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Re: uBITX AGC - Adafruit TPA2016, A Success!
#ubitx
And the line for the header file:
void enableNoiseGate(boolean ng); |
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Re: uBITX AGC - Adafruit TPA2016, A Success!
#ubitx
Also, need to add this new function to Adafuit library after the existing enableChannel function:
// Turn on/off Nosie Gate
void Adafruit_TPA2016::enableNoiseGate(boolean ng) {
?
? uint8_t setup = read8(TPA2016_SETUP);
? if (ng)
? ? setup |= TPA2016_SETUP_NOISEGATE;
? else?
? ? setup &= ~TPA2016_SETUP_NOISEGATE;
??
? write8(TPA2016_SETUP, setup);
} |
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Re: uBITX AGC - Adafruit TPA2016, A Success!
#ubitx
/***
? VK4PLN's AGC Code. Adafruit TPA2016
Add call to setupTPA2016(); to main code setup() in ubitx_20 after initOscillators();
/
?
#include <Wire.h>
#include "Adafruit_TPA2016.h"
?
Adafruit_TPA2016 audioamp = Adafruit_TPA2016();
?
void setupTPA2016() {
??
? audioamp.begin();
? // See Datasheet page 22 for value -> dBV conversion table
//? Serial.println("Right off, Left On,");
? audioamp.enableChannel(false, true);
?
? // Noise Gate Threshold: Below this value, the AGC holds the gain to prevent breathing effects.
? //Select the threshold of the noise gate (1,4,10,20mV) (0-3)
//? Serial.println("Noise Gate Threshold,");
? //Disable NoiseGate, we want to hear everything, even weak signals....
? audioamp.enableNoiseGate(false);
? audioamp.setNoiseGateThreshold(0);
??
? // Fixed Gain: The normal gain of the device when the AGC is inactive.
? // The fixed gain is also the initial gain when the device comes out of shutdown mode or when the AGC is disabled.
? // value 6 seems to work ok... based on datasheet. Where gain is from -28 (dB) to 30 (dB)
// Serial.println("Setting Fixed Gain");
? audioamp.setGain(-12); //-27 is ok? -12 is too high local stations arnt clipped...
?
? ? // Compression Ratio: The relation between input and output voltage.
? // AGC can be TPA2016_AGC_OFF (no AGC) or
? //? TPA2016_AGC_2 (1:2 compression)
? //? TPA2016_AGC_4 (1:4 compression) * Datasheet - Voice
? //? TPA2016_AGC_8 (1:8 compression)
//? Serial.println("Setting AGC Compression");
? audioamp.setAGCCompression(TPA2016_AGC_8);
?
? // Limiter Level: The value that sets the maximum allowed output amplitude.
//? Serial.println("Setting Limit Level");
? audioamp.setLimitLevelOn();
? // or turn off with?
? //audioamp.setLimitLevelOff();
? audioamp.setLimitLevel(30);? // range from 0 (-6.5dBv) to 31 (9dBV) (8.5dBv(30) as per datasheet)
?
? //Maximum Gain: The gain at the lower end of the compression region
//? Serial.println("Setting AGC Max Gain (18-30db - (0-12)");
? audioamp.setAGCMaxGain(12);
?
? /*
? ?*? ?For voice systems the attack time should be in the 2-ms region, with a hang time of about 0.3 sec,
? ?*? ?followed by a gradual recovery time of up to 1 sec.?
? ?*? ?http://www.qsl.net/va3iul/Files/Automatic_Gain_Control.pdf
? ?*
? ?*/
??
? // See Datasheet page 23 for value -> ms conversion table
//? Serial.println("Setting AGC Attack (0.1-6.7ms - (0-63))");
? audioamp.setAttackControl(3);
??
? // See Datasheet page 24 for value -> ms conversion table
//? Serial.println("Setting AGC Hold (0.0137-0.8631ms - (1-63))");
? audioamp.setHoldControl(0);
??
? // See Datasheet page 24 for value -> ms conversion table
//? Serial.println("Setting AGC Release (0.0137-0.8631ms - (0-63))");
? audioamp.setReleaseControl(4);
} |
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Re: RD16HHF1 in the uBITX
#ubitx
Bill,
toggle quoted message
Show quoted text
We can make a power sense and feed the DC say 0-5V to an analog pin of the raduino and depending on the power level change the drive current of the VFO, I think we can do a crude(ish) power control. Keeping the drive pot at the max setting. I understand that Allison has implemented an AGC/ALC that works on RX/TX. Raj At 18/02/2018, you wrote: I had a couple of hours of spare time today so I started off my measuring the gain of the pre-drivers in the uBITx.. and sure enough, there is a lot of variation from 1.8-54 MHz (where I want mine to work).?? Substituting the RD15HVF1 (my choice of RF PA) into the circuit with no other changes gives results similar to what John saw.. but it is because of the pre-driver stages.?? I contemplated ways of compensating the drive with frequency but there isn?€?t a really good solution using reactive components because it causes some other non-desirable behavior (like a peak in drive at 21 MHz that is too high for the PA).?? I did land on a rather bruit force method that does work well¡ I removed RV1 (drive control) from the cirrcuit board and replaced it with a tiny board with three small relays and four 100 ohm 10 turn pots.?? The relays are controlled by the KT1, KT1, and KT3 drivers¡?? The short story is that now I have gain that is adjustable for essentially each of the bands (at least sets of bands that follow the LP filters).?? I?€?ve adjusted the drive so that the PA puts out the same power (+/- about 2 watts) across the entire frequency spectrum.?? I suppose this should have been an obvious answer, but I?€?m not fond of using relays for stuff like this even if they only draw milliwatts¡ |
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Re: RD16HHF1 in the uBITX
#ubitx
¿ªÔÆÌåÓýWell this is gonna be important when it comes to activating the tuner I¡¯m designing.? You won¡¯t want to tune under full power so this turns out to be a great way to decrease the power for tuning. ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: Like us on Facebook! ? Moderator ¨C North American QRO Yahoo Group. ? email:? bill@... ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Dave Bottom
Sent: Saturday, February 17, 2018 7:32 PM To: [email protected] Subject: Re: [BITX20] RD16HHF1 in the uBITX #ubitx ? It is interesting that Chris M0NKA does this with his mcHF SDR kit. ? It has a Max Pwr setting that is similar to uBITX on 80M (12W) but they have a calibrate setting for each band at 5W, and then can step it down to 2W, 1W, 0.5W (these are approximate based on 5W setting of drive level.) ? When I get back home (Orlando then Yuma Hamfest) ?I¡¯ll make some notes on how he¡¯s done this, as I was already contemplating doing this on the uBITX when I go to the RD16HHF1¡¯s. ? Dave WI6R
I had a couple of hours of spare time today so I started off my measuring the gain of the pre-drivers in the uBITx.. and sure enough, there is a lot of variation from 1.8-54 MHz (where I want mine to work).? Substituting the RD15HVF1 (my choice of RF PA) into the circuit with no other changes gives results similar to what John saw.. but it is because of the pre-driver stages.? I contemplated ways of compensating the drive with frequency but there isn¡¯t a really good solution using reactive components because it causes some other non-desirable behavior (like a peak in drive at 21 MHz that is too high for the PA).? I did land on a rather bruit force method that does work well¡ I removed RV1 (drive control) from the circuit board and replaced it with a tiny board with three small relays and four 100 ohm 10 turn pots.? The relays are controlled by the KT1, KT1, and KT3 drivers¡? The short story is that now I have gain that is adjustable for essentially each of the bands (at least sets of bands that follow the LP filters).? I¡¯ve adjusted the drive so that the PA puts out the same power (+/- about 2 watts) across the entire frequency spectrum.? I suppose this should have been an obvious answer, but I¡¯m not fond of using relays for stuff like this even if they only draw milliwatts¡ ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: Like us on Facebook! ? Moderator ¨C North American QRO Yahoo Group. ? email:? bill@... ? ? From: [email protected] [mailto:[email protected]] On Behalf Of John ? I have done a strait replacement of the IRF510s with RD16HHF1s.? ? Here are the before and after values I got. ? All tests done with uBitx VR1 drive level in the same position of approx 60% of range. ? 1. IRF510s and main board at 12.1V. PA idle current checked at 0.20A total (factory setting) so assume 100mA in each final.? (For info, Rx currents: 164mA no volume, about 209mA "normal" volume).? - At 7.1Mhz:? ?10W, total current: 1.79A, of which PA current: 1.31A, therefore main board current 0.48A - At 14.2Mhz: 5.5W, total current: 1.39A, of which PA current: 1.0A,? therefore main board current 0.39A - At 21.2Mhz: 2.2W, total current: 0.95A, of which PA current: 0.53A, therefore main board current 0.42A - At 28.1Mhz: 1.3W, total current: 0.95A, of which PA current: 0.53A, therefore main board current 0.42A ? ? 2. IRF510s with 16.5V, 13.8V for main board. PA total idle current checked at 0.21A.? (For info, Rx currents: 188mA no volume, about 230mA "normal" volume).? - At 7.1Mhz:? 19W, total current: 2.65A, of which PA current: 2.09A, therefore main board current 0.56A - At 14.2Mhz: 11W, total current: 2.20A, of which PA current: 1.80A, therefore main board current 0.40A - At 21.2Mhz: 5.5W, total current: 1.40A, of which PA current: 1.00A, therefore main board current 0.40A - At 28.1Mhz: 2.2W, total current: 1.02A, of which PA current: 0.60A, therefore main board current 0.42A ? ? I haven't found a definitive reference for the safe and optimum values of the RD16HHF1s idle bias current but it seems to range from 200 to 500mA. So I would not recommend long term usage of the 500mA bias I used for these measurements. I will reset mine to probably the 400-450mA value I read from some articles. ? 3. RD16HHF1s and main board at 12.1VDC, 250mA idle bias each (Total 0.5A PA idle current).? - At 7.1Mhz:? 10W,? PA current: 1.20A - At 14.2Mhz: 9W,? ?PA current: 1.21A - At 21.2Mhz: 4.5W, PA current: 0.65A - At 28.1Mhz: 5.5W, PA current: 0.95A ? ? 4. RD16HHF1s and main board at 12.1VDC, 500mA idle bias each (Total 1A PA idle current).? - At 7.1Mhz: 10W, PA current: 1.18A - At 14.2Mhz: 9W, PA current: 1.26A - At 21.2Mhz: 5W, PA current: 0.71A - At 28.1Mhz: 6W, PA current: 1.11A ? ? 5. RD16HHF1s and main board at 13.8VDC, 500mA idle bias each (Total 1A PA idle current).? - At 7.1Mhz:? 13.5W, PA current: 1.95A - At 14.2Mhz: 13.5W, PA current: 1.93A - At 21.2Mhz: 6W,? ? PA current: 1.38A - At 28.1Mhz: 9.5W,? PA current: 1.79A ? ? ? Interesting observations: ? A. The RD16HHF1 produces a much flatter power curver over frequency (in my device), although it shows a dip somewhere near the 15m band. ? B. The IRF510 can produce some nice power in the lower frequencies when increasing the PA supply voltage, but it comes at the price of a steep power drop at higher frequencies. ? C. The bias does not seem to influence the efficiency of the finals at full power with RD16HHF1, since biasing at 250 and 500mA produces essentially the same output for the same DC power input. Assuming distortion reduces with higher bias, can we assume a higher bias (within limits) is preferable? Any risk of thermal runaway? ? D. The board main current (which includes the current in the driving stages of the power amplifier) does not seem to change with frequency from 20m onwards. Is this because the gain is pretty constant? If so, most of the drop in power with increasing frequency seems to be in the IRF510s, supporting the results obtained with the RD16HHF1s. ? E. With the current uBitx PA circuit the RD16HHF1 seems limited in output, although not having the proper test equipment I can't say where the limitation occurs. ? F. When I increased the drive through VR1 I noticed that at around 40% for the lower frequencies and at around 60% for the top frequencies I get a compression effect and the output does not increase much more from there on. I left it at 60% and got a positive feedback on the voice quality on my first QSO on 40m. Therefore I assume that the compression/clipping is not significant at that level (but I can't measure the sprectral purity). ? ? So since my target was around 10W on 10m and 10 to 15W on 40m minimum I can say I have reached my goal just by changing the finals to RD16HHF1s and supplying the board with 13.8VDC (below the 15.2/15V stated in the respective datasheets of the RD16HHF1 and TDA2822). ? To replace the finals I simply cut the legs of the IRF510s about 3mm above the board and correspondingly cut and crossed over the drain and source pins of the RD16s to match, then soldered in place. ? It would be interesting to compare these results with others who performed the finals swap on the stock uBitx. ? Next is the installation of the TPA2016 audio amplifier with I2C controllable AGC. This is a lot of fun. ? All the best, ? 73, John (VK2ETA) ? <image003.jpg> ?
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Re: RD16HHF1 in the uBITX
#ubitx
¿ªÔÆÌåÓýIt¡¯s not the bias¡ it¡¯s the drive level. ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: Like us on Facebook! ? Moderator ¨C North American QRO Yahoo Group. ? email:? bill@... ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Karl Heinz Kremer, K5KHK ? How about using an I2C DAC, and then letting?the Raduino setting the bias based on what band and what output power is desired?? |
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Re: RD16HHF1 in the uBITX
#ubitx
¿ªÔÆÌåÓýTrouble is¡ it occurs at every stage so where do you put the gain equalization?? I made a couple of calculations and then swept the circuit and noticed that the PA ran away at 21 MHz so did not pursue that.? I¡¯m sure there is a way to do it but I only had a couple of hours to work on it. ? Another thing that one could do is use an AGC circuit fed back from the PA to the first driver stage to control the overall stage gain¡ but again that will take some simulating to get through. ? BTW name is Bill¡ ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: Like us on Facebook! ? Moderator ¨C North American QRO Yahoo Group. ? email:? bill@... ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Gordon Gibby
Sent: Saturday, February 17, 2018 6:54 PM To: [email protected] Subject: Re: [BITX20] RD16HHF1 in the uBITX #ubitx ? ?Dr. Schmidt -- no way to put some feedback into the circuit in some manner to stabilize the gain?? ? 1000 pf across the 22 ohm emitter resistors to have a 3db break at 7 MHz? ? ? From: [email protected] <[email protected]> on behalf of K9HZ <bill@...> ? I had a couple of hours of spare time today so I started off my measuring the gain of the pre-drivers in the uBITx.. and sure enough, there is a lot of variation from 1.8-54 MHz (where I want mine to work).? Substituting the RD15HVF1 (my choice of RF PA) into the circuit with no other changes gives results similar to what John saw.. but it is because of the pre-driver stages.? I contemplated ways of compensating the drive with frequency but there isn¡¯t a really good solution using reactive components because it causes some other non-desirable behavior (like a peak in drive at 21 MHz that is too high for the PA).? I did land on a rather bruit force method that does work well¡ I removed RV1 (drive control) from the circuit board and replaced it with a tiny board with three small relays and four 100 ohm 10 turn pots.? The relays are controlled by the KT1, KT1, and KT3 drivers¡? The short story is that now I have gain that is adjustable for essentially each of the bands (at least sets of bands that follow the LP filters).? I¡¯ve adjusted the drive so that the PA puts out the same power (+/- about 2 watts) across the entire frequency spectrum.? I suppose this should have been an obvious answer, but I¡¯m not fond of using relays for stuff like this even if they only draw milliwatts¡ ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: Like us on Facebook! ? Moderator ¨C North American QRO Yahoo Group. ? email:? bill@... ? ? From: [email protected] [mailto:[email protected]] On Behalf Of John ? I have done a strait replacement of the IRF510s with RD16HHF1s.? ? Here are the before and after values I got. ? All tests done with uBitx VR1 drive level in the same position of approx 60% of range. ? 1. IRF510s and main board at 12.1V. PA idle current checked at 0.20A total (factory setting) so assume 100mA in each final.? (For info, Rx currents: 164mA no volume, about 209mA "normal" volume).? - At 7.1Mhz:? ?10W, total current: 1.79A, of which PA current: 1.31A, therefore main board current 0.48A - At 14.2Mhz: 5.5W, total current: 1.39A, of which PA current: 1.0A,? therefore main board current 0.39A - At 21.2Mhz: 2.2W, total current: 0.95A, of which PA current: 0.53A, therefore main board current 0.42A - At 28.1Mhz: 1.3W, total current: 0.95A, of which PA current: 0.53A, therefore main board current 0.42A ? ? 2. IRF510s with 16.5V, 13.8V for main board. PA total idle current checked at 0.21A.? (For info, Rx currents: 188mA no volume, about 230mA "normal" volume).? - At 7.1Mhz:? 19W, total current: 2.65A, of which PA current: 2.09A, therefore main board current 0.56A - At 14.2Mhz: 11W, total current: 2.20A, of which PA current: 1.80A, therefore main board current 0.40A - At 21.2Mhz: 5.5W, total current: 1.40A, of which PA current: 1.00A, therefore main board current 0.40A - At 28.1Mhz: 2.2W, total current: 1.02A, of which PA current: 0.60A, therefore main board current 0.42A ? ? I haven't found a definitive reference for the safe and optimum values of the RD16HHF1s idle bias current but it seems to range from 200 to 500mA. So I would not recommend long term usage of the 500mA bias I used for these measurements. I will reset mine to probably the 400-450mA value I read from some articles. ? 3. RD16HHF1s and main board at 12.1VDC, 250mA idle bias each (Total 0.5A PA idle current).? - At 7.1Mhz:? 10W,? PA current: 1.20A - At 14.2Mhz: 9W,? ?PA current: 1.21A - At 21.2Mhz: 4.5W, PA current: 0.65A - At 28.1Mhz: 5.5W, PA current: 0.95A ? ? 4. RD16HHF1s and main board at 12.1VDC, 500mA idle bias each (Total 1A PA idle current).? - At 7.1Mhz: 10W, PA current: 1.18A - At 14.2Mhz: 9W, PA current: 1.26A - At 21.2Mhz: 5W, PA current: 0.71A - At 28.1Mhz: 6W, PA current: 1.11A ? ? 5. RD16HHF1s and main board at 13.8VDC, 500mA idle bias each (Total 1A PA idle current).? - At 7.1Mhz:? 13.5W, PA current: 1.95A - At 14.2Mhz: 13.5W, PA current: 1.93A - At 21.2Mhz: 6W,? ? PA current: 1.38A - At 28.1Mhz: 9.5W,? PA current: 1.79A ? ? ? Interesting observations: ? A. The RD16HHF1 produces a much flatter power curver over frequency (in my device), although it shows a dip somewhere near the 15m band. ? B. The IRF510 can produce some nice power in the lower frequencies when increasing the PA supply voltage, but it comes at the price of a steep power drop at higher frequencies. ? C. The bias does not seem to influence the efficiency of the finals at full power with RD16HHF1, since biasing at 250 and 500mA produces essentially the same output for the same DC power input. Assuming distortion reduces with higher bias, can we assume a higher bias (within limits) is preferable? Any risk of thermal runaway? ? D. The board main current (which includes the current in the driving stages of the power amplifier) does not seem to change with frequency from 20m onwards. Is this because the gain is pretty constant? If so, most of the drop in power with increasing frequency seems to be in the IRF510s, supporting the results obtained with the RD16HHF1s. ? E. With the current uBitx PA circuit the RD16HHF1 seems limited in output, although not having the proper test equipment I can't say where the limitation occurs. ? F. When I increased the drive through VR1 I noticed that at around 40% for the lower frequencies and at around 60% for the top frequencies I get a compression effect and the output does not increase much more from there on. I left it at 60% and got a positive feedback on the voice quality on my first QSO on 40m. Therefore I assume that the compression/clipping is not significant at that level (but I can't measure the sprectral purity). ? ? So since my target was around 10W on 10m and 10 to 15W on 40m minimum I can say I have reached my goal just by changing the finals to RD16HHF1s and supplying the board with 13.8VDC (below the 15.2/15V stated in the respective datasheets of the RD16HHF1 and TDA2822). ? To replace the finals I simply cut the legs of the IRF510s about 3mm above the board and correspondingly cut and crossed over the drain and source pins of the RD16s to match, then soldered in place. ? It would be interesting to compare these results with others who performed the finals swap on the stock uBitx. ? Next is the installation of the TPA2016 audio amplifier with I2C controllable AGC. This is a lot of fun. ? All the best, ? 73, John (VK2ETA) ? ?
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Re: RD16HHF1 in the uBITX
#ubitx
Gordon Gibby
¿ªÔÆÌåÓý?Dr. Schmidt -- no way to put some feedback into the circuit in some manner to stabilize the gain?? ? 1000 pf across the 22 ohm emitter resistors to have a 3db break at 7 MHz?
From: [email protected] <[email protected]> on behalf of K9HZ <bill@...>
Sent: Saturday, February 17, 2018 6:51 PM To: [email protected] Subject: Re: [BITX20] RD16HHF1 in the uBITX #ubitx ?
I had a couple of hours of spare time today so I started off my measuring the gain of the pre-drivers in the uBITx.. and sure enough, there is a lot of variation from 1.8-54 MHz (where I want mine to work).? Substituting the RD15HVF1 (my choice of RF PA) into the circuit with no other changes gives results similar to what John saw.. but it is because of the pre-driver stages.? I contemplated ways of compensating the drive with frequency but there isn¡¯t a really good solution using reactive components because it causes some other non-desirable behavior (like a peak in drive at 21 MHz that is too high for the PA).? I did land on a rather bruit force method that does work well¡ I removed RV1 (drive control) from the circuit board and replaced it with a tiny board with three small relays and four 100 ohm 10 turn pots.? The relays are controlled by the KT1, KT1, and KT3 drivers¡? The short story is that now I have gain that is adjustable for essentially each of the bands (at least sets of bands that follow the LP filters).? I¡¯ve adjusted the drive so that the PA puts out the same power (+/- about 2 watts) across the entire frequency spectrum.? I suppose this should have been an obvious answer, but I¡¯m not fond of using relays for stuff like this even if they only draw milliwatts¡ ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: Like us on Facebook! ? Moderator ¨C North American QRO Yahoo Group. ? email:? bill@... ? ? From: [email protected] [mailto:[email protected]]
On Behalf Of John ? I have done a strait replacement of the IRF510s with RD16HHF1s.? ? Here are the before and after values I got. ? All tests done with uBitx VR1 drive level in the same position of approx 60% of range. ? 1. IRF510s and main board at 12.1V. PA idle current checked at 0.20A total (factory setting) so assume 100mA in each final.? (For info, Rx currents: 164mA no volume, about 209mA "normal" volume).? - At 7.1Mhz:? ?10W, total current: 1.79A, of which PA current: 1.31A, therefore main board current 0.48A - At 14.2Mhz: 5.5W, total current: 1.39A, of which PA current: 1.0A,? therefore main board current 0.39A - At 21.2Mhz: 2.2W, total current: 0.95A, of which PA current: 0.53A, therefore main board current 0.42A - At 28.1Mhz: 1.3W, total current: 0.95A, of which PA current: 0.53A, therefore main board current 0.42A ? ? 2. IRF510s with 16.5V, 13.8V for main board. PA total idle current checked at 0.21A.? (For info, Rx currents: 188mA no volume, about 230mA "normal" volume).? - At 7.1Mhz:? 19W, total current: 2.65A, of which PA current: 2.09A, therefore main board current 0.56A - At 14.2Mhz: 11W, total current: 2.20A, of which PA current: 1.80A, therefore main board current 0.40A - At 21.2Mhz: 5.5W, total current: 1.40A, of which PA current: 1.00A, therefore main board current 0.40A - At 28.1Mhz: 2.2W, total current: 1.02A, of which PA current: 0.60A, therefore main board current 0.42A ? ? I haven't found a definitive reference for the safe and optimum values of the RD16HHF1s idle bias current but it seems to range from 200 to 500mA. So I would not recommend long term usage of the 500mA bias I used for these measurements. I will reset mine to probably the 400-450mA value I read from some articles. ? 3. RD16HHF1s and main board at 12.1VDC, 250mA idle bias each (Total 0.5A PA idle current).? - At 7.1Mhz:? 10W,? PA current: 1.20A - At 14.2Mhz: 9W,? ?PA current: 1.21A - At 21.2Mhz: 4.5W, PA current: 0.65A - At 28.1Mhz: 5.5W, PA current: 0.95A ? ? 4. RD16HHF1s and main board at 12.1VDC, 500mA idle bias each (Total 1A PA idle current).? - At 7.1Mhz: 10W, PA current: 1.18A - At 14.2Mhz: 9W, PA current: 1.26A - At 21.2Mhz: 5W, PA current: 0.71A - At 28.1Mhz: 6W, PA current: 1.11A ? ? 5. RD16HHF1s and main board at 13.8VDC, 500mA idle bias each (Total 1A PA idle current).? - At 7.1Mhz:? 13.5W, PA current: 1.95A - At 14.2Mhz: 13.5W, PA current: 1.93A - At 21.2Mhz: 6W,? ? PA current: 1.38A - At 28.1Mhz: 9.5W,? PA current: 1.79A ? ? ? Interesting observations: ? A. The RD16HHF1 produces a much flatter power curver over frequency (in my device), although it shows a dip somewhere near the 15m band. ? B. The IRF510 can produce some nice power in the lower frequencies when increasing the PA supply voltage, but it comes at the price of a steep power drop at higher frequencies. ? C. The bias does not seem to influence the efficiency of the finals at full power with RD16HHF1, since biasing at 250 and 500mA produces essentially the same output for the same DC power input. Assuming distortion reduces with higher bias, can we assume a higher bias (within limits) is preferable? Any risk of thermal runaway? ? D. The board main current (which includes the current in the driving stages of the power amplifier) does not seem to change with frequency from 20m onwards. Is this because the gain is pretty constant? If so, most of the drop in power with increasing frequency seems to be in the IRF510s, supporting the results obtained with the RD16HHF1s. ? E. With the current uBitx PA circuit the RD16HHF1 seems limited in output, although not having the proper test equipment I can't say where the limitation occurs. ? F. When I increased the drive through VR1 I noticed that at around 40% for the lower frequencies and at around 60% for the top frequencies I get a compression effect and the output does not increase much more from there on. I left it at 60% and got a positive feedback on the voice quality on my first QSO on 40m. Therefore I assume that the compression/clipping is not significant at that level (but I can't measure the sprectral purity). ? ? So since my target was around 10W on 10m and 10 to 15W on 40m minimum I can say I have reached my goal just by changing the finals to RD16HHF1s and supplying the board with 13.8VDC (below the 15.2/15V stated in the respective datasheets of the RD16HHF1 and TDA2822). ? To replace the finals I simply cut the legs of the IRF510s about 3mm above the board and correspondingly cut and crossed over the drain and source pins of the RD16s to match, then soldered in place. ? It would be interesting to compare these results with others who performed the finals swap on the stock uBitx. ? Next is the installation of the TPA2016 audio amplifier with I2C controllable AGC. This is a lot of fun. ? All the best, ? 73, John (VK2ETA) ?
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Re: RD16HHF1 in the uBITX
#ubitx
¿ªÔÆÌåÓýI had a couple of hours of spare time today so I started off my measuring the gain of the pre-drivers in the uBITx.. and sure enough, there is a lot of variation from 1.8-54 MHz (where I want mine to work).? Substituting the RD15HVF1 (my choice of RF PA) into the circuit with no other changes gives results similar to what John saw.. but it is because of the pre-driver stages.? I contemplated ways of compensating the drive with frequency but there isn¡¯t a really good solution using reactive components because it causes some other non-desirable behavior (like a peak in drive at 21 MHz that is too high for the PA).? I did land on a rather bruit force method that does work well¡ I removed RV1 (drive control) from the circuit board and replaced it with a tiny board with three small relays and four 100 ohm 10 turn pots.? The relays are controlled by the KT1, KT1, and KT3 drivers¡? The short story is that now I have gain that is adjustable for essentially each of the bands (at least sets of bands that follow the LP filters).? I¡¯ve adjusted the drive so that the PA puts out the same power (+/- about 2 watts) across the entire frequency spectrum.? I suppose this should have been an obvious answer, but I¡¯m not fond of using relays for stuff like this even if they only draw milliwatts¡ ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: Like us on Facebook! ? Moderator ¨C North American QRO Yahoo Group. ? email:? bill@... ? ? From: [email protected] [mailto:[email protected]] On Behalf Of John ? I have done a strait replacement of the IRF510s with RD16HHF1s.? ? Here are the before and after values I got. ? All tests done with uBitx VR1 drive level in the same position of approx 60% of range. ? 1. IRF510s and main board at 12.1V. PA idle current checked at 0.20A total (factory setting) so assume 100mA in each final.? (For info, Rx currents: 164mA no volume, about 209mA "normal" volume).? - At 7.1Mhz:? ?10W, total current: 1.79A, of which PA current: 1.31A, therefore main board current 0.48A - At 14.2Mhz: 5.5W, total current: 1.39A, of which PA current: 1.0A,? therefore main board current 0.39A - At 21.2Mhz: 2.2W, total current: 0.95A, of which PA current: 0.53A, therefore main board current 0.42A - At 28.1Mhz: 1.3W, total current: 0.95A, of which PA current: 0.53A, therefore main board current 0.42A ? ? 2. IRF510s with 16.5V, 13.8V for main board. PA total idle current checked at 0.21A.? (For info, Rx currents: 188mA no volume, about 230mA "normal" volume).? - At 7.1Mhz:? 19W, total current: 2.65A, of which PA current: 2.09A, therefore main board current 0.56A - At 14.2Mhz: 11W, total current: 2.20A, of which PA current: 1.80A, therefore main board current 0.40A - At 21.2Mhz: 5.5W, total current: 1.40A, of which PA current: 1.00A, therefore main board current 0.40A - At 28.1Mhz: 2.2W, total current: 1.02A, of which PA current: 0.60A, therefore main board current 0.42A ? ? I haven't found a definitive reference for the safe and optimum values of the RD16HHF1s idle bias current but it seems to range from 200 to 500mA. So I would not recommend long term usage of the 500mA bias I used for these measurements. I will reset mine to probably the 400-450mA value I read from some articles. ? 3. RD16HHF1s and main board at 12.1VDC, 250mA idle bias each (Total 0.5A PA idle current).? - At 7.1Mhz:? 10W,? PA current: 1.20A - At 14.2Mhz: 9W,? ?PA current: 1.21A - At 21.2Mhz: 4.5W, PA current: 0.65A - At 28.1Mhz: 5.5W, PA current: 0.95A ? ? 4. RD16HHF1s and main board at 12.1VDC, 500mA idle bias each (Total 1A PA idle current).? - At 7.1Mhz: 10W, PA current: 1.18A - At 14.2Mhz: 9W, PA current: 1.26A - At 21.2Mhz: 5W, PA current: 0.71A - At 28.1Mhz: 6W, PA current: 1.11A ? ? 5. RD16HHF1s and main board at 13.8VDC, 500mA idle bias each (Total 1A PA idle current).? - At 7.1Mhz:? 13.5W, PA current: 1.95A - At 14.2Mhz: 13.5W, PA current: 1.93A - At 21.2Mhz: 6W,? ? PA current: 1.38A - At 28.1Mhz: 9.5W,? PA current: 1.79A ? ? ? Interesting observations: ? A. The RD16HHF1 produces a much flatter power curver over frequency (in my device), although it shows a dip somewhere near the 15m band. ? B. The IRF510 can produce some nice power in the lower frequencies when increasing the PA supply voltage, but it comes at the price of a steep power drop at higher frequencies. ? C. The bias does not seem to influence the efficiency of the finals at full power with RD16HHF1, since biasing at 250 and 500mA produces essentially the same output for the same DC power input. Assuming distortion reduces with higher bias, can we assume a higher bias (within limits) is preferable? Any risk of thermal runaway? ? D. The board main current (which includes the current in the driving stages of the power amplifier) does not seem to change with frequency from 20m onwards. Is this because the gain is pretty constant? If so, most of the drop in power with increasing frequency seems to be in the IRF510s, supporting the results obtained with the RD16HHF1s. ? E. With the current uBitx PA circuit the RD16HHF1 seems limited in output, although not having the proper test equipment I can't say where the limitation occurs. ? F. When I increased the drive through VR1 I noticed that at around 40% for the lower frequencies and at around 60% for the top frequencies I get a compression effect and the output does not increase much more from there on. I left it at 60% and got a positive feedback on the voice quality on my first QSO on 40m. Therefore I assume that the compression/clipping is not significant at that level (but I can't measure the sprectral purity). ? ? So since my target was around 10W on 10m and 10 to 15W on 40m minimum I can say I have reached my goal just by changing the finals to RD16HHF1s and supplying the board with 13.8VDC (below the 15.2/15V stated in the respective datasheets of the RD16HHF1 and TDA2822). ? To replace the finals I simply cut the legs of the IRF510s about 3mm above the board and correspondingly cut and crossed over the drain and source pins of the RD16s to match, then soldered in place. ? It would be interesting to compare these results with others who performed the finals swap on the stock uBitx. ? Next is the installation of the TPA2016 audio amplifier with I2C controllable AGC. This is a lot of fun. ? All the best, ? 73, John (VK2ETA) ? |
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Re: BITX40: Allard's Firmware with Rotary Encoder?
Although not Allard's sketch, this has worked for me: I am also using polling (without the interrupts) on a replacement sketch for the uBITX although I haven't completed the menus and such, it still works much better than the original. Perhaps you can use portions. 73, ND6T
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Re: New ideas for the Audio TX/RX pop and PA output stage improvements on ubitx.net
¿ªÔÆÌåÓýYes that makes sense¡ ? The current through a capacitor is given by I=C*dV/dt so the average current over time is I=C*int[dV/dt]/t¡ For your example: let¡¯s use a 100pf capacitor in an 30 MHz circuit at 50 VRMS which is 140V P-P.? Iavg = 0.42 * 0.707 = 0.3 amps average.? Now the spec from that capacitor in your finding is 0.1% at 1 VRMS at 1MHZ which is 0.00028A * 0.707RMS *1000% = 0.2 Amps continuous at 30 MHz.? Yikes we are over by 50%!? Note that this DOES vary with capacitance¡ that¡¯s why the larger the capacitor, the more current capacity is needed. ? There are plenty of calculators on the internet to figure this out¡. Google ¡°capacitor Current Calculator¡±. ? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: Like us on Facebook! ? Moderator ¨C North American QRO Yahoo Group. ? email:? bill@... ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Jerry Gaffke via Groups.Io ?
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Re: top band ubitx
Great work. Looks like the heat sinks are direct connect like the originals ? Sorry if you've already mentioned this.
I'm going for mica insulated types because then I can use a huge heat sink covering the entire back of the radio. We did it for years and no reason to not do it. I have one heat sink that came with a thermal electric cooler. Might use it, but I also have others. |
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Re: New ideas for the Audio TX/RX pop and PA output stage improvements on ubitx.net
¿ªÔÆÌåÓýThe mistake that most people make in RF circuits is not paying attention to the current rating of the part.? Make sure your capacitor can handle the current for its service.? The voltage, size, and rating (eg NPO) etc. are the easy parts. ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton ¨C J68HZ Soufriere, St. Lucia W.I. Rent it: Like us on Facebook! ? Moderator ¨C North American QRO Yahoo Group. ? email:? bill@... ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Rob Snow ? I'm learning here.? I understand that a mica capacitor is the best type to use with RF from reading and they are the most stable. ? What would the impact be of using a polystyrene or ceramic capacitor in place of the 33pf?? I'm assuming you would see distortion, but I don't know. |
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Nick VK4PP
Raj vu2zap
K9HZ
Don, ND6T
Michael Shreeve