Since I type a bit slow, I'll start off by referring you to the (extensive) collection of information in the "Technical Discussions" page at the website: These discussions go into a lot of the technical details in Zapper design. They comprise about 26 pages in the Bio-Electronics book...
Briefly, Brian McInturff's comment that, 'of the several Clark Zappers he'd made, one knocked out colds, and others didn't...' got me suspecting that it's possible to have a Zapper on a random frequency not generating the desired higher harmonics on a given pathogen's specific resonant frequency....
Let me first say that lots of people are continually achieving very good results with the basic Clark Zapper design - it does work... but only if it gets out of the drawer so you can get a hold of it! (Big Grin)
So once we know that contact induction of resonant frequencies into the body does work, does disrupt paeasites & pathogens, I began to wonder, "how can we *Optimize* the effectiveness? Hulda Clark's book offers a wealth of specific frequencies for a host of specific molds, viruses, bacteria, parasites, tapeworms, etc.; rather than just 'hoping' that a zapper was generating a strong enough harmonic to disrupt a given pathogen, why not really *hit them where they live?*
Several people said, "what about all of the 'RIFE' frequencies?" A Zapper with an output at 30KHz, for instance, may generate many harmonics at higher multiples of it's primary output frequency, but what about being able to use all of the well documented frequencies *below 10KHz*, down to the single digits?
Darned good question; however, the housing used for the Zapper LTS & HFA models, while being very *usable* form an ergonomic standpoint, was internally very closely filled; there was no room to add the required additional controls and circuitry...
The HFA model covered only the Hulda Clark frequency range, starting at about 62,000 Hz (62KHz) and going up to over 1 MHz. The HFA-4 models, with their greater frequency range capabilities and additional control and power options, can do everything that the HFA could do, and more. For that reason, I discontinued offering the Zapper HFA .
The 'AV' on the newer HFA-4 models refers to the updated feature of the use of an ADJUSTABLE VOLTAGE (adjustable amplitude of each pulse) on the output to regulate the amount of power; using the 'wall wart' transformer, the output can be set from about 5 volts up to about 14 volts, allowing experimentation with higher power zapping, while using reducing voltage instead of adding resistance to limit output current drive... results of this approach may give a more 'effective' signal being induced into the body... more on this later.
The Zapper HFA-4AVR model is further modified / enhanced to add a custom built 10 cell 270 mAH Nicad Rechargable battery , along with an extra switch and associated internal recharge circuitry. It can be recharged either from the 'wall wart' transformer, or with an optional 12 volt car cord (or a solar PV panel, etc.) Stopping throwing away batteries is an attractive idea to some. We're not designing a device to run on a single 9 volt battery for a year here; instead, we're working with a higher output experimental / research device that is capable of inducing a higher amplitude resonance into the body, and in the process possibly achieve the disruption of parasites & pathogens more quickly and effectively. (Note: a high capacity rechargable battery system is now being built into the 2005 versions of the HFA-4M(x) series devices.)
I responded:
All of the models can be used to make colloidal silver; maybe I should check to see that I've made that more clear on the web site.
The HFA-4 is capable of being set to any specific frequency from either the 'rife frequencies' or the Hulda Clark frequencies, i.e., frequencies from below 8Hz to well over 1MHz.
The HFA-4 models do require the use of a frequency reading meter to set the desired frequncy. A good source for an inexpensive one is mentioned on the web site. (Check the "SOURCES" page)
For myself & other friends, we're inclined to want to be able to set specific frequencies for specific pathgens or conditions.
If you have specific frequencies from the 'rife' frequencies you want to use, you need the HFA-4AV or AVR. Many asked for the features in this model, including the optional rechargable battery, the wall transformer, the optional car cord for either operation or recharging...
(When working with an adjustable frequency zapper such as the HFA-4AV or AVR, you will also need to obtain a 'Frequency Reading Meter' or frequency counter, such as the ELENCO LCM-1950; more on this elswhere.)
And, of course, the optional CS generator accessory kit can be used with any of these; I always use a hand held multi-meter with the HFA-4 series devices, which monitors the current flowing through the CS generator, to know when I want to end the process.
NOTE: I can only pass on to you the anecdotal reports of successful use of these devices by myself, my family & friends, and other researchers. These continue to offer anecdotal reports of impressive results by a given individual, using a specific device in a specific way in each specific instance; as the saying goes, "your mileage may vary"......[grin]
These HFA-4 devices are more properly "Pad Devices", evolved substantially beyond the classic Clark Zapper 'build it in a shoe box' design. (While some refer to these as "Rife" devices, they are a 'contact induction resonant frequency induction device'. Rife himself worked with *Radiant Plasma* resonant frequency systems, while one of his partners / followers, John Crane, was responsible for the non-plasma device designs, as far as I have been able to discover. Everyone seems to want to use the "rife" label for designs that are really not very close to Rife's own phenomenal work... )
NEW For 2002: the newer HFA-4M and HFA-4MC models have the added circuitry and output capability with special added output jacks to drive the MagPulse magnetic Pulser wands, as well as the light wands; please visit the MagPulse page for further info on these new devices. Also featured on that page are some specialty MagPulse driver units which are built to produce six selectable preset frequencies.
We should all be grateful to Hulda Clark for offering her invaluable information in the first place! I'd expect she intended to provoke further research...
If you're inclined to build your own, and have a bit of electronics experience, the "Build Your Own Zapper / Pulsed DC CS Generator Project" may be of interest.
Please understand that none of the information I share with you is intended to be taken as any form of medical advice; for that, you should consult with your medical practitioner of choice. Information is provided for research purposes only; the "Mission Statement" on The Alternate Health Approaches Forum offers my thoughts on why I feel it's important to offer ongoing tidbits of information...
Call 719-836-2489 for further information (-weekday mornings are the best time to find me able to answer the phone), or email inquiries to stenulson@gmail.com.
NEW 7-31-2007: THE SYSTEM 9C EM+, A RADIANT PLASMA RESONANT FREQUENCY GENERATING RESEARCH SYSTEM: 
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