Dream Antenna

[AB2EZ]

Every antenna couples power into both radiating electromagnetic modes (which comprise the far field) and non-radiating modes that decay exponentially with distance from the antenna (which contribute a portion of the near field).

For a given amount of total power that leaves the antenna, an electrically short antenna has a larger ratio of near field to far field. The larger near field is dominated by non-radiating electromagnetic modes that decay exponentially with distance from the antenna.

The near field produces heating losses (e.g. ground losses) in the vicinity of the antenna.

Even if the antenna's conductors, the feedline, and the tuner have zero losses, the larger near field to far field ratio of an electrically short antenna will limit its radiation efficiency compared to a full size antenna.

Sometimes nearby conductors couple to the antenna, and become part of the antenna (just as the parasitic elements of a yagi are part of the yagi).

The shorter a dipole antenna is, compared to full length, the larger the near field amplitude will be.... and the larger the fraction of the total RF power that will end up heating the ground and other nearby objects.

Stu

[ka7niq]

I think the idea behind Frank's antenna is to minimize feedline losses by using homebrew very heavy gauge openwire feedline and a tuner using 3/8" copper tubing and strapping connections throughout.

A dream version of his antenna would be to have the amplifier mounted up at the center of the antenna and the final pi-network directly coupled to his low impedance antenna. In this case, I bet his short dipole would be within two dB of a full size dipole on 75M.  

And, if the antenna conductors themselves were on sufficient diameter, there would be no loss compared to a full size dipole.  So if we can minimize the tuner/feedline losses thru heavy conductors, we are almost there.

Theoretically, we could use a 75M dipole that is only one foot long made of superconductors that exhibits close to zero ohms. This would work as well as a full size dipole. Just imagine a 3el 75M Yagi that you could hold in your hand.  The radiation pattern would look the same as a full size antenna.

Bottom line is it's all about how much we control the losses when we shrink down antennas below full size.  Since superconductors are not yet practical, brute conductor thickness is what we have to work with.


T

Yes, that would be nice, to have the amplifier mounted at the feedpoint.
I used to own a Henry 3K Ultra, I think it was?
It had a remote controlled RF Deck. The idea was to place the amp right at the base of the antenna, and control it from the shack.
It only had a single 3CX 1200 tube in it, but it was an "export model".
I traded/sold it to W0AD, some years back.

[K1JJ]

Stu,

What if a severely shortened, loss-less antenna is in free space or on an infinitely tall tower... does all of the near field power eventually get radiated?

T

[AB2EZ]

Tom

If the surroundings are lossless, then energy is stored in the non-radiating modes, but it is not converted to heat, and not radiated... analogous to an ideal capacitive load across an AC voltage source. Therefore, all of the power that leaves the transmitter is radiated (nothing is lost in the wires, the transmission line, the tuner, or surrounding objects).

In practice, the shorter the length of the antenna is compared to full length, the more difficult it becomes to avoid resistive losses due to currents induced in surrounding objects, and hysteresis losses as well.

Stu

[W2VW]

After many tries to minimize coupler/feedline/radiator losses and some on the air comparisons I conclude the following.

Given giant stupid size inductors vacuum variables #8 feeders and #8 near doublet center tapering toward ends to #10 to save weight.

120' antenna center @ 80 feet ends 60'

160 meter signal reports were generally down 6 dB in guess meter strength compared to a friend 15 miles away with a full sized 160 horizontal radiator at 110 feet.

Really not bad.

I know 3 operators in this general area who put a good amount of time on 160 in the last 10 years with shortened doublets, 75 meter size and less. Bill Russel, The Slab Bacon and myself.

This is not for anyone who is not willing to build a coupler. Even BC-939 coils got hot at QRO. Try that with a high pass T into a 4:1 BalUn and the SWR may be good but not much will go out the pipe. 

The very same setup supported only at the very ends at about 33' average height still worked but it took legal limit to make a Ranger sized signal.

Here in New Jersey (Jersey is a place in England) 160 AM operation is much different from what's found out West. Cloud burner antenna work fine. Some of the guys with vertrickles can reach out and touch people further away but are usually down in signal level from others close in. The vert antenna really shine close in during the daylight hours though.

This is not a 160 DX operation requiring the best low angle stuff just to have fun. I have worked across the pond on ssb with the 33' high 75 meter doublet on 160 fone. THAT just proves the patience of some 160 DX hounds. It took about 10 repeats.

I'm noticing many online amateur antenna discussions land up with general "you can't do this or that" based on un-quantified obstacles. Put the antenna together like a race car. Minimize losses anywhere possible. Works. May not work well but it beats being stuck on the internet typing stuff about radio with other guys who aren't on the air.

The shortened antenna can be a way to get on 160 for those of us who don't live on farm sized lots but can have at lease one high antenna support.

The same small lots usually land up being a nightmare for inverted L because the radial field will be incomplete in size and the signal will need to pass right through houses, people, wheelbarrows, dogs, cats and toasters. House wiring lands up being part of the counterpoise also. I've heard many a PW inverted L from small lots. Out West you guys are generally geographically spread out and most likely NEED the low angle antenna just to work more than a couple other AM folks.

K3L 2005 used a 60' center fed doublet. See writeup on this site. See log on this site. Note the 75 meter portion of the log. That outing was put off the air for many hours because of thunderstorms and RFI. Still not bad for a half sized radiator. Stu is right on the money concerning the intensity of near field radiation. Expect extra debugging of interference prone consumer junk electronics.

I'd rather get on 160 with a loaded lawn chair and learn something than sit at the old compuker writing the whole idea off due to software pushed to limits with incomplete/inaccurate input.

[Steve - K4HX]

Nailed it, Dave.

When all is said and done, usually more is said than done.

I did some sims on Frank's antenna back in 2007.

In the sim of the AHE antenna, at 3.8 MHz, the feedpoint impedance is Real(Z) = 11.3874, Imag(Z)  = -305.197. Using W9CF's feedline calculator, at the end of 70 feet of 450 Ohm Window line (this is my guess on the length in use at AHE radio) the Z is 107.34 +j1124.1. Loss in the feedline is 2.76 dB. The 107 Ohms resistive isn't bad, but there sure is a ton of inductive reactance for the tuner to deal with!

So, from the antenna plot, we see that the AHE antenna is down about 1 dB compared to a dipole, when there is NO feed line loss. A dipole cut for 3.8 MHz and fed with 70 feet of RG8 would have feedline loss of 0.27 dB. Adding in the 2.76 dB of feedline loss to the AHE system, it would appear the Frank's antenna is about 3.5 dB down from a dipole. This doesn't include tuner loss. Who knows what the loss in Frank's tuner is. Can't be much based on his signal. But for giggles, lets do some simulations.

Using W9CF's tuner simulator and plugging in the Z numbers calculated at the end of 70 feet of feedline, tuner loss is only 0.3 dB. This simulator is set up for a typical T-type tuner with two series caps and a shunt coil. The simulator finds the lowest loss setting of the components for minimum SWR. In the simulation above, the caps had a Q of 2000 and the coil a Q of 100. There's likely a little more loss in the balun. But looking at the size of the one Frank made, it's probably small. So, worst case, Frank's antenna is about 4 dB down from a dipole. Not bad considering the size!

I've always thought Frank's set up was within 3dB or so of a full sized dipole. The cool thing is, according to the transmission line sim, almost 2dB could be gained by using 600 Ohm open wire line!

Tom, KLR did some sims later and got different numbers, more loss IIRC. I never resolved the disparities.

[WD5JKO]

I am still amazed how well the mobiles used to get out on 160m AM with low power. This was the early 70's, in the Detroit metropolitan area. This activity was quite common before 2m FM took over. On 160, in that area, and at that time, the mobiles were on 1806, crystal controlled. These transmitters typically had a 6V6 or a 6AQ5 in the final, and Heising modulated. The AM car radio with a converter was the receiver.

Those guys were running 5-10W DC input, and used a mobile antenna that might have been 2% efficient.  During the day, those guys got out quite well over at least a 30 mile radius.

The base stations were often at 1835, and inverted L antennas were Kings. I recall many times hearing something like, "Go vertical as high as you can, and then go horizontal". A typical L was about 3/8 wave, and fed with a series capacitor to tune out the reactance.

I took that advice after upgrading in 1974 from a Johnny Novice. With 25 watts (input), I did OK. It was all new to me, and any contact was so exciting. One December evening I worked stations coast to coast, and as far south as Texas. I was so excited, stayed up all night...

I found a write up from that time written by my Friend Larry, WB8FGK. It is on his QRZ home page

Jim
Wd5JKO

[K1JJ]

Interesting discussion...     Yep, Slab certainly does well with his shortened antenna and 500 watts. A big gun up here for sure.

Stu,

So, it appears that the shorter from full size an antenna is made, the MORE important its height above ground and isolation from surrounding objects becomes.  This shows why an 1/8 size mobile whip on 75M has so much problem close to the ground when surrounded by other cars, power lines, ground loss, etc.

It also shows why a shorty dipole needs to be up in the clear as much as possible, even more important than a full size one. This is also a reason why some guys get out huge signals with low, but full size dipoles despite being at 30' on 75M.

From what you said it appears that in free space, a radio wave can begin as a point source and still radiate all of its energy. It does not need a large 1/2 wave wire to "guide" it. BUT, when the same point source is brought into the real whirl with houses, ground, etc., the near field starts to couple energy and waste power when low to the ground.


Happy Thanksgiving, everyone!  (a hearty TimTron beeelchhhh to all!)

T

[AB2EZ]

Tom
et al.

Yes... I agree with your statement below except for one small misunderstanding: "It does not need a large 1/2 wave wire to "guide" it."

The current flowing in the short dipole antenna (obviously) only extends for a small fraction of 1/4 wavelength on either side of the feed point. If there are no capacitive hats at the ends, then the current is maximum at the feed point and zero at each end. This spatially confined current does not couple efficiently to radiated electromagnetic modes (the far field), but it does couple efficiently to non-radiated, exponentially decaying modes (which are part of the near field). The efficiency of coupling between a short dipole and the radiated modes (the far field) is approximately 100% x [l/L] x [l/L], where l is the length of one side of the short dipole, and L is 1/4 wavelength. This formula is valid when l/L is less than 1. The coupling efficiency to non radiated modes (i.e. the non-radiated  part of the near field) actually increases as the antenna gets shorter than full length; but that requires a bit of calculus and electromagnetic field theory to prove.

So, for example, if each side of the short dipole is 1/8 wavelength long, the coupling efficiency of the short dipole to the radiated modes (the far field) is approximately: 100% x [(1/8)/(1/4)] x [(1/8)/(1/4)] = 25% of what the coupling would be with a full sized dipole.

The tuner/matching network/load coil  attempts to make up for this by increasing the amplitude of the current that flows out of the feed point by a factor of 2, compared to the feed point current of a full size dipole. [2x the current => 4x the power; 4 x 25% = 100%]

If the losses in surrounding objects (which are exposed to the near field) are low, then you can just increase the feed point current to make up for the weak coupling of the antenna to the far field. But this higher current, and other factors that have to do with the distance the current extends from the feed point on either side of the dipole, increase the amplitude of the near field. Therefore, for a given surroundings, a larger and larger fraction of the total transmitter output power will be converted to heating of the surroundings, instead of being radiated.

For l/L less than 1 (i.e. a short dipole), the increased near field losses may be totally acceptable.

For example, in my new home, I use a dipole on 40m that is only 25 feet long on each side ... i.e. l/L is approximately 25 feet /34 feet = 0.74; and the efficiency with which this antenna couples to the far field is about 100% x 0.74 x 0.74 = 55% of the efficiency with which a full sized dipole would couple to the far field. I use a tuner to make up for the mismatch (i.e. to increase the current flowing into each of the 25 foot long dipole sides at the feed point). Therefore, I have some increased loss in the tuner, in the feeder, and in the 25 foot wires vs. a full length dipole... and the near field of the antenna is larger than it would be with a full length dipole. Overall, the associated losses (vs. a full size dipole), and the RFI  are acceptable... considering that this is a longest antenna I can put up. Also, it is definitely not "in the clear". It actually running across the 2nd floor of my house, at ceiling height. Therefore, the losses associated with the near field are larger than they would be if the antenna were located high up, and in the clear. On 40 meters, the antenna seems to "get out" reasonably well, based on signal strength reports.

If I tried to use this same antenna (a dipole, 25 feet long on each side) on 75 meters, then l/L would be 0.39, and the coupling of the antenna to the far field would be 100% x 0.39 x 0.39 =15.6%. Using a tuner, I could probably push my transmitter's output power into this antenna... but the currents at the feed point would be (roughly) 2.5 x as large as they would be with a full sized dipole, and the near field amplitude (volts/meter) would be higher than with a full sized dipole by a factor of more than 2.5 (because the coupling efficiency to near field modes actually increases as the antenna gets shorter). Of note, this antenna works fairly poorly as a receiving antenna on 75 meters. I can load into it using my tuner (I can obtain a 1:1 SWR on the transmitter side of the tuner)... but I haven't yet tried using it as a transmitting antenna on 75 meters.

Happy Thanksgiving to all!

Stu

Interesting discussion...     Yep, Slab certainly does well with his shortened antenna and 500 watts. A big gun up here for sure.

Stu,

So, it appears that the shorter from full size an antenna is made, the MORE important its height above ground and isolation from surrounding objects becomes.  This shows why an 1/8 size mobile whip on 75M has so much problem close to the ground when surrounded by other cars, power lines, ground loss, etc.

It also shows why a shorty dipole needs to be up in the clear as much as possible, even more important than a full size one. This is also a reason why some guys get out huge signals with low, but full size dipoles despite being at 30' on 75M.

From what you said it appears that in free space, a radio wave can begin as a point source and still radiate all of its energy. It does not need a large 1/2 wave wire to "guide" it. BUT, when the same point source is brought into the real whirl with houses, ground, etc., the near field starts to couple energy and waste power when low to the ground.


Happy Thanksgiving, everyone!  (a hearty TimTron beeelchhhh to all!)

T

[ka7niq]

I think the idea behind Frank's antenna is to minimize feedline losses by using homebrew very heavy gauge openwire feedline and a tuner using 3/8" copper tubing and strapping connections throughout.

Well, that "Bad News" is Frank's Antenna is not doing very well, when subjected to Computer Modeling by some well known, and respected Antenna Guys http://forums.qrz.com/showthread.php?414706-Anyone-Care-To-Model-this-Simple-Antenna/page2

The Good News is that his antenna can very easily be improved!
Instead of doubling the wire back on itself, all he needs to do is to allow the same amount of wire to droop down vertically.

Happy Thanksgiving Everyone!

[K1JJ]

The Good News is that his antenna can very easily be improved!
Instead of doubling the wire back on itself, all he needs to do is to allow the same amount of wire to droop down vertically.

Yes, the "Skirted Dipole," as some call it.

I've always liked the results of hanging the ends down vertically when the flat top is short.  It appears to load the antenna well and pull the current out as desired.

Bob, K1KBW has up a shortened 160M dipole at about 70' high doing the skirted thang. On 75M, he is one of the loudest locals in New England.  On 160M, he does rather well locally too, considering it's only 1/8 wave high on 160M.


Stu, thanks for the info, OM!


T

[Steve - K4HX]

Hope to hear that antenna on the air soon from your station Chris.

[ka7niq]

Hope to hear that antenna on the air soon from your station Chris.

Thanks Steve!
I too am "lot challenged", and that's why Frank's Antenna appealed to me so much.
A 60 ft flat top looked like something I might be able to squeeze in here.

[The Slab Bacon]

When discussing antennas, one has to keep in mind that after WW2 there was tons and tons of surplus coax out there cheap on the surplus market, and the ARRL adopted it's use with open arms. Thus leading to 52 and 75 ohm charactoristic impedance becoming the "world" standard for feedline. With 75 ohm somewhat "falling from grace" as the surplus market started to dry up. Most older forms of balanced line / open wire fed designs then becoming less favorable.

And then you get into the "appliance operator" false myth that open wire radiates. When in reality you have much more feedline radiation problems with coass then you will ever have with parallel feeders. I got to witness this phenomenon first hand well over 20 years ago when Derb used to live at his mothers, and had a run of ladder line (the crappy brown stuff) running right next to a $50 K-Mart B&W TV. It didn't as mich as put a line in the picture!

With that being said, most hams (especially appliance operators) turn their noses up at the thought of balanced line fed antennas. Feeding a dipole (or whatever) is the key to using 1 antenna on multiple bands! One year when we were doing the Farfest special event station at the Howard County fairgrounds, we needed close to 100' more feedline than we had to get from the back of the stable where the antenna was to the operating position. So we made "ladder line on the fly" We stapled 2 100' runs of #12 THHN to the wooden pillars that supported the roof of the building. Several appliance operators laughed at us and swore that it would never work. We kicked ass and took names that weekend on 40 and 75! ! !

Now, in a long previous discussion, Stu (AB2EZ) said "Why would anyone want to use a shortened antenna?" I replied to him "Because some of us don't have a choice!" That was the end of that discussion as he usually tends to take the long way around the block, and I am a big KISS advocate. Keep it as simple as you can. I have about 65' of horizontal run to put whatever I use for an antenna in. A compromised antenna beats the living hell out of no antenna at all! ! ! ! ! ! ! ! !

Now, with all of the above said, Jim (JKO) makes a very good point, the little short mobile antennas that used to be used on 160. Any length of radiator is resonant on any and every frequency, just not at a 50 ohm nominal operating impedance, or perfect radiating efficiency. The tricks to making it work are:

1. Figure a way to make it's charactoristic impedance look appealing to the 
    transmitter. (match)
2. Eliminate as much loss/inefficiency as you possibly can.
3. Eliminate as much of I/R losses in the feeders as you pussibly can.
4. If you are one of those who can't sleep at night unless you are running 
    coass. And you are insistant on running it in a high SWR application, always
    sin in the direction of too low of an impedance! ! ! In a low impedance
    situation (say 10 or 20 Ohms) The only losses are the I/R losses and most
    likely they will be neglible it you are any good at installing connectors.

    But if you decide to use it in a high impedance situation, you are screwed,
    blued and tatooed! ! Keeping in mind that coass is a big capacitor and the
    interconductor capacitance is pretty high the capacitive reactance will eat
    your RF for lunch! ! Your transmitter output will be pissed away heating up
    the coass, leaving very little left for the antenna!

The idea of a 60' flat top with 30' on each end hanging vertically works quite fine, But.......... One must remember that the loose ends are quite hot and somewhere near the max voltage point of the antenns, please take adequate safety precautions. If you have plenty of height, it becomes a non issue.

The thing that I like about my antenna is that all of it is up in the air, out of harms way. I may occasionally offer suggestions based on my lnowledge and a bit of head-scratching conjecture, but I will label them as such. If I tell someone that "this works" it is because I have done it and I know for a fact that it works. I have built a handful of these antennas for other people, and several others have made them themselves, and I know for a fact that it works. Yea, there have been plenty of naysayers, but EVERYONE that is usung one loves them.
Mine has been up for so many years that the UV has just about disintegrated the plastic dog bone insulators! It's pretty much piss-beat. I guess when I get through with my cancer treatments, I'm gonna have to get up off of my ass and build a new one. That one was just an experiment gone right and only originally built for testing, that was many years ago........ If it aint broke, don't fix it

...-.-
10-4, over and out.

The Slab Bacon (Wit da fat meat shakin)

[ka7niq]

The thing that I like about my antenna is that all of it is up in the air, out of harms way. I may occasionally offer suggestions based on my lnowledge and a bit of head-scratching conjecture, but I will label them as such. If I tell someone that "this works" it is because I have done it and I know for a fact that it works. I have built a handful of these antennas for other people, and several others have made them themselves, and I know for a fact that it works. Yea, there have been plenty of naysayers, but EVERYONE that is usung one loves them.
Mine has been up for so many years that the UV has just about disintegrated the plastic dog bone insulators! It's pretty much piss-beat. I guess when I get through with my cancer treatments, I'm gonna have to get up off of my ass and build a new one. That one was just an experiment gone right and only originally built for testing, that was many years ago........ If it aint broke, don't fix it

Speaking of Cancer, I have lost many friends to that chit.
One ex Marine hard ass (who hated recreational drugs) was so sick from the Chemo and Radiation, he was about ready to give up.
I begged his wife to ration out AND HIDE his pain Meds, cause I feared he would save up the narcotics, and take his own life.
One day, I came over, and smelled a familiar smell, the smell of Weed!
Sure as chit, the Ex Marine was smoking the very Marijuana he hated so much!

Well ... The weed helped him deal with the awful sickness from the Cancer Treatments.
Proof that even an "Old Dog", can learn new tricks.

For me, I find that the mind is like a Parachute, it works best, when it is open.

It took me awhile to embrace Computer Modeling, since I too come from the "put as much wire as you can fit, as high as you can put it, and feed it with open wire line" school of thought.

Remember, I am a 7 (Licensed In Seattle), the land of big ass trees, that are everywhere.
But, I always wondered why my big ass 160 and 80 meter flat tops were deaf on the higher bands.

Or why my full wave low band loop did not play as well, or any better then a dipole.

Today, I look at Computer Modeling the way I look at the 3M Company.

3M don't make products, they make the products we all have better.

And, just like Computer Modeling showed me years ago exactly why my loop was inferior to my dipole, G3TXQ has found you additional gain (from less loss), and an easier to feed antenna, with one very simple change!

Only you know your situation, and if the suggested drooping ends will be safe, or not.

But more then anything, I hope your health gets better, and you beat this Cancer.

Chris











...-.-
10-4, over and out.

The Slab Bacon (Wit da fat meat shakin)

[/quote]

[W2VW]

Keep in mind the feedline transforms the single digit radiation resistance with a short 160 doublet. Helps with matching.

Drooping ends in my case probably makes for miserable RFI and patterns on the higher bands. That would also put the voltage max right near some unhealthy trees. Recipe for fire where it would be difficult to nip in the bud. I'm not folding my antenna, it's just a center fed wire.

I have enough support and room for only one wire. Other stuff in the area would just make problems.

Glad to see the sour grapes guy on QRZ is still well enough to type. Hint. Want respect? Get on the air with something that works well instead of sad, marginal performance. Show us how it's done.

Some of that thread is pretty good otherwise. 

[Steve - K4HX]

I see very few hard numbers or details in that QRZ thread. I'm not sure how anyone could draw a conclusion. Let's use a number that was posted - the feed point impedance of 12-j380 ohms at 3.8 MHz (this is almost exactly what I got in simulating Frank's antenna). Using the VK1OD TL calculator, you get a transmission line loss of 2.154 dB in 70 feet of Wireman 554 (pretty sure this is what Frank is using).

If you put 30 foot vertical ends on a 60 foot long single horizontal wire, you get a feed point impedance of 35.291-j128.09. This results in a feed line loss (same conditions as above) of 0.4 dB.

Assuming the losses in the tuner are identical for both arrangements (I didn't check), you could gain as much as 1.754 dB using the "ends hanging down" approach. Getting away from the absurd three digits after the decimal point and returning to the real world, let just say 1.8 dB. If we use 6 dB per S-unit, this difference amounts to one-third of an S-unit. That's not much when rag chewing over 300-400 mile links with received signal strengths in the 20-40 db over 9 range (the normal application of Frank's antenna).

In the past, I used what started life as an 80 meter dipole on 160 meters by adding vertical sections on the ends. So, I'm fully aware of the utility of this approach. We know antenna design is almost always about tradeoffs and what the designer is willing to accept given space, time, money, application, etc. Seems to me that Frank has traded off a small amount of gain for a small antenna with no portions near the ground to create a safety problem. This is pretty reasonable to me. YMMV.

[AB2EZ]

Bacon

I don't recall ever asking the question that you attribute to me (quoted below).

Can you provide a reference to the thread in which you claim I said this?

Many times I have pointed out that short antennas are not as efficient in radiating the transmitter's power output (into the far field) as a full length antenna, even with a lossless transmission line and a lossless tuner. Many times I have pointed out that very short antennas are very inefficient with respect to the portion of the transmitter's power they can radiate into the far field, and that their near field levels (volts/meter) are much higher than that of a full length antenna.

However... I don't recall ever suggesting that someone who is operating with limited space to put an antenna should not use a short antenna (rather than nothing at all).

I am using a short antenna in my current QTH: i.e. a 50 foot (total length) dipole... which I use quite sucessfully on 40 meters, 30 meters, 20 meters, and 10 meters.

Stu

Now, in a long previous discussion, Stu (AB2EZ) said "Why would anyone want to use a shortened antenna?" I replied to him "Because some of us don't have a choice!" That was the end of that discussion as he usually tends to take the long way around the block, and I am a big KISS advocate.

[ka7niq]

I see very few hard numbers or details in that QRZ thread. I'm not sure how anyone could draw a conclusion. Let's use a number that was posted - the feed point impedance of 12-j380 ohms at 3.8 MHz (this is almost exactly what I got in simulating Frank's antenna). Using the VK1OD TL calculator, you get a transmission line loss of 2.154 dB in 70 feet of Wireman 554 (pretty sure this is what Frank is using).

If you put 30 foot vertical ends on a 60 foot long single horizontal wire, you get a feed point impedance of 35.291-j128.09. This results in a feed line loss (same conditions as above) of 0.4 dB.

Assuming the losses in the tuner are identical for both arrangements (I didn't check), you could gain as much as 1.754 dB using the "ends hanging down" approach. Getting away from the absurd three digits after the decimal point and returning to the real world, let just say 1.8 dB. If we use 6 dB per S-unit, this difference amounts to one-third of an S-unit. That's not much when rag chewing over 300-400 mile links with received signal strengths in the 20-40 db over 9 range (the normal application of Frank's antenna).

In the past, I used what started life as an 80 meter dipole on 160 meters by adding vertical sections on the ends. So, I'm fully aware of the utility of this approach. We know antenna design is almost always about tradeoffs and what the designer is willing to accept given space, time, money, application, etc. Seems to me that Frank has traded off a small amount of gain for a small antenna with no portions near the ground to create a safety problem. This is pretty reasonable to me. YMMV.

Are you neglecting to add TUNA LOSS, into this ?
Plus, you are only considering 80 meters.
Things get MUCH worse on 160

Everything is a trade off, and in the end, we must all do that which we feel is the best compromise, for us.
Franks Antenna works for him, but not everyone has the heroic tuna he has, and not everyone will want to even use true OWL.
Some will want to use lesser Tuna's, and 450 ohm store bought ladder line.

In a past life, I used to sell RV's. In the RV Sales Business, we used to say "There is an ass for every seat".
This does not mean that "Frank is an Ass", of course.
This simply means that different people want different things, from their RV.

[Steve - K4HX]

Tuner losses were covered in previous posts. Or you can run them yourself from the numbers below.

Of course things get worse on 160 meters. There are no free lunches.    I think that fact was well established and I don't think it was ever "advertised" as a 160 meter antenna. Frank uses this antenna only rarely on 160 meters. Functionality on that band was more of a freebie than a design requirement. Frank thought he would give it a try, just to see what could be done. In other words, it's really an 80 and up antenna that will give you something on 160 meters in a pinch. There are many better options (in most instances) for 160 meters. But any antenna is better than no antenna.

Hope to hear you on the air soon.

[ka7niq]

Tuner losses were covered in previous posts. Or you can run them yourself from the numbers below.

Of course things get worse on 160 meters. There are no free lunches.    I think that fact was well established and I don't think it was ever "advertised" as a 160 meter antenna. Frank uses this antenna only rarely on 160 meters. Functionality on that band was more of a freebie than a design requirement. Frank thought he would give it a try, just to see what could be done. In other words, it's really an 80 and up antenna that will give you something on 160 meters in a pinch. There are many better options (in most instances) for 160 meters. But any antenna is better than no antenna.

Hope to hear you on the air soon.

Thanks Steve!
Right now, I am in the process of getting my 40 - `10 meter antennas "all set"
I think it is really cool that you guys here have "kept AM alive" !
I hope to join some of youon 75/80 someday, maybe even 160!

I own 2 big Dentron Tuners, and a Millen Transmatch, and I am "not scared" to use OWL.
In fact, my home is cement block, and I plan to drill some holes right through the cement blocks, and use threaded metal rods, to come into the shack!
No XYL here to tell me what I can, or can't do.
I will do what I please, in the last 1/3 of my life.

Age here is 59, so that means that 2/3 of my life is over, when you think about it!
I fully intend to "Ham It Up" for the years I have left.

[Steve - K4HX]

I like your attitude!

Enjoy it while you can.

[ka7niq]

I like your attitude!

Enjoy it while you can.

Thanks Steve!
I own a small roof cleaning company here in the Tampa Florida area.
I make a living, and that's about it.
But if I had more money and free time, and my business would run w/o me, here is what I would like to do.
I would very much like to get me a RV, hit the road, and Ham it up!

Maybe do like a Ham out west did ?
He found a spot where there was an old abandoned rail road tracks, that used to serve a Silver Mine, on the side of a Mountain.
There are telephone poles along the tracks, with wires running for miles!
He had to repair some of the wires, but he drives up there, and hooks into miles of wire, fed against ground!

The long wire antenna he used has gain lobes, some well in excess of even a Beam!

That's the kind of shit that I would like to do someday.

Or park my RV near a saltwater beach, with an Eagle One Vertical, as close to salt water as I could get.

I live pretty much Inland here in Florida. But those Hams lucky enough to live on salt water kick ass.
I knew a Ham down in Boca Raton Florida, on the east coast, with a Hustler Vertical he had mounted on his Dock, right over Salt Water!
When he called CQ on 40 at night, I swear 1/2 of Europe waited in line to work him!

LOL, one time, during field day, I intentionally drove to the Top of the Sunshine Skyway bridge. It is about 200 ft high, over Tampa Bay!

I had an Kenwood TS 50 in the mobile, and a 20 meter Ham Stick.

I let the air out of my tire (had a few cans of compressed air).
The cops came, and I told them I was "waiting for a tow truck"

That bought me about 2 hours of operation time!!!!!!!!!

I called "CQ CQ Field Day, this is KA7NIQ Maritime Mobile" LOL

In the middle of Tampa Bay, 200 some feet up, and armed only with a TS 50 and a Ham Stick, I was able to hold down a frequency, until I simply got worn out!

So, I simply put the valve back in the stem, inflated my tire, then drove away!

I have always wondered what it would be like to operate on the Great Salt Lake, in Utah ?

[KA2DZT]

You may want to insulate the threaded rods from the cement block.  Use some plastic tubing.  Cement block can store moisture during the rainy season.

Fred

[ka7niq]

You may want to insulate the threaded rods from the cement block.  Use some plastic tubing.  Cement block can store moisture during the rainy season.

Fred

Thanks for the Tip!
LOL, now I am wondering where to get some threaded Copper Rods!