well,
as The Boss has illuminated.
Good and useful intel at long ranges (a few hundred miles or so) can be easily had with a simple random-length wire. (This comment meant to encourge beginners that “simple is good” for initial purposes.)
If your roof has intersecting ridges and is big enough, running a wire insulated from the roof from above the peak of one gable to above the next one(on the intersecting ridge) would make sense. It’s simply a wire above or beyond the valley of a roof, unlikely to be noticed by nosey neighbors. Extra points if you have a metal roof that’s properly grounded. I’m no expert on antennas – they are black art to us digital types, but it seems to me that it would work best if normal to the direction of the station(s) that you prefer to receive.
https://www.gospanews.net/en/2023/11/17/us-president-biden-sued-for-complicity-in-israels-genocide-in-gaza/
as it all comes out that intelligence reports were passed on to everyone about that surprise attack.. and the continued attacks even tjough the criminal elements were taken care of.. they might just win.. now if they do who pays.. Biden or the guys at the fast food shops..
how many war fronts are we at now..five or six..
todays around the ranch reads like the Hierophant, right side up.
success.
hmmmm interesting.
“Next week, we’ll confess how it works (fingers are crossed). Theory says it should rock, but you never know until you test drive it a bit.”
wishes on occasion due come true.
time for a change…..
you know on 11/11 i was on the coast of oregon. sea side. listing to the ocean speak in waves.
like you listing to ure antenna in waves.
i drove there for the day and back the next. oregon is so beautiful in the fall. the golden and red leaves falling off the trees. so soo so beautiful.
i woke up after being sick as hell from pnumonia, half awake and half asleep i had a vision of a 9.5 earthquake there and a giant tusnami the next day.
so i drove down there. when i got there i entered this place and above the threshold of the entry it read, “expect a miracle”.
and there i was.
sooooo…
i went and stood on the beach. and no earth quake or tsunami happened.
i thought if only King Canute could see me now and laughed.
it was a beautiful moment in my life.
see ya!
there was a 97.82 % chance i could have won the powerball jackpot that day, with a ticket i bought in jackson hole, wyoming had i not gone to sea side oreagon.
but the choice was obvious.
not many who have visions of great earthquakes and tsunamis will run to stand where it happens, knowing that The Maker of all things, ~ THE DUDE ~ will not let any harm come to them. and in doing so, no harm would come to anyone else.
faith, ya know?
what i gave up to stand there in the gap, will come to me another way.
with that,
que ~ waves ~
https://youtu.be/6vVa6jiDQF8?si=9XyHs1rz5A0YXcvU
Andy, with your permission I would like to share your comment here with a young priest I know who always has to refer to direct word for word quotes from the Bible when explaining Faith.
Very well said.
i do not own wisdom. you need not my permission to relay it. it freely given. i am only its humble servant.
im in buisness with God. HE is my employer. I invest in His Kingdom and He pays me handsomely.
have a wonderful day.
:)
much love
My first skim of your adventure before church was quick but about mid Homily this morning it hit me. “Is he talking about a trombone capacitor?”. Back at home having breakfast and looking at a couple websites with cylindrical/coaxial calculators I need a couple aspirin after math on Sunday before digging into this deeper. Then I was reminded quite loudly that the dining table was for eating and paying attention to my lovely spouse. But it is bona fide scientific research I said. Sets her fork down with an Icy stare. Yes Dear.
I do have one question. Why the selection of RG 213 for the capacitor? Mathematical, ease of use?
Also I am curious from your AAR. Hopefully there wasn’t any serious damage done to your aircraft after the mentioned mid air incidents. Certainly sounded like a fun time was had by all.
Snow at the ranch overnight. Found Coyote tracks around the goat pens leading to signs of a struggle this morning. All the stock and dogs are accounted for. Bert and Ernie seem a little stirred up and keep looking towards the trees across the pasture. We’ll go check that out later this afternoon.
Stay safe. 73
rg-213 has one of the higher center conductor insulation values 5 kv, and some rg8 is only 4. Which with 1.3 kw out seemed like cheap fire insurance.
As to the crashes>? I can tell you with high accuracy that the right front gear leg and motor asy is going for $39.99 on Amazon.
Pilots with as many hours as me have learned to talk ONLY of good landings. Except for a brake lock-up which sent me onto the grass along the runway at KTIW, never even had any scary moments flying. I don’t fly drones over people even though licensed. My consigliere will be transitioning to commercial drone ticket one of these days – it’s easy if you hold a valid ASEL which we both do.
However!!!
My consigliere and I are arguing even now over whether (his view) the added weight of the tie wrap put my drone over legal weight limit for drone. After I asked how much does electricity weight (lol) I explained that with a line on it, the fishing line, see, it’s no longer a uav and is thence a wire tethered device and not really a drone. Lest the FAA start regulating wire controlled aircraft that go in circles? This may not be resolved until scotch time this PM.
Desktop AI offers a split decision:
According to the FAA, a tethered electric airplane is not considered a balloon or a kite, and is subject to the same rules and regulations as any other unmanned aircraft system (UAS) 1. This means that you need to register your tethered electric airplane with the FAA, follow the operational rules for UAS, and obtain a remote pilot certificate if you want to fly it for commercial purposes 2. However, there is an exception for tethered aircraft that are operated by a community-based organization (CBO) or as part of an educational program. In that case, Congress has directed that such tethered aircraft can be operated without a pilot certificate, waiver, or other approval by the FAA 3.
He will predictably argue it was a commercial flight because I was installing an antenna for an article and pictures from aloft were used and there are Google ads on my site. I would argue ShopTalk Sunday is an education program and thus, exempt.
Yeah…it’s like that out here in the trees. Elaine just rolls her eyes…
Meanwhile, I’ve pinged Amazon to order me some negative-weight tie wraps out of China just to color inside the lines. They’re made of UFO debris and can return to their own shape (and planet) when left unattended.
Copy that.
While Ure at it get Ureself on the list for the latest cloaking tech. Think of the fun and frivolity you can have then. Just be careful you don’t crash and then can’t find your aircraft.
What’s that old saw…? Never argue with a lawyer…?
Must have been a helluva holiday dinner when even the drone puts on weight! :-)
as i was leaving the beach that day George, on 11/11/23 after standing where the giant earthquake and tsunami was to happen in my vision while half awake and half asleep, and saying, The Lord thy God is wirh me! He keepeth me safe and everyone and everything around me.”
the waves washed past my feet and moved the sand uncovering a green spoon infront of my feet.
and i smiled.
here is a picture of it,
https://twitter.com/ore_train_11/status/1728822832950579656?t=-Blrw46Czw5G1Y2QeR9rzA&s=19
and instanlty, i wasnt sicj any more.
see oxfords definition of green spoon effect,
https://www.oxfordreference.com/display/10.1093/acref/9780199657681.001.0001/acref-9780199657681-e-3609
“n.
Greenspoon effect n.
Modification of the content of conversational speech, without the speaker’s awareness, through *reinforcement given by the listener in the form of nods, smiles, or expressions of approval such as ‘mmm-hmm’. Such reinforcers have been used to increase the speaker’s use of a certain word, or a category of words such as plural nouns, or the frequency with which the speaker expresses personal opinions, and so on.”
so ya know, when im not around here on urban survival much in the comment section. well im doing the Lords work.
best get busy being about it.
Did you drop a weighted line to the ground on thr far side of the tree?
Is the spring at ground level?
Does the paracord rub over a limb?
USAF fighter jet refueling from an airliner wing boom!
Question? was this AirForce One or Trump Force One?
https://x.com/DanScavino/status/1728618068002165160?s=20
If it is Trump’s plane, why the USAF escort? hummmm
Not a civilian airliner at all. The young lady in the video is wearing desert camo uniform. Also note the viewing position is just behind the wing, and there’s a bulkhead blocking travel aft from that point. I’m guessing it’s a USAF tanker set up to feed 3 at a time.
good eye there, oldfart, thanks
while i was at my spot today, talking to THE DUDE, you and ure readers a very very nice HX 50 luxioury helocopter flew over me.
right over me and stopped for a moment loooking down at me.
never seen one of them in real life and ive never seen one out there at my spot flying.
i waved out the window and said Hi.
friend of Ures?
lol
got someones attention.
:)
“got someones attention.”
Probably Satan!
G.A. STEWART: I do believe that the character in the chambray shirt and denim jeans seems to have been my second meeting with Satan.
He certainly was not as haughty as he was in the 1994 dream. This time, he looked like he had gone more than fifteen-rounds; I was the one standing over him in the finest suit that I had ever worn and telling him that “God loves him.”
https://theageofdesolation.com/nostradamus/2023/11/26/the-devil-came-down/
oh. a man was drowning and said God save me!
then a boat showed up and said get in. and he waved them off saying no thanks, God will save.
then a ship shows up. they said get in. he said no thanks, God will save me.
then a helocopter shows up and sends down a line. he waves them off says, God will save me.
the man dies and stands before God and says, Why didnt you save me?
God says, Did ya get the Boat, The Ship and The Helicopter i sent ya?
well, it seems God is sending me a Very Nice Helicopter.
i will get in that bitch right now. lets go to rio de jenera and hang out with some brazillian chicks in thongs.
hahaha
seems like a damn better plan to me, stan!
Andy,
It’s never too late to download the chopper pilot dream wars program. Trinity doesn’t have to do all the work.
Let’s follow the white rabbit ears and join everyone’s favorite mouseketeer, DJ George, for some post-holiday sine-curve cheer on your am dial:
“Carrie Anne”
The Hollies
Cool and windy today. Pecan trees are transitioning from bright yellow to bare. Started making my own transition to winter living. I swapped out a trunkload of long-sleeve shirts in storage for summer weight shirts now out of season. Pulled the midweight coats out of storage, and made a mental note as to where the heavy coats were hidden. I am expecting seasonably cool weather through December, with the transition to below normal temperatures after New Years. The grid reliability was good last year, but we will see if complacency has returned.
3 degrees F on The Mountain this morning. i saw three big lights in the sky shaped like a triangle. really bright abovr the peak.
i tried to get a picture but they vannished before
cowboy up!
im so ready for some place warm and sunny.
pray for me. haha. im getting to old for this shit. hahaha
You might actually benefit from some of Jerry’s Antarctic leftover stock in February. You have to call to see what what sizes and colors are left.
https://www.wiggys.com/wiggys-blog/sale/
https://halturnerradioshow.com/index.php/en/news-page/world/proof-dtcc-did-delete-ubs-bond-cusip-number-s
got a message today from an old friend and professor.
is the international banking system finally starting to give way…
George,
You talk a lot about dreams, so check out Stu’s “dream” at The Age of Desolation site.
Very intense.