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Re: Raduino question.
Vince Vielhaber
measured where, across what impedance?Typically my RF measurements are all at 50 ohms, but right now I can't say for certain that last nite's were. I'll have to double check when I get home. Also I need to correct something, my initial output was 4ma, not 2ma. Vince. -- Michigan VHF Corp. |
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Re: W8TEE TFT/ VFO DISPLAY BOARD BOARD
Jack Purdum
Roger: I'm in Italy, so do not have access to my system. The output from the VFO us taken from the header pins in the upper left corner.? (The square is available at the other end of the header.)? Supply 9-15V to the power input pins. The VFO output goes to the BITX40 VFO pins. Jack, W8TEE From: Rodger <rodger_hanson@...> To: [email protected] Sent: Monday, October 23, 2017 1:46 AM Subject: Re: [BITX20] W8TEE TFT/ VFO DISPLAY BOARD BOARD Hello Adrian I have just bought one of Jacks boards and busy building it up to connect to my bitx40 v3. I'm a little confused in the documentation as to how and what to connect to where when it comes to both boards. Can you give me a little rundown on how you connected your two together please. 73 de ZL1RAH - Rodger |
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Re: Raduino question.
Gordon Gibby
measured where, across what impedance?
thanks for the information!!! ________________________________________ From: [email protected] <[email protected]> on behalf of Vince Vielhaber <vev@...> Sent: Monday, October 23, 2017 1:10 PM To: [email protected] Subject: Re: [BITX20] Raduino question. The output level is also frequency dependent. I already knew this but needed some more concrete numbers so I did some testing last nite. At 7.5 MHz I was getting approx 2VRMS with the current set at 2ma (I was using your library, Jerry). At 35.5 MHz that level dropped to less than 0.25VRMS. In at attempt to minimize this, at various points added some code to increase the output at certain frequencies. The best I was able to get at 35.5 MHz was a little over 0.5VRMS with 8ma selected. Vince. Yes, but the si5351 gives a square wave. -- Michigan VHF Corp. |
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Re: Raduino question.
Vince Vielhaber
The output level is also frequency dependent. I already knew this but
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needed some more concrete numbers so I did some testing last nite. At 7.5 MHz I was getting approx 2VRMS with the current set at 2ma (I was using your library, Jerry). At 35.5 MHz that level dropped to less than 0.25VRMS. In at attempt to minimize this, at various points added some code to increase the output at certain frequencies. The best I was able to get at 35.5 MHz was a little over 0.5VRMS with 8ma selected. Vince. Yes, but the si5351 gives a square wave. --
Michigan VHF Corp. |
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Re: Raduino question.
Gordon Gibby
¿ªÔÆÌåÓý?I see where you are coming from........
but the DESIRED frequency is a sine wave.? ??
All that "other stuff" that makes it into a square wave?? ?Those are UNDESIRED freuencies.? ? (Fourier analysis).? ?
so......if you're interested in the power level of the 5 or 19 MHz signal itself, it would still be the sine wave component that you're interested in, not the square wave.? ?
But the difference, when squared is only a factor of 0.5 or 2.
Mind you, I know precious little about mixers.....but a lot about fourier.? ?
From: [email protected] <[email protected]> on behalf of Jerry Gaffke via Groups.Io <jgaffke@...>
Sent: Monday, October 23, 2017 1:01 PM To: [email protected] Subject: Re: [BITX20] Raduino question. ?
Yes, but the si5351 gives a square wave.
And the root-mean-square voltage of a square wave is half of the peak-to-peak voltage. From ? ?? "RMS is equal to the value of the??that would produce the same average power dissipation in a? Another thought: asking the si5351 to drive a 50 ohm load is asking a lot. There is only one pin going in for the 3.3v rail, so this would certainly aggravate any crosstalk between the three output buffers. The diode ring mixer wants to see a 50 ohm source impedance at the local oscllator input to avoid reflections there. Might be better off with an asymmetric resistor network there. Or an mmic buffer amp. And/or use multiple si5351 chips. Jerry On Mon, Oct 23, 2017 at 09:47 am, Gordon Gibby wrote:
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Re: Raduino question.
Yes, but the si5351 gives a square wave.
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And the root-mean-square voltage of a square wave is half of the peak-to-peak voltage. From ? ?? "RMS is equal to the value of the??that would produce the same average power dissipation in a? Another thought: asking the si5351 to drive a 50 ohm load is asking a lot. There is only one pin going in for the 3.3v rail, so this would certainly aggravate any crosstalk between the three output buffers. The diode ring mixer wants to see a 50 ohm source impedance at the local oscllator input to avoid reflections there. Might be better off with an asymmetric resistor network there. Or an mmic buffer amp. And/or use multiple si5351 chips. Jerry On Mon, Oct 23, 2017 at 09:47 am, Gordon Gibby wrote:
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Re: Raduino question.
Gordon Gibby
¿ªÔÆÌåÓýHi, I didn't follow all of that, but RMS for a sine wave is .707 times peak
Thanks for all that information about the signal levels!
Sent from my iPhone
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Re: Raduino question.
Probably could drive a level 7 mixer from the si5351 cmos outputs.
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Though I'm not entirely sure. Assume the si5351 truly does have a 50 ohm output impedance as per the datasheet, and is driving into that 50 ohms from rails between 3v and ground. ?(3.3v, but with some losses) The rms voltage is half of that (this is a square wave, not a sine wave). With a 50 ohm load resistor, the load sees half of that rms voltage. Farhan's ubitx 150/36/150 pi attenuator reduces it by 6db, which means the voltage swing gets halved again. Power is volts squared over ohms, ?so power to the diode ring is ? ((3v/8)**2)/50 = 0.0028 watts = 2.8mw? In dbm, that's 10*log10(2.8mw) = 4.47 dbm. So should be adequate for a level 3 mixer ?(wants 3dbm into the local oscillator port). And could drive a level 7 mixer if you hack that attenuator back to 3 db. If any of you RF guys see errors in this, do let me know. Jerry On Sat, Oct 21, 2017 at 05:54 pm, Jerry Gaffke wrote:
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Re: More questions
David
Hmm, could this be a switch bounce situation? Bounce - when the switch has a mechanical oscillation against the contact, like two pieces of metal banging together and the pushing away, then coming back, and pushing away until the bang energy diminishes and the metal stays in contact. In the old days, in the dark times when 300 baud ruled the land, when we put a switch on a digital i/o line we either had to write code that would sense if the switch was triggered, then set a look again flag but not take action, look at the switch again in say 100 or 200ms, and if it was still triggered take action. Alternatively we sometimes put in a single shot multi-vibrator for momentary or a flip-flop if not, which held the switch state once triggered. Then if the switch had bounce after first contact it would have no effect on the microprocessor as the first trigger was locked.?
Anyway, just some odd old neurons firing off. 73? |
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Re: BITX QSO Night, Sunday, October 22, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
John P
On Sun, Oct 22, 2017 at 10:53 pm, Francesca Wine wrote:
I had not heard anyone? in the past monrh on 7.277. I think the band is not as good at night.?It's certainly been pretty poor at night?here on the East coast. The only saving factor here is that we have more stations around as opposed to Nevada.?Saturday afternoon a friend of mine in the Phoenix area was listening to a?WebSDR in NE PA and emailed me to let me know that he was hearing someone on 7277 calling CQ for the NY QSO Party contest. I got on around 4:30PM and worked?10 stations all across NY from Buffalo to Long Island. Although most of those stations were running more than 5W I assume, I got 58 and 59 signal reports from all of them with my 5W and Mag Loop. Would there be any interest in having 2 meeting times on Sundays;?the usual 7PM time plus maybe 4PM (remembering we change the clocks in a couple of weeks)? ? -- John - WA2FZW |
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Re: W8TEE B40 real time clock connections
#w8tee
Jacks on vacation...might be a while before he responds.
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Re: Raduino question.
Gordon Gibby
¿ªÔÆÌåÓý?think you're off a decimal point there.... 2 mA into 50 ohms is 1/5 of a milliwatt so it wold not be 3dBm....
From: [email protected] <[email protected]> on behalf of Kelly Jack <kellyjack1968@...>
Sent: Monday, October 23, 2017 5:30 AM To: [email protected] Subject: Re: [BITX20] Raduino question. ?
this page indicates that setting the drive at 2ma equates to 3dbm into a 50ohms load.
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Re: BITX QSO Night, Sunday, October 22, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
Francesca Wine
I had not heard anyone? in the past monrh on 7.277. I think the band is not as good at night.? I talk? on 7186 at 8am pst everyday on the? Early bird net on my bitx 40. --
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I have ?bitx40 ?and completely wired up. get nice hiss when the volume up. display lights up only showing Raduino V1.01. ?frequency never shown, anyone have that problem? ?i think the software is not in the chip. Francesca W7LTG ? NV? |
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Re: W8TEE TFT/ VFO DISPLAY BOARD BOARD
Rodger
Hello Adrian
I have just bought one of Jacks boards and busy building it up to connect to my bitx40 v3. I'm a little confused in the documentation as to how and what to connect to where when it comes to both boards. Can you give me a little rundown on how you connected your two together please. 73 de ZL1RAH - Rodger |
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Re: More questions
Gary O'Neil
I¡¯ve been successful at reducing the H/W induced PTT carrier burst to ~ 6ms, and this is unchanged by Allard¡¯s carrier blanking code... (i.e. 75 ms of no carrier). What did change however; is that it now only occurs intermittently, perhaps 25% of the time, with direct keying of the PTT input. It does nothing in CW mode however, where it continues to burst for 6 ms, then blank an additional 9 ms before the start of the first CW element. This corrupts the first 20% of the first element (if a dit) at 20 WPM, and possibly not terribly noticeable in modest QRM/QRN. It is a bit annoying to know it is there and allowing it to go unchecked though.?It also inhibits it¡¯s CW utility much above 20 WPM.
Going back to Dave¡¯s first suggestion on this; I moved the blanking code into the checkCW function. It now keys cleanly and uncorrupted with just a 25 ms delay. I still haven¡¯t tried the BITX on SSB, and have no urgent need to do so, but for my use, I am now a happy camper. :-) ?OTOH... Had I not sped up the TX/RX switching speed, the burst likely would have bridged through the gap (between 6 and 15 ms post keydown) which I may have created by shortening the burst duration while not successfully eliminating it altogether. Putting all of this together though, brings me back to being in favor of Dave¡¯s suggestion of or¡¯ing the MIC PTT with PTT_SENSE, since this would replicate keying the transmitter as if in CW mode. It would appear reasonable to assume that if blanking of a short 6 ms burst in fast H/W for CW, unmodified hardware could be tamed by an arbitrary length blanking period in SSB mode, and 75 ms may work fine for those who have no need for CW very much above 16WPM.? The software is changing faster than I can learn C/C+/C++ and Arduino programming, so I haven¡¯t figured out how to hack the code to do this successfully yet. I¡¯m also not absolutely certain Dave¡¯s approach will work simply by wire or¡¯ing the H/W. PTT_SENSE needs to be detected early in the SSB PTT detection routine so that the clock can be shut down ahead of activating K1, and restart delayed until K2 is activated and all power supply changeover transients have settled. e.g. early in the checkCW function, the software could differentiate between keydown and Mic PTT using something like: if(PTT-SENSE && !TX/RX) { ? ?// Mic PTT activated and key or keyer input not detected.... SSB transmit mode requested. si5351bx_setfreq(2, 0); ? ? ? ? ?// turn off CLK2 digitalWrite(TX_RX, 1); ? ? ? ? ? // Activate relays
inTx = true; ? ? ? ? ? ? ? ? ? ? ? ? ? ?// Set transmit mode flag? } ... ... ... // And just prior to exiting the checkCW function delay(75); ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? // Wait for K1, K2, and power supplies to settle?
setFrequency(); ? ? ? ? ? ? ? ? ? ? ?// Restore CLK2... ?Transmit setup is complete, VFO, and carrier (if required), can be enabled. } This would ensure all of the hardware setup is stabilized, and be independent of transmit mode. Just my 2 cents.? 72 / 73 Gary, N3GO |
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Re: Bandpass filter
As a homebrewer, it is best to keep a set of outboard LPFs that can be swapped around or left connected to their antennas. You can make them as needed. - f On 23 Oct 2017 7:38 am, "Jerry Gaffke via Groups.Io" <jgaffke=[email protected]> wrote: Sounds to me like Ryan was asking whether this discussion somehow applies to the transmit LPF's. |
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Re: Nano on-board regulator...was: I made a mistake
I have tried several of the small switcher regulators, but in most cases I had to add additional filtering to reduce noise. When I have to run a Nano or pro-mini with more than about a 9V, I just feed it through several 1N4002 diodes in series to drop the applied voltage down to the 7-9 volt range. This makes the little regulator on the Nano or Pro-mini much happier.
-- DuWayne? KV4QB |
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Re: Bandpass filter
Sounds to me like Ryan was asking whether this discussion somehow applies to the transmit LPF's.
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And that Farhan is thinking only about receive. Jerry On Sun, Oct 22, 2017 at 06:11 pm, Ashhar Farhan wrote: Ryan, |
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Re: Quantum Indians
Thank you Bill for sharing a very educational video. I really enjoyed watching. Larry WA9DOH On Fri, Oct 20, 2017 at 6:46 PM, Bill Meara via Groups.Io <n2cqr@...> wrote:
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DuWayne Schmidlkofer
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