Peter, whatever happened with Eric P. Dollard?

[madhatter]

guaranteedCosmic InductoriumHoly Grail of Electrical Engineering

Eric, I want to thank you for sharing this, you obviously did not have to. I also feel it has been very informative and covers a lot of information. J.S. Bach "the art of Fuge" is somewhat ironic as although 'unfinished' you have to start at the end in order to start the piece.

Did you work with electron optics as Farnsworth did? not the "electron" verbage of today but the De Broglie wave function pre-the solvay conference.

The hyperbolic function is still a 2d representation of the 3 dimensional function, did you find it limiting?

[t-rex]

Ask Mr. Wizard

Here are some answers from Eric for questions people have asked:

1) Sensitive Device; a rotating glass tube filled with nickel chips. Chips weld to provide a conduction path upon a received impulse. Rotation clears the weld for the next impulse.

2) Break, or circuit controller; an ultra high speed, mercury contactor. A mercury stream is chopped in order to break current path and then reclose it. Speeds up to 10 micro seconds at currents to several hundred amperes. This part of Colorado Springs has never been acknowledged, let alone understood. In the photos it is the drum up in the air by the recirculating coil.

3) Thomas Clockwork; a time piece for the use as a frequency standard of a known omega.

4) "Symbolic Representation of the A.C. Wave", E.P.D.; a shipyard engineering paper, not a book really. E and I, as well as the rest, P, etc., are readings on the scales of electrodynamic , or moving vanes, switchboard instruments. Navy power switchboards contain numerous instruments (relays, meters, etc) for the analysis of complex power flow. The instrument knows not of the actual derivation of e, E, i, I, only the net effect.

5) PI over two; this factor appears twice in the Crystal Radio Initiative, C.R.I. The (20%) secondary coil "effective" propogation velocity is the velocity of light in the space in which it occupies. Here the Pi over two factoris an offsetof a unit value to shorten the winding to compensate for the heavy external loading that the secondary is loaded with, that is, the external inductance and capacitance from the earth and extra coil connections. The aspect ratio of 1 to 1 on the extra coil gives an "effective" propogation of 187% the velocity of light, hence the winding length must be made greater in order to get a quarter wave resonance at a higher speed. This is brought down to Pi over 2 percent, 157%, the velocity of light to compensate for the burden upon the extra coil, this mostly arising from the dielectric upon which this coil is wound. The secondary is Pi over two shorter, the extra coil is Pi over two longer. Golly Mr. Wizard that's Pi squared over four! Do not hunt for magic where it is not, this is all experimental. So go experiment.

6) 62% spacing; an empirical factor, no hidden cosmic secrets here. For its origin go to "Radiotron Designers Handbook", by R.C.A. in Ausstralia. The article "Short Wave Coils" is the basis for the 62%, and the article "Self Capacity of Coils" gives the table for self capacity and the hyperbolic variation with coil dimensions. Referenced are coil pioneers, Butterworth, Medhurst, Autstin, and many others.

7) Conductors; metal does not conduct electricity, this is a primary mind virus. When it is e, or i, the metal bounds the electricity, when it is E, or I, the metal translates the electricity. This is an extremely vast subject so wait. Resistance is NOT one over the conductance. No it is not! The ability of metal to "conduct" is in direct, not inverse, proportion to the square root of the resistance of the metal. Also the more the metal "conducts" in this manner the more the surrounding E.M. wave is slowed. Thus large deviations from the luminal velocity are found in transmission systems in which the physical mass of the conductors all take part in the flow of electrification.

8) Underground vs over ground. Two identical Tesla units will not compare. They cannot receive E.M. waves. For over ground use a conventional crystal set with a dipole, not a ground Marconi antenna. A loop type receiver is even better, a big loop over ground and a big star radial underground. Thus a dipolar connection over ground, a monopolar connection underground. The Landers Mojave Research Installation used a beverage over ground and a wideband Alexanderson underground.

9) The energy required to drive a crystal diode is the same as a telephone signal. So amplifiers are not a way to make it more sensitive. A conventional A.M. radio coupled to the Tesla Transformer is the proper way to add gain (electronic gain) to the system.

73 DE N6KPH

[Gestalt]

TMT Coils & Beeswax?

In the AEPC 2009 conference video Karl Palsness refers to a book where Tesla dedicates an entire chapter with very precise instructions on how to treat high frequency coils.

The instructions are a bit peculiar and I am wondering if anyone knows which book this is from?

- Wind coil in paper form that absorbs the wax
- Put coil in a "Moderate" Vacuum of 29.5"
- Heat at least until 1.5x melting point of wax
- Then introduce liquid wax into vacuum
- 30 PSI pressure on coil while the wax cools
- Impregnate BOTH the Primary & Secondary with wax

Apparently intended results from Tesla's coils are significantly reduced if the above procedure is not followed. I don't know if Tesla was doing this to the TMT later on in his career or some other coil arrangement's with a Pri & Sec?

[Nhopa]

Disruptive Discharge Coil

In the AEPC 2009 conference video Karl Palsness refers to a book where Tesla dedicates an entire chapter with very precise instructions on how to treat high frequency coils.

The instructions are a bit peculiar and I am wondering if anyone knows which book this is from?

- Wind coil in paper form that absorbs the wax
- Put coil in a "Moderate" Vacuum of 29.5"
- Heat at least until 1.5x melting point of wax
- Then introduce liquid wax into vacuum
- 30 PSI pressure on coil while the wax cools
- Impregnate BOTH the Primary & Secondary with wax

Apparently intended results from Tesla's coils are significantly reduced if the above procedure is not followed. I don't know if Tesla was doing this to the TMT later on in his career or some other coil arrangement's with a Pri & Sec?

In the book "The Nikola Tesla Treasury", published in 2007 by the Wilder Publication, LLC. PO Box 3005, Radford VA 24143-3005, www.wilderpublications.com, Tesla goes into some detailed explanation on treating Disruptive Discharge Coils with paraffine oil before use. See pages 127, 128 and 140 for example. So it is plausible to assume that the wax treatment has served a similar insulating purpose for Disruptive Discharge Coils in which the primaries and secondaries were tightly wound in close proximity.

[jake]

Big thanks one again

[QUOTE=T-rex;183317
6) 62% spacing; an empirical factor, no hidden cosmic secrets here. For its origin go to "Radiotron Designers Handbook", by R.C.A. in Ausstralia. The article "Short Wave Coils" is the basis for the 62%, and the article "Self Capacity of Coils" gives the table for self capacity and the hyperbolic variation with coil dimensions. Referenced are coil pioneers, Butterworth, Medhurst, Autstin, and many others.
73 DE N6KPH[/QUOTE]



Has anyone found the reference material listed above. I will post links as soon as I find. I think this simple empirical factor will help with my particular mind virus. If I can get my head around this I will be one step closer.

Also thanks for the crystal radio tips. My crystal radio skills are getting better by the hour. It's funny that an hour of changing inductance and capacitance on a simple coil can teach so much. Even the smallest of changes make all the difference.

Thanks Again,

jake

[jake]

Grounding

Will 10' long 1/2" copper pipes with copper pipe couplings work on the ground system? I ask because the price is about the same but the copper pipes are 10' vs the 8' ground rods.
but more importantly the pipes would let me water drill them into place since I have nothing but clay and rocks below me. It would be slow but easy. Also the pipes would allow me to keep the bottom of the ground system wet.

Thanks,

[Michael Kishline]

In the book "The Nikola Tesla Treasury", published in 2007 by the Wilder Publication, LLC. PO Box 3005, Radford VA 24143-3005, www.wilderpublications.com, Tesla goes into some detailed explanation on treating Disruptive Discharge Coils with paraffine oil before use. See pages 127, 128 and 140 for example. So it is plausible to assume that the wax treatment has served a similar insulating purpose for Disruptive Discharge Coils in which the primaries and secondaries were tightly wound in close proximity.

Correct, good information. Here's what I have Gestalt.

Source#1
"Nikola Tesla exhausted his coils and capacitors for insulating purposes in a pressure tank while melting the beeswax and paraffin mixture with steam permeating the mix into the smallest spaces to force out all gas bubbles, which was the reason his equipment was capable to stand these high electrical pressures and extremely rapid potentials."

Source#2
"Secondary Coil:
The author has wrapped dozens of secondary coils. Their diameters vaired from 3/4 to 4-inches, and have ranged from 400 to 7600 turns and heights from 1 to over 6 feet. Some were built in sections and could be mounted one on top of the other. However, considering size, effort, and efficiency, the best ones were wrapped on a 10-12-inch length of 3-1/2 inch O.D. PVC pipe. Wind about 400-500 turns of #24 lacquered or magnet wire. The turns must not overlap or efficiency will suffer severely.
To make the task of winding go much smoother, clamp a broomstick into a vise horizontally, place the PVC pipe over it, and turn the pipe with one hand while guiding the wire with the other. The dispensing wire coil must turn freely. Pressure must be applied to the last turn at all times, but pauses are possible if you keep a piece of insulating tape ready to secure the last turn and, with a second piece, the last 10-20 turns.
Airplane glue or rubber cement can be used to secure the wire permanently at the ends and in spots along the way. But I found CA glue (Cyanacrolate Ester) or crazy glue works really good and there is no drying time. The bond is immediate. When completed, several coats of paraffin wax, molten candle wax, or bees wax should be used to cover the entire coil, especially at the high-voltage end. That will suppress corona discharge in places where it is not wanted.
the coil is assembled by placing the secondary within the primary as shown in Fig. 2. The base of the coil is grounded. The high-voltage end is fitter with an end-cap that serves as an insulator/high-voltage-electrode mount. Details for a homemade end-cap fashioned from a plastic drinking cup, candle wax, and a doorknob is shown in Fig. 3; the door-knob serves as the high-voltage electrode."

Parts List for the Tesla Coil:

C1 = .003-.005uF, 15,000-WVDC, ceramic capacitor, see text.
L1 = 8uF, 10A, heavy -duty hash-choke, see text.
L3 = 400-500 turns, 24-gauge (#24) magnet wire, see text.
T1 = 5000 volt, 20mA, dual secondary, oil-burner transformer, see text!
F1 = 10 amp fuse
S1 = SPST power switch
PVC pipe (see text), 3-terminal AC line cord, 1-inch diameter brass or aluminum rod stock, metal doorknob (for high-voltage electrode),
plastic cup, candle wax, paraffin wax, or bees wax, wire, solder, hardware, etc.
Copyright and credits:
This article was originally written by Ralph A. Hubscher and published in "Popular Electronics" in September 1990 by Gernsback Publishing, (Gernsback Publishing is sadly no longer in business since January 2000). All drawings, photos, pictures, and other material copyright (C) Tony van Roon, unless otherwise noted.

Source#3
"Points 2-9 are on hints other than oscillator circuit type.
2. PVC pipes are generally good for winding secondary coils. But PVC pipes larger than 4 inches (approx. 10 cm) (inside diameter) are not easy to get since they are not normally used to build nor repair homes. (This is in the USA at least.)
From Robert Eastman ([email protected]):
If one is partial to PVC pipe, for large coils a single large piece of pipe is not the best approach. Rather, make a skeletal coil form from numerous (typically 8 to 12) smaller pipes fastened at their ends to rings of the desired form diameter. I use rings made from PVC sheet (avail from plastic supply houses), or from masonite boiled in beeswax. Not only is this approach cheaper than using a single large pipe, but the form is much less unwieldy -- even for very large forms. Secondly, the dielectric losses are considerably reduced -- as is surface leakage -- resulting in a higher coil Q.
3. Many cardboard tubes, including most thicker ones such as carpet tubes, are too conductive to work well for Tesla coils.
From Robert Eastman ([email protected]):
1) If one is using a cardboard tube as the secondary-coil form, it helps greatly to first boil the tube in beeswax before winding the coil about it. This step drives out any residual moisture from the cardboard, and keeps it out. Secondly, the wax will saturate the cardboard, making it a much better insulator. Beeswax is preferable because of its very low dielectric losses at the frequencies found in TCs (100's of kHz, typically).
(A couple things about this beeswax stuff from Don):
Don't actually make the wax boil. You do need the wax to get well above the boiling point of water to boil out every last trace of water. But if you make the wax itself boil or even get close to this, you produce extremely flammable wax vapors and probably also cause some chemical breakdown of the wax. If you see "smoke" coming from the wax, it is hot enough or even a little too hot.
I don't think beeswax has magically low dielectric losses compared to plastic tubing. However, a waxed thin cardboard tube may well have substantially lower dielectric losses than a heavy thick plastic tube simply by having much less material mass.)
4. If you short or nearly short the top end of the secondary, you may cause any oscillation to fail. Avoid doing so unless the circuitry is known to safely idle with no oscillation.
5. Corona can load down the high voltage output. Due to the corona's capacitance (this effect requires only a few picofarads!), the corona can conduct significant current - often over a milliamp. The corona is capable of burning combustible objects. You should put a "bead" of silicone rubber or a proper top electrode over the top turn of the secondary if you anticipate peak voltages of more than maybe 50 kilovolts - depending on the gauge of the wire, etc. (thicker wire will be corona-free to slightly higher voltages.) Any corona at the top turn may burn the coil tubing. This can leave carbonized spots (usually known as "carbon tracks") which can add to corona problems!
6. The end of the top turn can form a big piece of corona. This can load down the high voltage. This may even develop a bit of jet propulsion which can make the top lead fly around. You may be able to get around this by bending the top lead downward and towards the center of the coil, but with the tip pointing up but below the level of the top turn. Better still is to attach a corona-resistant electrode of some sort to the top of the coil.
(That point is relevant to Tesla coil secondaries lacking a nice big round top electrode.)
7. There is some chance that drawing a spark or even severe corona from the top end of the coil may discharge its capacitance severely and you may not get a continuously arcing spark. I usually got a continuously arcing spark. If you get trouble due to sparks discharging the coil's capacitance, it may pay to use an unfiltered supply to give a pulsating output. But there should still be some significant capacitance across the power supply connections of the primary circuitry, as close to the output amplifier stage (or power oscillator stage if used instead) for the circuitry to work well.
8. I repeat, have a couple hundred microfarads of capacitance across the supply rails as close to the power transistor(s) as possible. This capacitance may well be conducting substantial high frequency current and should be of a type good for this. This may be a parallel bank of tantalum capacitors.
UPDATE 9/21/2008 - Several hundred microfarads of aluminum electrolytic capacitor(s) of low ESR type and with rating for usage at higher frequencies (even is as low as 10 KHz) will generally be OK. Look at the capacitor datasheet to be sure that ESR will be down to a fraction of an ohm and that the capacitor (or bank thereof) will have low impedance well into the 100's of KHz to a few MHz, and that the capacitor (or bank thereof) can easily and safely conduct a few amps of high frequency current. You may need a thousand or two microfarads of bulky aluminum electrolytic capacitor bank to do this well.
For similar specifications, axial lead capacitors are preferred when available.
9. Connect the low end of the secondary to the nearest good ground. Connect the primary circuit's ground to this point, and not too far from the secondary. Connect all nearby substantial metal objects to this point also, and not too far from the secondary. You want ground currents from objects exposed to the secondary's electric field to return to the low end of the secondary in as short a path as feasible."
________________________________________
Back up to Don's Tesla coil main page.
Back up to Don's home page.
________________________________________
Written by Don Klipstein.
Please read my Copyright and authorship info.
Please read my Disclaimer.


I keep receiving an upload error to attach Word Doc.'s so I pulled the info and pasted it here for everyone. Hope this helps.

Great work Guy's

Mike

[dR-Green]

I presume that what you did here is build a matched set of coils, one receiving through the air and the other through the ground?

If they are not then we would need to know the both in air differences?

Ideally two identical coils, one receiving in air and one in a faraday cage receiving telluric?

I don't think that a Faraday cage will work the way you think it will work here. 1# I expect the setup would begin to receive with the coil completely disconnected with only the Faraday cage earthed. It would need to be a decent distance away from the top sphere and the middle of the coil, being a flat spiral, otherwise it cancels all the "magnification" effects of the coil. For this reason I can't place the coil directly on a ground plane, it will need to be a "ground ring" at most so as to not be underneath towards the middle of the coil, or the coil raised further above the ground plane. Reception begins when the coil is approx +20cm away from ground plane.

There are clear similarities between the radio and HV transmission experiments. Most notable is the fact that the coil becomes a mini broadcast station in the corner of the room and effectively boosts, or magnifies as the case may be, the incoming signal. I can get a very nice reception through the normal receiver by using the Tesla magnifier this way. I believe this is what Eric is talking about with coupling a conventional AM radio to the Tesla transformer (plus amplification in that case). It's quite a challenge to find equally good reception where the radio is normally supposed to work, near the window or as outside as possible, and in fact I've found it impossible to find equal reception as far as sound quality goes. It's by using the secondary coil this way I was able to get both receivers into phase unison with the test signal; Feeding the Tesla transformer secondary directly and using the antenna of the normal receiver placed near it to tune into the signal.

The "antenna" in the Tesla receiver is the wire from the C0 plate to the diode, or the plate itself, or even the diode leg/diode. The plate isn't essential in this case. It's possible to hear the signal by putting the wire that's supposed to connect to the plate in the middle of the coil, and I wouldn't be surprised if you could just put the diode itself in there instead of the wire. It's receiving a "transmission" or oscillations from the coil, is a way I might describe it in conventional terms.

[dR-Green]

8) Underground vs over ground. Two identical Tesla units will not compare. They cannot receive E.M. waves. For over ground use a conventional crystal set with a dipole, not a ground Marconi antenna. A loop type receiver is even better, a big loop over ground and a big star radial underground. Thus a dipolar connection over ground, a monopolar connection underground. The Landers Mojave Research Installation used a beverage over ground and a wideband Alexanderson underground.

9) The energy required to drive a crystal diode is the same as a telephone signal. So amplifiers are not a way to make it more sensitive. A conventional A.M. radio coupled to the Tesla Transformer is the proper way to add gain (electronic gain) to the system.

Thanks for the additional info, this confirms a lot of things I'm reluctant to speak about or believe before spending another 10 hours doing tests

[t-rex]

A day at R.C.A. beach

And it came to pass, in the year of our lord, Feb. 14th, 1989, an activity took place in the small coastal town of Bolinas, Ca:

1) Tom Brown, Eric Dollard, and John Costa, proceeded with an attempt to produce a video documentation of the Marconi and Alexanderson remains in the R.C.A. Bolinas antenna field. There was no real plan, it was more of a free form venture. In a conjunction with our endeavor was a planetary alignment and near record solar activity. The perfect day! You could feel the tension in the air.

2) Commonweal had got wind of our video event so their minions in town began the usual harassments. Needless to say the day was filled with voo-doo, and a small cloud followed us all throughout the day as an indicator. I had been blacklisted by R.C.A. at this time in history so there were no friends around for our effort. It is however that R.C.A. Bolinas is a "Cosmic Inertie" for Planet Earth. Even before Marconi the Indians were in awe of the "Hole in he Sky". To compound the voltage, long intervals of "Die Kunst Der Fuge" resonating through the "Cathedral Like" Marconi building, as well as a few masonic versor operations, were conducted during my prior use of the Marconi building. The perfect day at the perfect spot! The cosmic anode.

3) The recording began and relentless battery problems plagued the effort. Then the batteries all were dead. Now what? Tom gets the lame idea that R.C.A. will help us, right! R.C.A., and also Commonweal, have been trying to rid themselves of the "two legged coyote" for years. Tom insists. "No one at R.C.A. remembers you, so let's go". After ringing the door bell the "coyote" cringes and begins to sneak back into the bush. But a new guy, Wayne, answers and welcomes us inside. He became somewhat puzzled when I already knew that all the receptacles in the station were wire grounded twistlocks, so we would need the adapter. About this tiem the "Geiser" shows up in the control room, he worked to close my lab there along with station manager Ed Brennen. Upon his cognizance of my presence, a certain siezure overtook him, like the lady that turns to stone in the Bible. The frozen expression on his face was indescribable. So we bailed out, but with charged batteries. (Wayne was awestruck)

4) We continue down to the beach and then back around for the final scene, the "Fallen Cruciforms" of the antenna wreckage. The batteries were used up. We see a government vehicle working its way towards us from the road. Well who shows up for the event but the head of the Park Service himself, Mr. Sansing. Mr. Sansing came with a special message for me!
"Mr Dollard; we have a group to make sure that there is to be no more electrical experiments here ever again, do you understand Mr. Dollard".

5) No I don't understand, but I know who is in charge of their group, Burr Henemenn. Later in the week the "Gieser" put on a set of headphones. He bypassed the safety interlocks, and walked into BL-10. Upon connecting himself to the 12,000 volt anode terminal he was blasted.

73 DE N6KPH

[madhatter]

Eric, I have a question that I hope you can help out on. In reference to Skin effect and coaxial braid and the velocity propagation of the wave.

For a given Fq there is a calculable skin depth. I can not find at the moment and may have to come up with some calcs on exactly the percentage of skin depth to surface area of coaxial braid is utilized, i.e. for each strand that crosses under another is that contact area now 'lumped'? If the braid is made of insulated wire like litz can the total surface area be calculated as a multiple of all the strands, i.e. 60 wires of 36ga has a surface area of 36ga times 60 for a given length and factoring of course the per turn length of the helical. can it be generalized to where the mean dia of the coax braiding is considered a hollow conductor and the effective coverage percentage is the surface area factor?

This also leads into another factor I noticed, the ratio of wire dia to skin depth, at what ratio of depth to wire dia is best? as the calculation is to 38% of current depth would it be advantageous that a wire dia is 2x that depth?

I was also trying to find wire gauges between the secondary and extra coli that not only were equal in surface area but utilized the same surface area to volume percentage. not an easy task given skin depth and coaxial braid construction parameters.

I did find an Army Navy declassified document by Spergel that outlines the construction and design of the braid. I've yet to track down any of Spergels other published work.

It would seem that the utilization of the least amount of mass of metal but yet the most amount of surface area to the dielectric is what is needed. Given that it would seem then the use of braided coaxial litz wire is best.

off the shelf available wire doesn't seem to be close enough to work with needs of the calculations.

I also wondered given the increase in propagation velocity if the extra coil would benefit from being wound with a decreasing density of wire, not yet clear on whether an increase of surface area or decrease in surface area is needed.

[Web000x]

Eric just called me and asked me to relay the following to everybody:

Don't get caught up in what the skin depth of the secondary is going to be. This is only for a rough calculation of the amount of metal to use in the primary winding. The only thing that is important is that the height to diameter ratio of the coil is correct. Don't get hung up on details. Just build it and see..

All other calculations can be derived from the secondary using the "Radiotron Designer's Handbook". It gives all of the details on how to design coils. This is the most important book ever written on radio technology. If somebody can find a link, please post it for everyone to see.

As far as the wax goes, this was used in Tesla's low frequency designs. Wax was also used for dielectric insulation to minimize corona which in turn added undesirable capacities to the system. Beeswax lowers the magnification factor of the coils.

Eric's voltage converter has started generating again. He said that he cleaned the contacts on it and it started running for extended periods of time lighting a lightbulb with no sources of power connected. The capacitors inside don't have enough capacity for the duration of power observed. He said that he isn't claiming that it is producing free energy, just that the battery that it was connected to happened to climb in voltage over time.

Dave

[dR-Green]

All other calculations can be derived from the secondary using the "Radiotron Designer's Handbook". It gives all of the details on how to design coils. This is the most important book ever written on radio technology. If somebody can find a link, please post it for everyone to see.

Radiotron Designer's Handbook Third Edition

34673570-Radiotron-Designers-Handbook.pdf

Or

http://tubularelectronics.com/Old_Books/RDH3.pdf

Radiotron Designer's Handbook Fourth Edition

AX84.com - The Cooperative Tube Guitar Amp Project

The above 4th edition compiled into single pdf file

http://tubularelectronics.com/Old_Books/RDH4.pdf

[Raui]

Radiotron Designer's Handbook Third Edition

34673570-Radiotron-Designers-Handbook.pdf

Or

http://tubularelectronics.com/Old_Books/RDH3.pdf

Radiotron Designer's Handbook Fourth Edition

AX84.com - The Cooperative Tube Guitar Amp Project

The above 4th edition compiled into single pdf file

http://tubularelectronics.com/Old_Books/RDH4.pdf

Thanks for the links Doc! While I cannot start building for a little while yet it's great to have these references. Can't wait to see what you have to show after another 10 hours experimenting, I'm sure it'll be big! No pressure of course

It's really good to hear from you again Eric, thanks for your clarification on the issues you mentioned. I also found your personal recollection of the Dollard/Farnsworth connection very interesting and am looking for the book you mentioned. I hope you are doing well.

Raui

[Michael Kishline]

F. Langford-Smith Radio Designers Handbook Iliffe books 4th ed 1957

Eric just called me and asked me to relay the following to everybody:

All other calculations can be derived from the secondary using the "Radiotron Designer's Handbook". It gives all of the details on how to design coils. This is the most important book ever written on radio technology. If somebody can find a link, please post it for everyone to see.

Dave

Hello Dave and Eric,

I have a copy in pdf uploading to my Scribd.com page, hope this helps.

Radio Designers Handbook

or

Radio Designers Handbook : F. Langford-Smith : Free Download & Streaming : Internet Archive

Mike