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The "ILA" - Ionic Liquid Antenna Concept by N9ZRT
[Pronounced, "Eye-lah"]
Previously referred to as an IFA, "Ionic Fluid Antenna"


As Presented by David H. Hatch - N9ZRT

IT'S LIKE TRANSMITTING ON A WET NOODLE WITHOUT THE NOODLE!

A liquid antenna? What's that? The N9ZRT-ILA concept ["Ionic Liquid Antenna"], is simply a body of ionic liquid with one of various types of metal probes delivering the RF into the liquid. This highly conductive liquid resonates and actually becomes the antenna. See one suspended from a tree using an abandoned RR track as a counterpoise here. See the same ILA hanging vertical here, and being transported here.

In most cases the antenna is more than 95% liquid, with only enough metal to get an RF transfer made. Where there is more metal in the ILA than just a short probe, we call that a "Hybrid ILA". There will be many varieties of both. Initial reports confirm that the signal reports are most excellent, especially audio quality! Additionally, the antennas made with ionic liquids are very broadbanded. But we are only starting! We need experimenters! As the MAC is to computers, so the ILA concept is to antennae. Both take the road less travelled.

We know the concept works, for we have worked the world on it already. Now, we are testing to see if standard and hybrid variations of it hold advantages over conventional antennae. Read on.

Let me explain one hypotheses about how the N9ZRT-ILA concept may be working...

On the skin effect, let's change that to "surface area effect". We already know that the larger the diameter a metal antenna is, the better it's signal strength. With the center metal conductor in an ILA, the "surface area effect" on the metal converts the signal into what may be what we call "The Pool Ball Effect", a scattering of RF through the ionic liquid and out into the atmosphere, shaped by the housing of the ILA. The floating ions provide a three dimensional surface area, height [when housed in a vertical tube], width as per the diameter of the housing [tube], and depth of liquid. Solid metal will not conduct better than hollow metal, as the RF stays on the outside of the metal, skin-effect. With the ILA, each ion is a floating surface area. My hypotheses is that the skin effect does not apply here as we have another advantage, 3 dimensional radiation.

One hypotheses here is, that the already conductive metal probe is surrounded by and immersed in a hyper conductive solution [Ionic liquid]. This solution has better "hearing" than the metal. It has a "bigger capture area" with it's free floating ions. These free-floaters will enhance, bring in, gather, listen better, and then "report their findings" to the large-surface area of exposed metal, which carries the "report" to the radio. If the hypotheses is right, the larger diameter the ILA, the better listener it will be, not to mention it's ability to "talk better". And proportionately, the larger the ILA, to be followed with a larger surface area on the center conductor [A hybrid design] to make an efficient RF transfer from metal to ionic liquid, and visa versa.

In the years I have been doing this, the thing that fascinates me the most is the probe. In November of 2002 I took an ILA probe to work and was passing it around to the staff. They asked, "What is it?" And for two years the answer is the same, "It transfers RF energy from metal to liquid". In other words, it "translates", it "Hands off the signal from one medium to another". We know a lot about metal as a medium to radiate, but we don't know much about liquid as a medium to radiate. We do know that at the probe, it passes from one medium to another. The larger the probe, the larger the door we give it, the better transfer-surface we give it, the best translator we give it. Such a full length metal conductor would be a hybrid design over a pure liquid antenna. And then, let's run tests and see what that ionic liquid has to say. Can it hear better than metal? Let's ask it.

If this presenter is wrong, stop by and I will pour you a cup of coffee! Why not help us run tests?

Other test questions are:

1.) Which listens better per equal length and diameter between a standardized ionic liquid and a standardized metal using identical ground systems?

2.) Which transmits better [more efficiently] per equal length and diameter between a standardized ionic liquid and a standardized metal using identical ground systems??

3.) Which is more broad banded per equal length and diameter between a standardized ionic liquid and a standardized metal using identical ground systems?

4.) What are the natural lowest SWRs on each band per equal length and diameter between a standardized ionic liquid and a standardized metal using identical ground systems?

5.) What resonant frequency per equal length and diameter between a standardized ionic liquid and a standardized metal using identical ground systems?

* Standardized: That in each test, a standard ionic liquid and a standardized metal would be compared to oneanother, for example: Sodium chloride and water [at a set specific gravity within a set temperature range] as compared to copper.

THERE IS SOME HAM-HISTORY TO LIQUID ANTENNAE

Hams have been playing with liquid antennas for awhile now, but none of them knew about eachother's work until recently!

N9ZRT: Unaware of previous work by other stations, in the summer of 2000 this station created a liquid antenna idea after pondering on the increased signal strength of using the sea as a counterpoise / ground plane. We thought, "If seawater is conductive as a counterpoise, it should work as an antenna too!" Following some experiments, this led to the first "Liquid Antenna" to "Liquid Antenna" QSO that took place on St. Patrick's Day, Saturday - March 17, 2001, 1719 Zulu on SSB at 18.157.50 MHz. The participating stations were WH2AAT in Orange Park, Florida and N9ZRT in Green Bay, Wisconsin. Both stations were operating on 10 foot tall x 2 inch wide "columns of ionic liquid" [In this case, concentrated saltwater]. Also participating in the QSO was W8ZU in Glen Rock, Pennsylvania who was using a conventional antenna. Two Live-Wire Group members, N7PPF and KJ6AP, witnessed the QSO from their stations in Riverside, California and Vancouver, Washington, respectively.

Our first discusssion of the ILA concept was on September 7, 2000 and appeared in this Live-Wire posting. In the early days we called it a "Hydro-Vertical" and some other similar names. You can read the report about the first ILA just coming off the stove and about to go on the air here. In another posting at Live-Wire, KU4FL suggests making the ILA pumpable to resonant length! We tried that over a year later and you can see N9ZUR with the a pumpable protype, and then a video of the bicycle pump moving the liquid upwards in the housing. Other images of the pumpable prototype can be seen here. Maybe you can take it to the next step and really make it resonate with a more sophisticated pump!

We talked to chemical engineer in 2000. We told him what we were testing. He said, "That cannot be done, you cannot make an ionic liquid into an antenna, it won't work." We replied back, "We just talked to Australia on our ionic liquid antenna." He replied back again, "I'll be damned!" That was when we knew we were into new territory.

We began to prepare patent-papers, but time lapsed, and we decided to pour the ILA concept into the Amateur Radio community for grassroots testing.

Also in 2000 when this station was hot on the trail on this new concept, we telephoned an "Ionic Liquid" chemical engineer in England. We explained the concept with him. He was intrigued. As he listened to the idea, he took a type of the various ionic liquids at his disposal and placed the antenna to his AM/FM radio in it. He reported back on the telephone at being amazed how the weak signals on the radio stations become much stronger when the antenna was in the ionic solution. And here lies just one of the yet untested advantages of this antenna. Is it really a better listener? Is it really broad banded, more so than a conventional antenna? Also, instead of the skin effect, is it a "pool ball effect", with ionized atoms knocking into each other in the solution, instead of RF skimming across a surface? There is much research to be done.

You may want to peek through some of the early ILA conceptual ideas, drawings and documents. The antenna has gone through several name changes, as was commonly known as the IFA, "Ionic Fluid Antenna". At the prompting of AB0TJ and because of the proper chemical terminology, we have settled on the current name, "Ionic Liquid Antenna". The images and documents from the early days... An early "Hydro-Vertical FAQ"; An ILA Mobile sketch;.A "Hydro-Vertical All Bander", pumpable to resonant length; Early "Spider-leg" Probe sketches; A pumpable to resonant length ILA dipole using a child's swimming pool as a ionic liquid supply and ground plane; A second pumpable dipole version; ILA suspension trapeze; Side by side antenna test ideas; A wider shot of the test setup.

OTHER HAMS HAVE TRIED THIS BEFORE

An unknown station: During the early spring of 2001 N9ZRT received a phone call from a ham who reported that he had experimented with a saltwater antenna several years back, doing demonstrations to a ham club on 2 meters as well as at the Argonne National Laboratory. We seek out his call, as it was lost in a paper shuffle. From the best of our recollections, he said he had not written an article on his experiment. If you are aware of who this is, please contact N9ZRT.

VE3UGW: On July 7th, 2001 VE3UGW telephoned N9ZRT explaining that he had done experiments with a liquid antenna as well. VE3UGW built a saltwater antenna by filling a piece of hose with a saturated salt solution back in 1995. An article about VE3UGW's work appeared in the September 1995 RAC News Bulletin, apparently a reprint from "The Racoon Times" from Iroquois Ontario, Canada. He writes of his experience...

 
 
    "My tinkering with saltwater was a result of imagination run
    wild.  It started with watching a column of water form on my
    car's windshield.  As I sped up the column elongated, as I
    slowed down it shortened.  At the same time my son was doing
    a school project on conductivity using regular water and salt
    water.
 
    It occurred to me that if salt water would conduct an
    electric current why not RF.
 
    My prototype was a 2m 1/4 wave ground plane with coat hanger
    ground radials and a 20 inch length of plastic tubing for the
    radiator.  I made a super-saturated solution of salt water
    and poured the solution into the tubing.  At the bottom of
    the tubing I had an ordinary brass faucet fitting that one
    would use for an outdoor garden hose.  I soldered the centre
    lead of the feedline to the faucet fitting and the shield to
    the coat hanger radials.  By opening the faucet, I could
    adjust the amount of salt water in the tubing to attain a SWR
    match and next thing you know I was keying up the local
    repeaters.
 
    My next step was to try it out on HF.  Much to my wife's
    chagrin, I cut up one section of garden hose and suspended it
    between two tall pine trees on our property.  Using the same
    faucet and a few lengths of ground wire for ground radials, I
    tuned up on 20m and made several contacts.  The furthest
    being about 700 kilometres.  I did find that 30 watts seemed
    to be the threshold.  If I kept the power below thirty watts
    the SWR remained stable. Once I exceeded thirty watts the SWR
    increased proportionately with the power applied.  I don't
    know if the solution began to boil or if there were other
    factors involved, but it didn't like high power.
 
    That was the extent of my experiment.  I know it works and
    the contact I made at a regatta in Sault Ste. Marie was
    baffled by the description of my antenna but that's what
    ham radio is all about."

And the from here the concept is now being perfected, tested and published. The "How to do it" plans are now available. Start with the basic ILA housing and probe in a PVC and go from there with your creativity.

OTHER HAMS ARE NOW EXPERIMENTING WITH THE N9ZRT-ILA concept

The Live-Wire Group: Tests on the ILA concept continue through members of the Live-Wire Group. New testing stations are encouraged to join in as we break ground on a new RF listening and receiving concept. How about you? Why not build your own version of ILA concept? See the work KG0HO and N0LX are doing with the N9ZRT-ILA concept.

Experimenters are asked to link to this page as the hub for their test reporting.

AND THE TESTS REVEAL...

Primarily the ILA has been tested as a vertical, using various counterpoises. It has also been tested horizontally when mobile. Prelimiary experiments show that the ILA concept has a low "Q", that is it is broadbanded, hears weak stations especially well and transmits an exceptionally crisp audio signal.

About the ILA concept being fast on the CQ-response, N0LX reports on his 20' x 1" ILA, "I fired up the FT-817 and made 9 QSO's on 5 watts from Tennessee to California from here in Golden, Colorado!"

About the ILA concept being broadbanded, KG0HO reports that with his 20' x 1" ILA, "My 746 will tune the ILA on 6, 10, 12, 15, 17 and, 40 with no problem at all, with 100 watts output."

WE SEEK AS MANY TESTING STATIONS AS ARE INTERESTED

Testing stations are encouraged to:
1.) Place their ILA concept prototypes in the ILA Registry
2.) Sign on to Live-Wire Group where the experimenters are gathering.
3.) Please log your work in the ILA Concept Standard Test Reporting Form For Experimenters.
4.) Please load your test results for public viewing here, as many folks may be interested in seeing what we are learning.

ABOUT IONIC LIQUIDS

Ionic liquids are finding new applications in industry. Why not in RF transmission as well? Some ionic liquid labs will create a "Designer Ionic Liquid" for you, as per your specifications. From this experimenter's point of view, any ionic solution we Amateurs use should A.) Be safe if spilled, B.) Should be as conductive as possible, and C.) Should be cost effective. For test purposes, we suggest experimenters start out with table salt. See this awesome chart about Brine Conductivity with saturation and temperature variables: http://seagrant.oregonstate.edu/sgpubs/onlinepubs/h99002.pdf

Specific gravity [SG] is one easy measurement of the conductivity if salt solutions, and getting it just right has it's guidelines for measurement. The higher the SG of saltwater, the more conductive it is. We have obtained a SG of 1172 while N0LX reports a saturation level of 1179! Compare that to seawater: Different oceans have slightly different specific gravities. The tropical Indo-Pacific has an average specific gravity of 1022 - 1025. The Caribbean has an average specific gravity of 1023 - 1026. The Red Sea has an average specific gravity of 1028 - 1035. The specific gravity changes in each area are due largely to rain fall. Live-Wire member, Harry Kholer-N0PU, uses a Liquid Conductivity Test set. This test set would be nice to have, as conductivity of salt solutions varies alot as per the temperature of the solution.

HOUSINGS

Most testing stations have used PVC of various diameters and lengths. Note that some PVC contain metal, and so be a true ILA, I would steer only toward pure PVC. Some stations are testing flexable hose as housings. Garden hoses have been filled and used. Rain gutters could be plugged and filled, then tuned up. Anything that can contain liquid, and then an RF probe inserted into, will work.

PROBES

Here is the latest probe, a "Spaced-Washer" ILA probe concept allowing more metalic surface area at RF-in, yet keeping the metal portion of the antenna to a minimum. We would suggest this probe to be the standard in all tests. See more pictures of the "Spaced-Washer Probe": 1. [With the washers misaligned like a cam shaft to allow liquid to pass by], and 2.

 [complete from the inside] and 3. [Showing the outside with an RF-connector attached]; 4. and 5.

The "Spaced-Washer Probe" is an enhanced form of the simple stainless-bolt probe. Early ILAs by this station used debraided copper cable, formed into "spider-leg" type probes. These worked excellent, but left lots of gaps for leaks at the feedpoint. You can see a similar spider-leg probe in immersed in ionic liquid in a Pyrex housing ILA. The Pyrex version was created to see if we were dividing molecules and creating hydrogen bubbles and was made from a milk-transport tube from a dairy parlor here in Wisconsin. We never saw any bubbles, darn it! :)

About probe leaks, KG0HO writes, "I've stopped them using candle wax. You can put it on the inside then melting wont be a problem in the summer."

GROUND/COUNTERPOISE SYSTEMS

Anything that is "electrically larger" than the antenna itself, and that is not polluted with noise will work as ground system. Conceptually, a pure ILA station may consider suspending a vertical ILA over a child's swimming pool that is of the same ionic liquid, using that pool as a ground system. Why not? Some stations report using ground rods next to their ILAs. N0LX has gone "Marine Mobile" with his N9ZRT-ILA concept, and dropped a bare wire into a lake, allowing the lake to be his ground. Early tests with the ILA by N9ZRT used his old Jeep as a counterpoise, or the body of his van as the ground system when taking the ILA as a mobile antenna. Here is an ILA suspended over an abandoned RR track where the tracks have been exposed and are physically connected as a ground system.

MANY CONFIGURATIONS

At this writing, 11-28-02, we feel the best design to make the ILA concept pumpable to rez-length, will be similar to these images, submitted by N0PU and N9ZRT 1. and 2.. NOPU's idea is superior in that the probe is inserted from above the waterline, minizimizing water leaks.

The ILA can be configured as a vertical, a sloper, a dipole, a loop, a "V", an "Inverted V", a "long-hose" [In the wire-antenna world, that would be a "long wire"] and so on. Be creative! You may be the first one to try one of these configurations! This station has created an ILA Concept Hybrid, wrapping the PVC housing with copper ribbon, as a coil. You can see the various images of this hybrid here. Mahy other hybrid versions will follow. Perhaps you will make one yourself.

MAKING YOUR OWN ILA

Here are the basic construction steps for the N9ZRT-ILA as we suggest it: We use these basic parts [Probe materials not shown].

1.) If you are making a saltwater ILA, boil water and dissolve Morton-type table salt until you can dissolve no more. Stir constantly. Watch out for hot-spit from the batch. Let cool and if you have a hydrometer [Wine and beer supply shops], measure your specific gravity and record it. You will need a hydrometer than measures at least 1170. You will also want a tall narrow cylinder to contain a portion of the batch in when measuring the SG. If you are using another ionic liquid, take all safety procautions.

2.) Take a PVC cap, drilling an appropriate sized hole in it, depending on your homemade probe. Design your own probe, or use one of the designs below, in the order of this author's preference.

A.) As noted above under, "Probes", buy a fully threaded stainless steel bolt, 1/4 inch x 6 inches is good, round or square head. Also get 4 or 5 large stainless washers, 10 smaller washers and 8 or 10 matched-thread stainless nuts. Here is the latest probe, a "Spaced-Washer" ILA probe concept allowing more metalic surface area at RF-in, yet keeping the metal portion of the antenna to a minimum. We would suggest this probe to be the standard in all tests. See more pictures of the "Spaced-Washer Probe": 1. [With the washers misaligned like a cam shaft to allow liquid to pass by], and 2.

 [complete from the inside] and 3. [Showing the outside with an RF-connector attached]; 4. and 5. Then, add silcone by drilling a hole and squirting it through until it comes out here.

The idea is to have a metallic exposure of RF immersed in the liquid, but not so much metal that it is more of a metal than a liquid antenna. Fit the bolt through an undersized hole you will drill in a threaded PVC cap, allowing about 1 inch of the bolt-end to protrude outside the cap. This is where you will attach your RF-hot lead. Here is an image of the RF-connection on the original N9ZRT-ILA concept [Note, this is not a PVC threaded cap].

B.) The second choice of probes would be a simple stainless bolt like above, without the spaced washers. This probe is also highly effective.

C.) If you want to be nostalgic, build N9ZRT's original-type spider-leg probe. If you do so, expect the saltwater to be very hard on the copper probes as seen here and here. Also, the spider-leg probes tend to leak, and when the saltwater hits aluminum, it works a number on it too, as seen on this dripped on RF connector. Cut a 6 inch length of a 1/4 inch or so copper braid. You can bend a short "L" into it, or keep it straight. If you bend an "L" that will allow the probe to come out the side of the PVC cap. If straight, it would protrude out the bottom of the cap. Then solder section that will protrude so it is solid [So to get a better seal and for non-collasping of the braid when an RF connector is screwed to it]. We sometimes keep the probe from pulling through the hole by using a "J clip" and the special pliers that go with them, used for rabbit cage construction. These clips encircle the copper braid and make a "stop" point so it cannot be pulled out of the PVC cap. Push the copper through the hole and debraid it into "Spider-leg" type probes. Add an RF connector to the section that is exposed. Now use silicone to seal the hole.

3.) On the top of the 10-foot x 2-inch PVC, place a threaded PVC end-cap and a rope/hose clamp suspension system. If you like you can also just glue a standard cap on, as shown on this N9ZRT original ILA. Using a funnel, carefully fill the PVC tube with the cooled solution, keeping the filling-end as high as possible. Using Teflon tape, screw on the bottom probed-fitted cap and suspend, if yours will be a vertical. Then go on the air!

Once again, testing stations are encouraged to place their N9ZRT-ILA concept prototypes in the ILA Registry and sign on to Live-Wire Group to share test results. We have an N9ZRT-ILA Concept Standard Test Reporting Form For Experimenters. And place your report here for all Amateurs to learn from.

Presenter - David H. Hatch, N9ZRT - n9zrt@arrl.net