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What happened to the SkyWave 2879ABTC?
Hi,
On Wed, 19 Sep 2007 05:55:10 -0700, Telstar Electronics wrote: The SkyWave 2879ABTC was discontinued because of a poor profit margin. Raising the price was not an option? Cheers, __ Gregg |
VoiceMax Transceiver Speech Processor
Distortion is more than harmonic distortion.
If any output does not replicate the input in amplitude and frequency response, there is distortion ... period! If a 1 Vp-p pure sine wave swept between 300 Hz and 3000 Hz goes into a device and produces an output of 2 Vp-p pure sine wave between 300 Hz and 3000 Hz there is a uniform gain of 2 and NO distortion. If a 1 Vp-p pure sine wave swept between 300 Hz and 3000 Hz produces 2 Vp-p at 300 Hz, then rises to 2.5 Vp-p at 1000 Hz and further rises to 2.8 Vp-p at 3000 Hz, the signal is distorted! The output is NOT a constant multiplier of the input. Run the test I posted. Or run it against a spectrum analyzer. Or, simply admit the output does not replicate the input. Lack of replication, in amplitude, frequency response or internal non-linearity, is distortion. A-D is specifying harmonic distortion ONLY. Speech compression is the deliberate introduction of distortion [to provide some desired result] In the recording industry, when analog recording was the norm, the recording studio distorted the recorded signal by the addition of 'pre-emphasis'. That is shaping the frequency response to compensate for known frequency variations in the recording media. The playback electronics may have had 'de-emphasis', depending upon recording media, to remove the effects of pre-emphasis and media distortion so that the output replicated the input. That is controlled distortion to achieve a desired result. Speech compression in radio-telephony is intentional distortion to achieve a perceived desired result. In mathematical terms TD = THD + dA/dF + dA/dT + dA/dV + d(Af(F))/dF ... should I continue? TD = Total distortion THD = Total Harmonic Distortion dA/dF = Intentional Amplitude variation as a function of frequency dA/dT = Amplitude variation as a function of temperature dA/dV = Amplitude variation as a function of bias voltage [AKA common mode, bias effects] d(Af(F))/df = Amplitude and gain variations as a function of gain roll off of the active device [a function of device gain rolloff [AKA gain*bandwidth product]]. I can add some more terms if you like. As a Chief Engineer I know and understand exactly what I am stating. A speech compression circuit deliberately produces a dA/dF, a variation in gain as a function of frequency, to achieve an intended result. It is distortion! As a company advertising and marketing a device, you should be precise in your language or define your terms explicitly. As far as I'm concerned this topic is dead, the funeral has been held, and the grave has been covered. I have no need to defend myself. Deek Telstar Electronics wrote: On Sep 19, 12:58 pm, Deek wrote: I'm sure they will acknowledge that it introduces controlled distortion. I'm surprised at you... being a chief engineer and all... you should realize that in this audio application we're talking strictly about harmonic distortion. After all, that's what you can hear. In the Analog Devices datasheet (page2)... this is given for the SSM2166 as "Total Harmonic Distortion including internal chip noise" of typical 0.25%... and a maximum of 0.5%. These figures rival the finest audio equipment! www.telstar-electronics.com |
What happened to the SkyWave 2879ABTC?
The SkyWave 2879ABTC was discontinued because of a poor profit margin. We hated to do it... but with the temperature compensating biasing... and all the premium components and chassis... it was just too costly to manufacture. Why on earth would you put temperature compensating components into this product. As far as I know no other doorstop on the market uses them. |
VoiceMax
Wes Stewart wrote:
SNIPPED So a bandpass filter for example is a distortion generator? Absolutely! The output does NOT replicate the input. That is distortion! Your definition of distortion is limited to harmonic distortion. There are other forms of distortion that have been used throughout the industry for years. When the output does not faithfully replicate the input, including any gain factor, it is distortion. So, a bandpass filter absolutely introduces distortion when it is used to exclude components of a broad band of signals. Better tip off all of those BC stations and recording studios that are using equalizers. recording studios know exactly what they are doing. they are selectively distorting the audio to achieve a desired effect. See my other post on this topic. A brief course in Fourier transforms will convince you that a distorted sine wave signal is still a series of sine waves, the fundamental, the 2nd, 3rd, 4th harmonic, etc. The existence of those harmonics is by definition DISTORTION. I see. So a perfect sine wave run through a perfect clipper will generate a 2nd harmonic? In the general cse the distortion products for all frequency components have to be considered in the analysis. The coefficients for any one or more frequency components can have a zero value. A perfect sine wave running through a perfect clipper will produce a square wave that is harmonically an infinite series of odd valued frequency components. A device that cause an amplitude variation as a function of frequency does not replicate the input signal. By definition that is distortion [I naver stated that it is harmonic distortion. Your definition of distortion is incomplete.] |
VoiceMax
On Wed, 19 Sep 2007 22:00:37 -0400, Deek wrote:
Wes Stewart wrote: SNIPPED So a bandpass filter for example is a distortion generator? Absolutely! The output does NOT replicate the input. That is distortion! Your definition of distortion is limited to harmonic distortion. There are other forms of distortion that have been used throughout the industry for years. Don't put words in my mouth. I asked *you* whether *you* thought a BPF was a distortion generator. Now we know your position. Any device that doesn't have DC to daylight frequency response and a perfect, infinite headroom, linear transfer function causes distortion. Gotcha. When the output does not faithfully replicate the input, including any gain factor, it is distortion. So, a bandpass filter absolutely introduces distortion when it is used to exclude components of a broad band of signals. Better tip off all of those BC stations and recording studios that are using equalizers. recording studios know exactly what they are doing. they are selectively distorting the audio to achieve a desired effect. See my other post on this topic. Uh huh. So recording studio personnel know what they are doing, but when I said earlier: "Since the purpose of a communication system (unless you're just peddling hardware) is to communicate, then one has to look at the trade-off between distortion and intelligibility. If purposefully "distorting" the signal by frequency shaping, compression, clipping or any combination thereof improves the intelligibility at the other end of the circuit then "distortion" is a good thing, semantics aside." I didn't know what I'm talking about. Right? A brief course in Fourier transforms will convince you that a distorted sine wave signal is still a series of sine waves, the fundamental, the 2nd, 3rd, 4th harmonic, etc. The existence of those harmonics is by definition DISTORTION. And of course you believe that you are the only one in this discussion that understands Fourier transforms. I see. So a perfect sine wave run through a perfect clipper will generate a 2nd harmonic? In the general cse the distortion products for all frequency components have to be considered in the analysis. The coefficients for any one or more frequency components can have a zero value. Why are you slipping into the "general case" when everything else you have put forth is in absolute terms? A perfect sine wave running through a perfect clipper will produce a square wave that is harmonically an infinite series of odd valued frequency components. Which is different from "a series of sine waves, the fundamental, the 2nd, 3rd, 4th harmonic, etc." A device that cause an amplitude variation as a function of frequency does not replicate the input signal. By definition that is distortion [I naver stated that it is harmonic distortion. Your definition of distortion is incomplete.] You are "distorting" what I said, I never offered any definitions. |
What happened to the SkyWave 2879ABTC?
On Sep 19, 8:53 pm, wrote:
Why on earth would you put temperature compensating components into this product. As far as I know no other doorstop on the market uses them. Not temp compensating components... temp compensating bias. www.telstar-electronics.com |
VoiceMax
On Sep 19, 12:22 pm, wrote:
i do truly admire the way you have these clowns helpsing advertise your product My hat is off to you. Funny how it works that way... lol www.telstar-electronics.com |
What happened to the SkyWave 2879ABTC?
On Thu, 20 Sep 2007 02:54:33 -0700, Telstar Electronics
wrote: On Sep 19, 8:53 pm, wrote: Why on earth would you put temperature compensating components into this product. As far as I know no other doorstop on the market uses them. Not temp compensating components... temp compensating bias. www.telstar-electronics.com Oh...your bias is magical? It uses no components for compensation? I always suspected your design to be that of an imaginary nature. |
What happened to the SkyWave 2879ABTC?
On Sep 20, 3:03 pm, wrote:
Oh...your bias is magical? It uses no components for compensation? I always suspected your design to be that of an imaginary nature. Not magical... it used the base-emitter voltage drop of an MJE3055T (mounted directly to heat sink) to track with the 2SC2879 power transistors. Since it used a transistor with gain... it worked so much better than just a plain old diode on the sink for tracking. It worked fantastic... I was able to set set class AB bias ( I chose about 200Ma) on the power transistors... and hold +/-5% collector current changes from -40 to +100C heat sink temp during amp operation. www.telstar-electronics.com |
What happened to the SkyWave 2879ABTC?
On Thu, 20 Sep 2007 17:08:23 -0700, Telstar Electronics
wrote in . com: On Sep 20, 3:03 pm, wrote: Oh...your bias is magical? It uses no components for compensation? I always suspected your design to be that of an imaginary nature. Not magical... it used the base-emitter voltage drop of an MJE3055T (mounted directly to heat sink) to track with the 2SC2879 power transistors. Since it used a transistor with gain... it worked so much better than just a plain old diode on the sink for tracking. It worked fantastic... How well it works depends on how well you hacked the design from this link I posted (while pointing out some of the many problems with your earlier splatterbox): http://www.ifwtech.co.uk/g3sek/tr-bias/tr-bias1.htm I was able to set set class AB bias ( I chose about 200Ma) on the power transistors... and hold +/-5% collector current changes from -40 to +100C heat sink temp during amp operation. That's interesting. Previously you said your bias scheme can "hold the 500mA bias to 10% from -30 to +85C". It's funny how many times you have changed the specs. I especially enjoyed the time when you changed the power output specs three times in one week after you were caught fabricating them instead of actually measuring them. Oh well, such is the life of an internet-educated hack. But alas, there's still one unresolved issue here, Brian.... where's the schematic? |
What happened to the SkyWave 2879ABTC?
On Sep 20, 10:48 pm, Frank Gilliland
wrote: On Thu, 20 Sep 2007 17:08:23 -0700, Telstar Electronics wrote in . com: On Sep 20, 3:03 pm, wrote: Oh...your bias is magical? It uses no components for compensation? I always suspected your design to be that of an imaginary nature. Not magical... it used the base-emitter voltage drop of an MJE3055T (mounted directly to heat sink) to track with the 2SC2879 power transistors. Since it used a transistor with gain... it worked so much better than just a plain old diode on the sink for tracking. It worked fantastic... How well it works depends on how well you hacked the design from this link I posted (while pointing out some of the many problems with your earlier splatterbox): http://www.ifwtech.co.uk/g3sek/tr-bias/tr-bias1.htm I was able to set set class AB bias ( I chose about 200Ma) on the power transistors... and hold +/-5% collector current changes from -40 to +100C heat sink temp during amp operation. That's interesting. Previously you said your bias scheme can "hold the 500mA bias to 10% from -30 to +85C". It's funny how many times you have changed the specs. I especially enjoyed the time when you changed the power output specs three times in one week after you were caught fabricating them instead of actually measuring them. Oh well, such is the life of an internet-educated hack. But alas, there's still one unresolved issue here, Brian.... where's the schematic? Glad you're back Frank... your always good for a laugh. www.telstar-electronics.com |
Telstar Electronics VoiceMax IS GARBAGE!
On Sep 19, 11:42 am, Deek wrote:
I conclude that the VOICEMAX issue has died, has had the funeral and now should be buried. Those who advocate high distortion levels and poor quality signals can spend their $$$ and buy it. That's just what the average cber wants. Makes em think they got a "BIG RADIO". |
What happened to the SkyWave 2879ABTC?
On Fri, 21 Sep 2007 07:37:54 -0700, Telspam Electronics
wrote in .com: On Sep 20, 10:48 pm, Frank Gilliland wrote: On Thu, 20 Sep 2007 17:08:23 -0700, Telstar Electronics wrote in . com: On Sep 20, 3:03 pm, wrote: Oh...your bias is magical? It uses no components for compensation? I always suspected your design to be that of an imaginary nature. Not magical... it used the base-emitter voltage drop of an MJE3055T (mounted directly to heat sink) to track with the 2SC2879 power transistors. Since it used a transistor with gain... it worked so much better than just a plain old diode on the sink for tracking. It worked fantastic... How well it works depends on how well you hacked the design from this link I posted (while pointing out some of the many problems with your earlier splatterbox): http://www.ifwtech.co.uk/g3sek/tr-bias/tr-bias1.htm I was able to set set class AB bias ( I chose about 200Ma) on the power transistors... and hold +/-5% collector current changes from -40 to +100C heat sink temp during amp operation. That's interesting. Previously you said your bias scheme can "hold the 500mA bias to 10% from -30 to +85C". It's funny how many times you have changed the specs. I especially enjoyed the time when you changed the power output specs three times in one week after you were caught fabricating them instead of actually measuring them. Oh well, such is the life of an internet-educated hack. But alas, there's still one unresolved issue here, Brian.... where's the schematic? Glad you're back Frank... I never left, Brian. your always good for a laugh. I'm glad you're amused. But don't you think it's time for you to get a job and relieve the financial burden on your parents and the Illinois welfare system? If I lived in that state I would be outraged that you are leeching my hard-earned tax dollars, but I don't. I guess people over there prefer to coddle malingering basement-dwellers. You are certainly lucky to live in a place with such generous folks, Brian. Over here on the left coast you would have to support yourself with gainful employment. And I hope that gives you something else to laugh about, cause the thought of you actually working for your keep sure leaves -me- ROTFLMMFAO!!! BTW, where's that schematic? |
What happened to the SkyWave 2879ABTC?
On Sep 21, 11:45 pm, Frank Gilliland
wrote: On Fri, 21 Sep 2007 07:37:54 -0700, Telspam Electronics wrote in .com: On Sep 20, 10:48 pm, Frank Gilliland wrote: On Thu, 20 Sep 2007 17:08:23 -0700, Telstar Electronics wrote in . com: On Sep 20, 3:03 pm, wrote: Oh...your bias is magical? It uses no components for compensation? I always suspected your design to be that of an imaginary nature. Not magical... it used the base-emitter voltage drop of an MJE3055T (mounted directly to heat sink) to track with the 2SC2879 power transistors. Since it used a transistor with gain... it worked so much better than just a plain old diode on the sink for tracking. It worked fantastic... How well it works depends on how well you hacked the design from this link I posted (while pointing out some of the many problems with your earlier splatterbox): http://www.ifwtech.co.uk/g3sek/tr-bias/tr-bias1.htm I was able to set set class AB bias ( I chose about 200Ma) on the power transistors... and hold +/-5% collector current changes from -40 to +100C heat sink temp during amp operation. That's interesting. Previously you said your bias scheme can "hold the 500mA bias to 10% from -30 to +85C". It's funny how many times you have changed the specs. I especially enjoyed the time when you changed the power output specs three times in one week after you were caught fabricating them instead of actually measuring them. Oh well, such is the life of an internet-educated hack. But alas, there's still one unresolved issue here, Brian.... where's the schematic? Glad you're back Frank... I never left, Brian. your always good for a laugh. I'm glad you're amused. But don't you think it's time for you to get a job and relieve the financial burden on your parents and the Illinois welfare system? If I lived in that state I would be outraged that you are leeching my hard-earned tax dollars, but I don't. I guess people over there prefer to coddle malingering basement-dwellers. You are certainly lucky to live in a place with such generous folks, Brian. Over here on the left coast you would have to support yourself with gainful employment. And I hope that gives you something else to laugh about, cause the thought of you actually working for your keep sure leaves -me- ROTFLMMFAO!!! BTW, where's that schematic?- Hide quoted text - - Show quoted text - Keep up the amusing posts Frank... www.telstar-electronics.com |
What happened to the SkyWave 2879ABTC?
On Sep 20, 10:48 pm, Frank Gilliland
wrote: How well it works depends on how well you hacked the design from this link I posted (while pointing out some of the many problems with your earlier splatterbox): http://www.ifwtech.co.uk/g3sek/tr-bias/tr-bias1.htm This is the first time I've been to that link. The circuit he shows with the two transistors is similar to mine. My feeling is that his is needlessly more complex, but I'm sure it works. I also agree with his statements about the diode method used for tracking. That method works a little better than no tracking and is not worth the effort. This is because putting two diodes in parallel never works right. One always has a lower drop... and hogs. www.telstar-electronics.com |
What happened to the SkyWave 2879ABTC?
Telstar Electronics wrote:
... Keep up the amusing posts Frank... www.telstar-electronics.com Personally, I run a speech compressor. I doubt many of these idiots could install one; apparently, they can't afford to have the local "cb tweak" install if for them either. Local, I kill the speech compressor, it is only for DX. Frankly, it doesn't hurt my feelings they don't have one! evil grin Keep up the sales pitch--few will be disappointed if they purchase one ... Regards, JS |
Telstar Electronics VoiceMax IS GARBAGE!
cmdr buzz corey wrote:
... That's just what the average cber wants. Makes em think they got a "BIG RADIO". Well, that is certainly better than a "Big-Headed-Amateur-Wannabe!" Get mental help, the opportunity is still open to 'ya! JS |
What happened to the SkyWave 2879ABTC?
On Sep 22, 3:16 pm, John Smith wrote:
Personally, I run a speech compressor. I doubt many of these idiots could install one; apparently, they can't afford to have the local "cb tweak" install if for them either. Local, I kill the speech compressor, it is only for DX. Frankly, it doesn't hurt my feelings they don't have one! evil grin Keep up the sales pitch--few will be disappointed if they purchase one ... John... good to hear from someone who has some experience with processors. I'm curious about the one you have. Can you tell me about it? www.telstar-electrnoics.com |
What happened to the SkyWave 2879ABTC?
On Sat, 22 Sep 2007 08:26:46 -0700, Telstar Electronics
wrote in om: On Sep 20, 10:48 pm, Frank Gilliland wrote: How well it works depends on how well you hacked the design from this link I posted (while pointing out some of the many problems with your earlier splatterbox): http://www.ifwtech.co.uk/g3sek/tr-bias/tr-bias1.htm This is the first time I've been to that link. Yeah, bull****. I've posted it four times over the years, and I'm sure you've run across it in your quest for hackable designs. The circuit he shows with the two transistors is similar to mine. Gee, what a suprise. My feeling is that his is needlessly more complex, but I'm sure it works. Let's see -your- design, Brian. I also agree with his statements about the diode method used for tracking. That method works a little better than no tracking and is not worth the effort. Yet you used it in your previous amps. You even defended the design, which is when I posted the link above. It wasn't long afterwards that you came up with your last hack job. This is because putting two diodes in parallel never works right. One always has a lower drop... and hogs. I don't see two diodes in parallel. Time to lay off the sauce, Brian. |
What happened to the SkyWave 2879ABTC?
On Sep 23, 4:34 am, Frank Gilliland
wrote: I also agree with his statements about the diode method used for tracking. That method works a little better than no tracking and is not worth the effort. Yet you used it in your previous amps. You even defended the design, which is when I posted the link above. It wasn't long afterwards that you came up with your last hack job. This is because putting two diodes in parallel never works right. One always has a lower drop... and hogs. I don't see two diodes in parallel. Time to lay off the sauce, Brian. Frank... I didn't say the diode scheme didn't work... I said it didn't work well. Actaually, the Motorola RF Data Manual shows this scheme in many of their designs... so maybe you give them a call and let them know how foolish they are... lol But seriously, the diode thing isn't worth the trouble unless you are willing to hand-select components that go alaong with that circuit. Even then, it's certainly not the best method. By the way... the diode tracking scheme does try and use two diodes in parallel. Sorry you don't see that... but that's how it is... and why it doesn't work well. www.telstar-electronics.com |
What happened to the SkyWave 2879ABTC?
On Sun, 23 Sep 2007 06:06:02 -0700, Telspam Electronics
wrote in . com: On Sep 23, 4:34 am, Frank Gilliland wrote: I also agree with his statements about the diode method used for tracking. That method works a little better than no tracking and is not worth the effort. Yet you used it in your previous amps. You even defended the design, which is when I posted the link above. It wasn't long afterwards that you came up with your last hack job. This is because putting two diodes in parallel never works right. One always has a lower drop... and hogs. I don't see two diodes in parallel. Time to lay off the sauce, Brian. Frank... I didn't say the diode scheme didn't work... I said it didn't work well. Actaually, the Motorola RF Data Manual shows this scheme in many of their designs... so maybe you give them a call and let them know how foolish they are... lol But seriously, the diode thing isn't worth the trouble unless you are willing to hand-select components that go alaong with that circuit. Even then, it's certainly not the best method. By the way... the diode tracking scheme does try and use two diodes in parallel. Sorry you don't see that... but that's how it is... and why it doesn't work well. I checked the page again thinking maybe it changed, but I still don't see two diodes. Just one. What two diodes are -you- seeing, Brian? |
What happened to the SkyWave 2879ABTC?
On Sep 24, 4:35 am, Frank Gilliland
wrote: I checked the page again thinking maybe it changed, but I still don't see two diodes. Just one. What two diodes are -you- seeing, Brian?- Hide quoted text - You're kidding me right?... the external tracking diode (one) and the base-emitter diode of the power transistor (two). Got it? www.telstar-electronics.com |
What happened to the SkyWave 2879ABTC?
Telstar Electronics wrote:
On Sep 24, 4:35 am, Frank Gilliland wrote: I checked the page again thinking maybe it changed, but I still don't see two diodes. Just one. What two diodes are -you- seeing, Brian?- Hide quoted text - You're kidding me right?... the external tracking diode (one) and the base-emitter diode of the power transistor (two). Got it? www.telstar-electronics.com ==================================== What a totally useless dialogue on a topic not relevant to this NG Would you please find another outlet for your egos. Frank GM0CSZ / KN6WH |
What happened to the SkyWave 2879ABTC?
On Sep 24, 6:25 am, Highland Ham
wrote: What a totally useless dialogue on a topic not relevant to this NG Would you please find another outlet for your egos. Frank GM0CSZ / KN6WH Hmmm... a discussion about the biasing of an RF amplifier is not relevant to this NG huh? Find another outlet for your complaints... lol |
What happened to the SkyWave 2879ABTC?
Telstar Electronics wrote:
On Sep 24, 6:25 am, Highland Ham wrote: What a totally useless dialogue on a topic not relevant to this NG Would you please find another outlet for your egos. Frank GM0CSZ / KN6WH Hmmm... a discussion about the biasing of an RF amplifier is not relevant to this NG huh? Find another outlet for your complaints... lol Please quit cross posting this to 'rec.radio.amateur.homebrew'; this _clearly_ is not a homebrewing discussion. Regards, Michael |
What happened to the SkyWave 2879ABTC?
msg wrote:
... Hmmm... a discussion about the biasing of an RF amplifier is not relevant to this NG huh? Find another outlet for your complaints... lol Please quit cross posting this to 'rec.radio.amateur.homebrew'; this _clearly_ is not a homebrewing discussion. Regards, Michael Strange! Have you guys now taken up knitting and crocheting? Hmmm. I liked it better when you actually discussed electronic circuits! JS |
What happened to the SkyWave 2879ABTC?
On Mon, 24 Sep 2007 02:52:47 -0700, Telspam Electronics
wrote in .com: On Sep 24, 4:35 am, Frank Gilliland wrote: I checked the page again thinking maybe it changed, but I still don't see two diodes. Just one. What two diodes are -you- seeing, Brian?- Hide quoted text - You're kidding me right?... the external tracking diode (one) and the base-emitter diode of the power transistor (two). Got it? So you claim it doesn't work because one diode will "hog" the current? Well, that's the point! D1 "hogs" the current and establishes a fixed voltage for the base of TR1!!! But alas, it only works if your ground plane is 9 square feet....... So where's that schematic, Brian? |
What happened to the SkyWave 2879ABTC?
On Sep 24, 2:42 pm, Frank Gilliland
wrote: So you claim it doesn't work because one diode will "hog" the current? Well, that's the point! D1 "hogs" the current and establishes a fixed voltage for the base of TR1!!! As usual Frank you are missing the important point here. That point being that you can't simply parallel two diodes... and have them share currents. This would have to be done in order for any tracking between the two. The problem is that one diode will always turn on before the other... and take all current. Now I ask you... where is the sharing/ tracking in that scenario? The answer is: there is no sharing/ tracking... because one diode with the lowest drop will hog the entire current... and the other diode will be off. this is why the gentleman on the web page link that YOU provided says it that scheme works like crap. He's absolutely right! www.telstar-electronics.com |
What happened to the SkyWave 2879ABTC?
On Tue, 25 Sep 2007 05:43:22 -0700, Telspam Electronics
wrote in .com: On Sep 24, 2:42 pm, Frank Gilliland wrote: So you claim it doesn't work because one diode will "hog" the current? Well, that's the point! D1 "hogs" the current and establishes a fixed voltage for the base of TR1!!! As usual Frank you are missing the important point here. That point being that you can't simply parallel two diodes... and have them share currents. This would have to be done in order for any tracking between the two. The problem is that one diode will always turn on before the other... and take all current. Now I ask you... where is the sharing/ tracking in that scenario? The answer is: there is no sharing/ tracking... because one diode with the lowest drop will hog the entire current... and the other diode will be off. Amazing. Two major bungles within one month. First you couldn't recognize a simple voltage multiplier, and now you show that you can't even understand the basic principle of diode biasing of a transistor. this is why the gentleman on the web page link that YOU provided says it that scheme works like crap. He's absolutely right! Funny..... he gives a different explanation. BTW, where's that schematic, Brian? |
What happened to the SkyWave 2879ABTC?
On Sep 25, 8:42 am, Frank Gilliland
wrote: Amazing. Two major bungles within one month. First you couldn't recognize a simple voltage multiplier, and now you show that you can't even understand the basic principle of diode biasing of a transistor. Frank, again you resort to degrading statements in an attempt to shift the focus and avoid the topic. You have suceeded... end of conversation with you. www.telstar-electronics.com |
What happened to the SkyWave 2879ABTC?
On Tue, 25 Sep 2007 05:43:22 -0700, Telstar Electronics
wrote: |On Sep 24, 2:42 pm, Frank Gilliland |wrote: | So you claim it doesn't work because one diode will "hog" the current? | Well, that's the point! D1 "hogs" the current and establishes a fixed | voltage for the base of TR1!!! | |As usual Frank you are missing the important point here. That point |being that you can't simply parallel two diodes... and have them share |currents. This would have to be done in order for any tracking between |the two. The problem is that one diode will always turn on before the |other... and take all current. Now I ask you... where is the sharing/ |tracking in that scenario? The answer is: there is no sharing/ |tracking... because one diode with the lowest drop will hog the entire |current... and the other diode will be off. this is why the gentleman |on the web page link that YOU provided says it that scheme works like |crap. He's absolutely right! |www.telstar-electronics.com | |------------- Bovine excrement. Ever heard of equalizing of current through a series resistance? Often called a ballast resistor. Used quite often in power transistors where there are several base/emiter pn jumctions. james |
What happened to the SkyWave 2879ABTC?
On Tue, 25 Sep 2007 07:08:51 -0700, Telstar Electronics
wrote: |On Sep 25, 8:42 am, Frank Gilliland |wrote: | Amazing. Two major bungles within one month. First you couldn't | recognize a simple voltage multiplier, and now you show that you can't | even understand the basic principle of diode biasing of a transistor. | |Frank, again you resort to degrading statements in an attempt to shift |the focus and avoid the topic. |You have suceeded... end of conversation with you. |www.telstar-electronics.com |------------- No Brian He is quite on topic. You are failing to comprehend a very simple basic understanding of the biasing of a transistor. james |
What happened to the SkyWave 2879ABTC?
On Tue, 25 Sep 2007 07:08:51 -0700, Telspam Electronics
wrote in om: On Sep 25, 8:42 am, Frank Gilliland wrote: Amazing. Two major bungles within one month. First you couldn't recognize a simple voltage multiplier, and now you show that you can't even understand the basic principle of diode biasing of a transistor. Frank, again you resort to degrading statements in an attempt to shift the focus and avoid the topic. The topic is the concept of using a diode to bias a transistor, a concept understood by any first-year electronics student. But not you. The BE junction stays at or above quiescient current BECAUSE the diode is hogging the current. It even says that in the article (that you obviously didn't understand). Two diodes..... sheesh..... I'll bet you've never seen a Vbe curve, either. You have suceeded... end of conversation with you. Well, since that's the closest thing to an admission of ignorance that you are capable of, I'll take all nine square feet...... ROTFLMMFAO!!! |
What happened to the SkyWave 2879ABTC?
On Sep 25, 9:37 am, james wrote:
Bovine excrement. Ever heard of equalizing of current through a series resistance? Often called a ballast resistor. Used quite often in power transistors where there are several base/emiter pn jumctions. OK James... less not discuss ballasting... because that has no bearing in this particular discussion. Maybe you can tell us how the diode method of biasing shown at http://www.ifwtech.co.uk/g3sek/tr-bias/tr-bias1.htm (bad circuits section) works. And since you think that circuit works well. Please tell us why. www.telstar-electronics.com |
What happened to the SkyWave 2879ABTC?
On Tue, 25 Sep 2007 08:09:50 -0700, Telspam Electronics
wrote in . com: On Sep 25, 9:37 am, james wrote: Bovine excrement. Ever heard of equalizing of current through a series resistance? Often called a ballast resistor. Used quite often in power transistors where there are several base/emiter pn jumctions. OK James... less not discuss ballasting... because that has no bearing in this particular discussion. Maybe you can tell us how the diode method of biasing shown at http://www.ifwtech.co.uk/g3sek/tr-bias/tr-bias1.htm (bad circuits section) works. Holy ****..... Brian flunked first-year techie school!!!! |
What happened to the SkyWave 2879ABTC?
On Tue, 25 Sep 2007 08:09:50 -0700, Telstar Electronics
wrote: |On Sep 25, 9:37 am, james wrote: | Bovine excrement. Ever heard of equalizing of current through a series | resistance? Often called a ballast resistor. Used quite often in power | transistors where there are several base/emiter pn jumctions. | |OK James... less not discuss ballasting... because that has no bearing |in this particular discussion. Maybe you can tell us how the diode |method of biasing shown at http://www.ifwtech.co.uk/g3sek/tr-bias/tr-bias1.htm |(bad circuits section) works. And since you think that circuit works |well. Please tell us why. |www.telstar-electronics.com |------------ Actually quite simple if you understand nodal analysis. Per Kirchoff's Laws the total current leaving a node must equal the current entering a node. The particular node that is of interest is in bad circuit A, is the junction of VRI, D1 and the base of the transisitor. For DC analysis the cap is an open circuit and the RFC is essentially a short. The current through D1 is set by the value of VR1, the supply voltage and the internal pn junction of the diode. The voltage drop across D1 is determined by the current flowing through the diode. In turn this sets the Vbe voltage of the base/emmitter PN junction. The instantaineous base/emmiter current varies with RF drive level. Should this current exceed 1/10th the current through D1, then D1 starts to loose regulation. This is the basic workings of a shunt regulator. Any good first year tech should know this. For either circuits, bad A and B, to work properly, the D1 diode current should be ten times the peak instantaineous base current of the RF power transistor. This type of biasing is good for low power RF devices. When dealing with large power devices, ie in the 100W and more class, this is not a good bias as the wasted heat in VR1 and D1 is very inefficient and prone to failure. Also there is no protection should a voltage spike on the DC supply propogate through. Most bipolar RF device do not like more than about 4 VDC base/emmiter voltage. Both circuits have no provisions for limiting the bias voltage in such a manner to cause permanent damage to the base/emitter junction. james |
What happened to the SkyWave 2879ABTC?
On Tue, 25 Sep 2007 08:20:48 -0700, Frank Gilliland
wrote: |On Tue, 25 Sep 2007 08:09:50 -0700, Telspam Electronics wrote in .com: | |On Sep 25, 9:37 am, james wrote: | Bovine excrement. Ever heard of equalizing of current through a series | resistance? Often called a ballast resistor. Used quite often in power | transistors where there are several base/emiter pn jumctions. | |OK James... less not discuss ballasting... because that has no bearing |in this particular discussion. Maybe you can tell us how the diode |method of biasing shown at http://www.ifwtech.co.uk/g3sek/tr-bias/tr-bias1.htm |(bad circuits section) works. | | |Holy ****..... Brian flunked first-year techie school!!!! | |------------- I am not sure he got far enough to flunk first year. Maybe after teh first half of the first year. Yes he seems to not understand a basic shunt regulator circuit or Kirchoff's laws. james |
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