Build Your own 27 Mhz Epilator - using CB radio

If anyone is interested, I have just ordered a Midland model 1001Z CB radio with the intent to try and rig the device to perform as an epilator. If others are interested, I may put up a web page showing the steps in the conversion of this unit.
This will be an interesting project for me. Operation will utilize CB channel 14. I may end up gutting a good part of the radio, but I could not even begin to purchase the parts I will use, for the price I paid for this radio. Unit and shipping came to less than $34.00 from Mogiz, LLC. I was able to download the owner manual from Midland.
Anyway, anyone let me know if they are interested in following my CB to Epilator conversion.

You know we have lots of Do-Each-Other-Electrologists and DIY’ers who want to know about this. After all, we have people building boot-leg One Touches and Vectors on this board.

Update on progress:
I have ordered the CB, it is due to arrive on Monday.
I have contacted Midland, and they emailed me both the schematic and a block diagram. This is going to be a fun mod.
The first thing I want to do when the radio arrives is to document the signal levels at different stages of the transmitter.
Next I want to rig the transmitter so that it does slow thermolysis using and external pulse generator. This conversion is very easy. I will use the ext. speaker jack to feed the pulse into the radio. It will trigger the power transistor with a negative pulse on the emitter. The output transistor can easily handle even Microflash speeds based on its power ratings. But initially, I want to keep the power level down and compare the 27 mhz with my 13.5 mhz clareblend ultrablend. That will give me an exact comparison on the effects of 13.5 mhz vs. 27 mhz. After completing that checkout, I wish to remove a lot of the unused parts, and to build a galvanic circuit for the radio. This will permit Blend to be performed using 27 mhz.
What I would like my final project to be, is to up the power ratings and to control setting with a real computer using the usb port. All setting will be controllable from the computer. This will be something that could even be marketed. Settings would be able to be save in client files along with time and anything else one would want. I have some programable IC’s being sent to me to experiment with.
Anyway, that is a little update. One will certainly be able to make a 27 mhz thermolysis epilator for less than $100 and very little more for a blend unit, but the blend will require more time, as lots of parts will need to be removed, to make space for new circuitry.

For anyone interested. Today, I recieved my Midland 1001Z CB. I took some initial level measurements. Without modification, I get about 30 vp-p at the antenna terminal. With this level, thermolysis epilation normally will occur in a half Second to a little over one second. If doing thermolysis on yourself i.e. DIY then you can probably get by using manual keying of the microphone.
If you wish to work with a foot switch, a switch can be wired to a microphone connector between pins 3 and 1.
Now about probes. I find a vast difference in the effectiveness of different probes at this frequency. The worst cords to use, that I have on hand were the Clareblend BNC probes. I have two different probes, and the signal loss on both went down to only 6 volts peak to peak at the tip. Using Dectro probes for my cleo or other 13.5 mhz epilators yealded about 15 volts p-p at the tip. I had modified one probe to use a BNC connect, and another one with just a banana plug for Glavanic use in my experiementing. My recommendation, would be to use a UHF to SMA adapter on the output of the CB and then to use a cable made for the Apilus Platinum. The cables that are in use for the 13.5 mhz machines are just not very good at 27 mhz. Epilation will occur very quickly, but at these levels it is managable for those wishing to use something on themselves. I will recommend having a timed circuit before suggesting anyone even consider using it on anyone other than themselves. Manually, you will feel the heat being generated and will know when you have generated enough heat.
I wish to get this probe loss problem out of the way, before I run a test to see if 27 mhz is really much faster and less painful the 13.5 mhz. I will probably, search for my own cable and make up my own probes if possible. But for those who would like to get started using something cheap, and readily available, this is something someone may want to consider. It is not as capable as my Cleo but RF wise it is almost as capable as the thermolysis on my Clareblend/Ultoblend Ultrablend.
Shortly, I will pick up my IC chips and get started on building a pulse generator. Also, remember for now, that the frequency authorized for medical use is Channel 14. Just make certain that you are on that channel.

Update on using a CB radio as is - for an epilator:
I have found that hairs do release very quickly at 27 mhz. With the levels observed on a scope, I expected it to take about half a second for epilation to occur. What I have found is even a brief duration of about 1/10 of a second can cause spots which initially do not appear, but later appear and last up to a week or so. This indicates that even a tenth of a second at 27 mhz with level that would take longer with a 13.5 mhz machine does indicate its timing may be to long.
My recommendations are that if anyone is considering using a CB without modification, to use it that way only in areas less visable until you have enough experience with the machine to progress.
It is true that with very quick pulsing of RF energy, that I was not even able to feel the heat. It is when I felt the heat, that I later see tiny raised areas which seem to last for a lot longer than my experience with 13.5 mhz. There is certainly enough energy in a CB radio to kill hair. It is now up to controlling that energy so as to not over-treat.
Next project step is making a pulse generator to perform accurate timing operations.

Now you see why the Apilus Platinum does NOT allow continuous foot pedal operation. One can only make a setting and even if the foot pedal is being used, it delivers the measured dose of energy, not a steady stream until the foot pedal is released.

Yes, James,
I must admit, that I was very skeptical that there was really that much difference between 13.5 mhz and 27 mhz. But even my first most basic tests are proving there really is a major difference between the two frequencies.
I have ordered parts to make a little circuit card that uses a simple CD4013 chip that will serve as a one shot pulse generator for my next step. Parts for two circuits only cost about $4 from Allied Electronics. So that works out to about $2 apiece. The volume control on the CB is perfect for the timing control. I am pleasantly surprised at the power capabilites of the output transistor in this unit. It is rated at 4 watts at 12 volts, but it is capable of 80 volts, and is rated for 10 watts. The output on the Clareblend Ultrablend is only rated of 7 watts. Its maximum voltage collector-emitter is 65 volts. So this CB has components rated higher than the Clareblend.
I really need to see about ordering a probe used with the Apilus Platinum. Trying to purchase good RF cable in short lengths looks like it is going to be difficult. Also I am finding it difficult to find the connectors used on the end of the probes for inserting probes. I really wonder who makes them. But like apilus, I would most certainly keep the SMA connector for cable to unit attachment.

Need I remind you that Texas Electrolysis Supply could have you a Platinum cord in a jiffy?

One of Apilus’ main issues was the class of electrologists trained to “find the edge of the client’s pain threashold” when creating a treatment setting. Can you imagine the damage a Platinum would dish out is it were set high enough to actually HURT?

James,
Yes, Texas Electrolysis Supply is my major supplier along with Dectro California. Either one supplies my needs very quickly. I have ordered some things through Prestige, but delivery seems to take just a while longer. But much much faster than Electric Spa which took 3 weeks just to get me some sample uniprobes and a H forcep. But, to their credit they did offer free samples.
This is Labor day weekend, so I will hold off for the holiday. I do not want to be in too much of a hurry. I like to think things out a bit, and to work in stages. This project allows me to do just that.
There are even more options that I could add to the project as well. If I key the epilator as I plan at the final output stage, I can also make a little audio oscillator and feed the mic input and produce modulation like I believe the VMC does.
Also James, about pain - The reason that it hurts less is because the heat generated is maintained in a very small space. If however, someone not trained in the proper probe placement, happens to fire off the epilator where the nerves are in the follicle instead of at the bottom where the papilla resides, then they will really experience what pain is. I really believe that someone wanting to use this modality, really should know what they are doing. They should be able to look at a hair and know what stage of growth the hair was in, and to be able to be able to tell how deep the sebacceous gland, by observing the moisture layer around the hair. They should be able to identify what areas have cells capable of generating new hairs. Someone should not just purchase or make an epilator and figure that is all they need. But if someone is willing to put in some time learning what is going on, it should not take $8000 to purchase a good 27 mhz epilator.
I really do believe that Dectro is a wonderful company. I do believe that Apilus is probably the best machine out there. For someone just starting out, I believe they are the way to go. I back that up, with my own experience. That is why I went to them for training. You will not find an easier machine to operate - especially for a beginner.
I for one, have always believed in providing as much versatility as possible in anything I use. When I worked at Boeing, I helped to keep every available option available for the operator to choose from. On my final version of the conversion, that is what I wish to strive for in this project. All parameters available on a computer screen that an operator can choose from. Manufacturers have done a wonderful job of making something very portable and simple to use. My idea might not be as portable - being that it will require a personal computer like a laptop to interface with it. But it will not have the costs and breakdowns associated with touch membraine switches. Those processes are just out of reach for Do it yourself construction.
Personally, I think that prices will come down after other companies also start marketing 27 mhz machines as well. We will see, or at least I hope that happens. I will readily admit that I am so glad that electrolysis as a field has not remained still over the last dozen years. Knowing what it was like for me going through electrolysis that long ago, really makes me appreciate the differences being offered today.

Buyer Beware: Prestige Electrolysis Supply is NOTORIOUS for botching orders, sending you something other than you ordered, and refusing to make good. I don’t know anyone who has used them for a year without having this experience. They even had the nerve to argue that I had ordered a WOMAN’S Lab Coat with my name on it, instead of admitting that they either could not get a men’s coat, or were just so used to serving women only that they just typed in the usual F in the computer when filling out the order to their subcontractor. I still have a delux FEMALE lab coat, still in the plastic with MY name on it because they patently refuse to admit their error.

Now this is just the most egregious case, but almost every time I ordered with them, at least ONE thing on my order (I don’t make orders without it being a list) would come out botched (typoes in the data processing dept perhaps?) and I would receive something that I did not order, (but had paid for) and would be missing something that I had ordered. Their cheerful customer service response was always the same, “We can go on and order that other item you missed now, what credit card do you want to put it on?”

Long story short, I don’t know anyone who has not been burned by that experience with them at least once.

On the other subject, I don’t see any indication that there will be a crowd of 27mhz machines coming to market any time soon. All Apilus’ competitors are sticking to the line that 27mhz either doesn’t exist, or that it doesn’t offer anything to the treatment, or that it is just a promotional gimmick that has no actual value to the industry other than giving them an excuse to charge more since no one else is bothering to do it.

I wish I had you there for some of the arguments I have had so that you could talk the technical talk better than I could. In one combative conversation, a certain Apilus representative was challenged “First 13mhz, now 27, why didn’t you do 54mhz if higher frequencies are so good?” The simple reply was, because the higher the frequency, the more you must be concerned with the control of the treatment energy, and the powersupply issues increase. It made sense to me, and you seem to be finding the same thing.

Oh yeah, and they also had a time of it trying to fit everything into the shell they wanted to use for the epilator when making the Platinum. Anyone handling a Platinum, SX-500 and Cleo can instantly tell the machines get heavier as the price rises, and since I have seen them all “open case” I know there are no lead weights in there to make that difference. All the extra weight is extra parts.

James;
Until, I tried the 27 mhz on myself, I include myself among the skeptics. I have worked with microwave frequencies, and electrical characteristics do change as frequency increases. Cables loose more energy, even small circuit traces can become antenna and radiate to other parts of circuit boards etc. I will try and explain the power supply part of the Problem. If a certain amount of energy is required in order to generate enough heat to destroy a hair, and you then decrease the amount of time that amount of energy is present, you must then increase the amount of energy in that shorter time period. What that means is that you need a Power Supply that can deliver a large amount of energy very quickly, but spends most of its time just idling by with just supplying power to electronics in kind of standby mode. One can either built a super super heavy duty power supply to be able to handle the highest currents available at any time, but that power supply would require much more current from an outlet. Another option is to build a supply which has a super amount of capacitance. These Capacitors store energy and can release it very quickly. Another consideration is that if the resistance stays the same, than the voltage must increase in order to deliver that energy in that amound of time. My cleo reaches voltages of 160vp-p at 99%. At that level it is possible to get enough energy to kill hairs in a time very close to a hundredth of a second.
The output of the CB surprised me with 35-40vp-p on its output. I thought it might be limited to its 13.5 volt power supply. But that falls right in the operating range of my Clareblend Ultrablend range. One means of experimenting with output levels is by means of a Step Up transformer. A step up transformer, ups the output voltage while decreasing the current. It does not increase power by any means, but does alter the voltage and current. I have read on the internet that the impedance/resistance of human skin is about 950 ohms. Yet a CB is designed for a 50 ohm load. One way to correct for that would be to use a simple 1:16 balun. With such a transformer 20 volts of rf now becomes 320vp-p. This would be twice the maximum voltage out that my cleo can handle. Current decreases, but that is really what we want anyway. Very very low current. And fast switching time. So modifying the output stage is advantagous. But part of what I need to check out, is if the transformers work at very fast pulses, as they rely on inductance in their operation. But before changing the output stage, I want a means of generating a very quick one shot pulse. Parts for such a circuit will shortly be on their way to me.
Here is a URL of a place to purchase such transformers:
http://www.communication-concepts.com/hf_transformers.htm
You may be able to see, things can get out of hand very easily with these kinds of levels. That is why I will take things slowly, and make certain things are working as they should before proceeding.
Some DIYers might be more comfortable, just keeping the voltage where it is and just using Flash timing. So I will work with the easiest mode first. Just give the unit controlled timing curcuit and that can be done. For Micro and Pico Flash, that should only be for someone really knowing what they are doing.
As far as weight on units. The power supplies are the heaviest items in them. IC’s do not weigh a whole lot. Transformers tend to weigh a lot. Large Capacitors can add some weight, but when compaired to Transformers, their weight is minor. I might venture a guess here, but when using multiple pulses on an apilus machine, it is known that subsequent pulses after the first pulse will be about 20% less. This is more than likely due to the power supplies capacitors not having reached full charge by the time the subsequent pulses are delivered. So if you want short durations between pulses, again the Power Supply must be beefed up. Thus again more weight. The power supply for the CB is external, but might require a heavier duty supply than I am currently using. I will find out as I get more into the final stages of my project, where I will want the pico flash timing.
Thank you so much on the warning about Prestige. The American Institute of Education in California, I believe uses them a lot. But Texas Electrolysis Supply has been pretty good by me so far.

One added thing I am beginning to think about now. Whether to add a blend option for the CB mod. As I said, I expected much slower epilation times stock but now I realize I need to drastically reduce the RF level out for blend, otherwise the RF will just vaporize the Lye rather than just warm it a little. That can be done easily enough with just a adjustable regulator supplying the output stage, or by decreasing the pulse drive if directly pulsing that stage. There are several options. But I now see, that power will certainly have to be dropped in order to offer a blend option.
Again, somewhat just thinking out loud here. With using an existing transmitter, much of the design work has already been done. Parts layout has already been perfected and there is no need to redesign the RF oscillators and drivers. There is absolutely no way, that I could begin to design even one stage for the price of the complete CB. All I need to do now is to go in and make the output controllable for the purpose of hair removal. The major design work has already been done.
For that matter, 54 mhz could also be done, as that resides near the amateur radio 6 meter band. But most people need a Amateur Radio license in order to purchase such a radio. The 27 mhz band does not have such a requirement. So it is much easier for someone to get ahold of the transmitter than it would be for them to get a 54 mhz transmitter. Besides that, 27 mhz CB radios are much more mass produced, leading to extremely cheap prices. One is not going to be able to get a 6 meter transmitter for the 30 or so dollars that I spent. So in keeping things cheap 27 mhz is the way to go. It is cheaper to make the CB conversion than it would be to even purchase a amateur radio 20 meter (14 mhz) transmitter and modify that. One again a license is needed, and again prices are higher as not as many units are sold. So from a DIY perspective, it makes logical sense to use what has already been developed and to just make the modifications that are needed. Yes, there may be some tweeking as I get further along in the modification, but I really believe this is a viable project.

Everyone,
This is why I take things slow in my testing. My 50 ohm load has a centertap to allow messurements at 50 percentile. When taking my initial RF output levels, the scope was moved to this 50% tap, but I forgot to double my measurements. Tonight I went back and double checked my measurements and found my mistake. So instead of 35 volts P-P Rf level, the true RF level out of the CB is 70 Volts Peak to Peak. This is more than I can even get out of my Clareblend Ultrablend. I removed the microphone from the cord, and used a function generator to serve as the microphone switch. What I found is that from the microphone jack I can Key the transmitter at less than 0.0001 seconds pulse width. This without even modifying the output stage. So this is what my first Thermolysis RC conversion is going to look like. Microphone removed and cable attached to a bud box. Wire to turn receiver on - Red - will instead become V+ to power the circuit that will be installed in bud box. The box will have a jack for a foot pedal and one or two controls. Initially, I will probably only use one IC which will deturmine the amount of time the unit will be on for each foot press. If I decide to had a second chip and a “AND” circuit, I can easily give periods of pause in the RF energy. This can easily be accomplished with even 555 or 556 ic chips. I am still considering how I want to control the RF level output. 70v P-P is on the high side of most of Apilus’s predeturmined settings. Energy units are almost 500 for a pulse duration of just 0.1 seconds. So one can see how too much energy can quickly be delivered. Parts are still pending delivery to me, so I am right now waiting on my parts. I probably will need to build a adjustable power supply to power just the final transistor. That will probably be step two of the first mod.

Everyone;
Today I recieved the parts that I ordered. I built up two circuits using little printed circuit cards that are about 1.5 x 1.5 inches. The boards only cost a couple of dollars and are big enough for the circuitry required for the timer.
One note of concern on my project is that because the timer is operating so quickly, a pulse is generated both when pressing on the footswitch and again when the footswitch is released. I may want to look around for other circuits that might not have this problem, but for now, I think since this is for the DIYer, as long as they know about the difficulty and wait till after removing the probe before releasing the footswitch it works fine. I am changing component values for the timing because I would like to use the volume control for timing and it is 10k ohms, whereas the schematic is using a one megohm variable resister. For a maximum timing period of 0.1 seconds the capacitor should be about 10 microfarads. I now have a 47 microfarad cap and it gives me about 0.4 seconds. With the 10 kohm pot turned to minimum resistance, the fastest pulse is about 0.001 seconds. Also instead of using the Q output of the flipflop, I am using the not Q output - in other words - pin 12 instead of Pin 13. This produces a negative going pulse which triggers the transmitter wonderfully without having to go through another transistor to reverse the signal. Might as well use what is built in the chip. Something else to consider for the circuit is that the footswitch is switch B+ or 13.5 volts and so you will want to make sure the jack is insulated. If built in a blastic box, ther is no concern, but if using a metal box, keep in mind that without insulating the jack, the box will have B+ on the chassis. I have only spent about $10 for everything for this circuit so far. For someone wanting something very cheap, this should fit the bill. More info to come.

I have finally initiated a webpage for this project:

http://marthajoy7.clearwire.net/CBconversion/

This circuit will work, especially with someone who wishes to use the two pulse technique. I found that since the foot is on the switch for longer then the pulse duration, it also give another pulse when the foot is removed from the switch. I may look into being able to fix this possible problem, but for the two pulse technique it will work wonderfully. Insert to depth, put foot on footswitch, withdraw probe a little bit and take foot off of footswitch. Then finally fully withdraw probe. A different pulse generator that I would like to use, may not have this reaction. It uses switches to set its pulse durations, instead of a variable resistor like I am initially using to check things out. With my current setup, I am able to generate pulses faster than 0.001 and as long as 0.5 seconds by using a 47 microfarad capacitor, and a 10K ohm variable resistor.
Anyway, I wanted to let people know that I now have a webpage set up for this conversion.

Martha, you are truly unique. Although I haven’t had the time I want to keep up with the board, I have read through this thread and visited your site. I think it’s absolutely great what you are doing. Too bad NoHair doesn’t jump in on this thread and try doing this too. He was such a big advocate of DIY, and DIY machines.

I was actually talking to Dr. Heimlich at Texas Electrology Supply today. We had a few good things to share about the machines he’s outbidded me on. It was actually fun talking to my great deny-er of some really good machines, and telling him of the two I snaked from under him. Anyway, he was telling me the history of all these machines. He’s been in this business for some time and he really is a wealth of information. I urge you to call up T.E.S. in Houston, order some small supplies, and try to get Dr. Heimlich on the phone. Actually, I think there’s only one other person that answers their phone, and they are both extremely nice people. Anyway, He was telling me about all these ideas that have been ‘borrowed’ from one company to another, that the 27 MHz epilator idea is really about 35 years old. Apilus went back to the old Proteus 3700 Epilator (I think it was the 3700) for the technology. They just upgraded it, and then borrowed from Kree the winding concept to boost the power output. So really, there’s ol’ Apilus borrowing techology again, like the way they took techology from the Silhouet-Tone Sequentium 328 to design the Apilus Senior motherboard, and they really didn’t even do it as good. The Sequentium 328 still has better galvanic delivery and stairstepping capability. They were sued in litigation for that. I have an Apilus, and god knows that I think good of Apilus. They conduct research and testing, they give to the schools, and they try to accomodate customers on the phone. The Apilus is neat, it’s pleasant, it’s fast, it’s accurate, and easy to use, but I still want credit to be given to these earlier pioneers that developed the technology, and did it better with less resources.

It’s good that you’re doing what your doing. I hope you upgrade the website to guide novice electrical techs on the construction of a 27 MHz system. I may actually attempt this myself. Try getting ahold of Proteus, maybe someone still has schematics that you could use.

Mantaray

Ps: Oh C’mon James, were the size 14 shoes that went with it an accident too, huh? HAHA! I’m totally kidding here of course. (in german psychologist voice): ‘Deed zyour mozzah beat zyou? Deed zyour fazzah beat zyou? Vhat vas zyour earliesk memoriesk?’

Mantaray;
You could very well be a benefit to this project. I know that I tend to speak over the heads of many people. Not on purpose, but probably because I have worked with electronics for so long, that I forget what it is like to just be starting out.
If I start to get too technical, please ask me to try and simplify my statements.
I need to take some pictures, to show how things are progressing. I may take one of the pulse generators that I built and mount it to the side that has the speaker, permanently wire for electrolysis use only, and use the 4 pin microphone cord to run to a foot switch. There are four connections on that jack that are not connected to ground, and so it is better suited for that operation. Since the circuit will now be inside the unit, power, ground and signal locations are easily available.
I was thinking initially that I would use the volume control, but I want to look into possibly using the Rf and Squelch control for the pulse generator. I need to figure out how to remove the knobs and the front of the chassis, so that I can get to the parts easier.
If I wish to try and emulate the Apilus synchro modality, I need to use two different pulse generators and key only when both are either positive or negative depending on how I choose to drive the transmitter. One pulse generator would continually produce fast pulses, while the other would set the overall duration length. thus one can have hundreds of very quick pulses during one cycle of the second pulse generator that is triggered by the foot switch. One knob would control the number of pulses in a given time period, and the other which is triggered would set the overall duration length of time. So the two knobs together like the RF and Squelch controls may work well for those functions.
Am I getting too technical. I am trying to keep things simple. Pictures obviously will help. Maybe I can make a picture, print it out and label the picture and then scan it into the computer in order to post. Can I assume that anyone attempting this project would know how to solder?
After this is done, I want to proceed with making an adjustable power supply. I will probably build that conversion into the power supply with a third lead to power just the final stage. If I put it within the CB, it would cut the voltage down for the final transistor by about 1.5 volts and maximum power would not be available without more modifications. Unless I went to the trouble to make a DC to DC conversion which is more complicated that I wanted to get into for this project. By building the adjustable supply withing the power supply, I can tap the voltage before it is regulated to 13.5 volts and can actually make it something like 5-20 volts on the final stage, and still keep the rest of the unit stabilized at 13.5vdc.
I could really use your knowledge of previous epilators. As I do not have that experience in my knowledge bank.

This is awesome! I just wanted to say that as a fellow electronic geek! I look forward to your updates. <3 MJoy

Marthajoy, I also look forward to your updates! I can’t wait to build an unit myself… Thank you!

Sorry for the slow-ness of any updates. I have been under the weather for the last week or so. Hopefully, I will return to full health again shortly. At least it does not appear to be pneumonia. I will soon hopefully be feeling well enough to resume this project. I do appreciate hearing from others interested in this little project that I have undertaken.
I will make note, that I have used the CB without modification on myself, and it does work. The down side is that it is so fast, the manually, the tendancy is to overtreatment and taking a week or two for skin to return to normal. That is with keying the microphone as fast as possible manually. I have found the keying circuit works well, using a 10 Microfarad cap for C and a 10 Kohm pot for pulse duration, That would allow adjustment of time from 1/10000 sec to about 1/10 sec. The down side is that I get a pulse both when depressing the foot switch and releasing it. I am considering a second circuit used to trigger th CD4013. I have a schematic for a 555 timer chip that should work.
I am also considering using a couple of Nand gates to form a multivibrator so that pulse width/ratio can also be adjusted.
The CB certainly has the power to perform hair removal, just experiementing to find the cheapest-easiest - safe way to accomplish what is needed.
But to be honest with everyone, this last week has not accomplished a thing as I have really not felt well.

Anyone Interested:
I have posted some changes to the website. Namely, I believe that I have a fix for the Foot Switch problem and also have decided on a circuit for the Variable Power Supply to be able to adjust the power output.
I have also included a circuit that will allow for multiple pulses in a given overall timing period. I am making some changes to the timing circuits as I have found that the Squelch and the Sensitivity controls are 40K ohms instead of the 10K ohms that I thought they were. With C being equal to 10 Microfarads the longest pulse would be about 0.4 seconds. If I make it 20 microfarads it would become about 0.8 seconds. The more I lengthen the maximum timing period, the more critical adjustments will become. I will probably set the minimum timing period at something like 0.01 seconds. I plan on the 555 circuits timing to be much quicker than that and probably in the order of 0.005 seconds or less. That is a frequency of only 200 hz, so it is very low frequency for this chip.
Anyway, this is a bit of a progress report.

http://marthajoy7.clearwire.net/CBconversion/