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Re: Transmit Output Power (CW)
#v5
Rob
your as-is numbers are not bad on CW.? (some of us would gladly trade board with you - actually mine is somewhat simpler - except I had an even larger dip on 40m, that I corrected with a capacitor change pointed out by Asshar).? remembering each S-unit on receive is approximately 6 dB - I would not myself want to change anything.? (if you really really want a flatter PA - you could possibly buy the 10 watt PA kit from QRP-Labs, and use it instead of this portion of the ubitx - but funny thing when we get good solar flux in 4-6 years from now - you might be using a uBitx v12 or a QSX v3 ....) SSB needs to be evaluated separately, using an audio oscillator as an input.? the SSB path uses the 45 MHz mixer 'as a mixer.'? CW is different because it puts a bias onto the mixer, and then leaks through a signal at the intended RF (no mixing!).? keep in mind the driver and PA are common to both CW and SSB - the overall behavior should track but you may experience different degrees of dip and peaking.? with the circuit board as is - you can only do so much with the overall behavior of the PA and tweaking of the driver frequency response.? you might work very hard to get a better measurement into your power meter on 40m that the operator on the other end will not even notice.? 73 Curt |
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Re: #v6 control settings for 12V fan
#v6
My experience with fans and uBITX.
Some fans are electrically noisy and can be heard through the audio. I used a squirrel cage fan that was the pits. So if your fan is noisy you might want it on when transmitting only. Since the fan? is cooling off a heat sink it makes sense to me to just run it at a low speed rather than complicate with a sensor or something. I have one that uses an 80 mm fan with big heat sinks and it never gets warm. Found a cat sitting on a morse key for a long period. All was well.? On the last one I put together I isolated the power transistors and bolted them to a 1x1x1/8 aluminum angle stock and riveted the angle stock to the back of the aluminum case. No heat no noise. Super reliable.? Between my wife and I we have 5 BITX radios. That said I would turn on the fan at maybe 45. Use your hand and see when you think it is too warm. You may have to turn it lower than you think it ideal to keep it from getting hot running a digital mode. They are neat modules we have one driving our chicken brooder pen. -- 73 Dave |
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Re: CW Filter
Hi Reg,
sounds great, as the uBitx lacks a good CW filter (the provided one is set for SSB, that is much too wide when chasing for DX stations listening up...about 1Khz, right in the audio response :( ). As you talked about the volume control, I wondered if the CW filter was compliant with any audio AGC one can have already add, that is connected? to the volume pot ? 73s -- Laurent F5FIE. |
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For Sale: uBITX V6
Bob WB8CAC
V6 for sale.? Unmodified, stock firmware, assembled (with cabinet), and calibrated.? I've made about a dozen CW contacts with it. No SSB contacts only listened to the SSB signal on a web SDR receiver.? I'm never going to get around to messing with it to make CW operation? "convenient." $175 shipped US.? Paypal accepted.? Bob? WB8CAC, currently@...
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Re: Transmit Output Power (CW)
#v5
Joe Puma
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On Mar 12, 2020, at 9:16 AM, Joe Puma via Groups.Io <kd2nfc@...> wrote:
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Re: Transmit Output Power (CW)
#v5
Joe Puma
¿ªÔÆÌåÓýThanks Evan. I have done the power mod on V3 and also used different sized bias resistors which worked better for my board. ?My power out on CW is slightly higher then on SSB and it¡¯s not because of the CW carrier. My emails are along the 331 emails as I was asking questions so I am familiar with Allison¡¯s mod and comments about the differences between power out on CW And SSB. I know if you¡¯re going to do the mod. It¡¯s best to test your SSB out and use the CW carrier.?Joe KD2NFC? On Mar 12, 2020, at 9:02 AM, Evan Hand <elhandjr@...> wrote:
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Re: Transmit Output Power (CW)
#v5
Joe,
To the best of my knowledge, the v5 boards have the upgrades in the sections prior to the first mixer (upgrading the 2n3904 to BFR93W) related to SSB performance.? The upgrades that are not done are in the driver and predriver stages where the 2n3904s are suggested to be replaced with 2n2222a or better devices.? Those sections are the same for both CW and SSB and can be modified for more consistent performance per Allison/KB1GMX in messages over a year ago.? The original work was done on the v3 and v4 boards, which then brought up the harmonics and spurs issues.? This lead to the v5 fixes that solved them through both redesign of the output filter sections of the board and the addition of a 45 MHz low pass filter between the 45 MHz IF stage and the first mixer T2.? The 40 meter power "dip" has not been addressed.? I believe that the v5 boards are not as bad as some of the prior boards.? I conjecture that one of the issues was incorrect turns or spacing of the 40 meter lpf inductors that seems to have reduced the problem, but not eliminate it. To get more information of what has been tried to balance power out across bands I would read through the 331 messages that start with this one from Allison: Message #49729 /g/BITX20/message/49729 There has not been a significant change to the uBitx in the stages from Q90 through the output lpf, so there is some opportunity to improve, though the output that Rob listed is not as bad as some that have been posted on this message board. All, Above are just suggestions, conjecture, and beliefs on my part.? Please take that into account and please excuse any errors or misconceptions on my part. 73 Evan AC9TU |
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Re: Transmit Output Power (CW)
#v5
Looking at the schematic for the V5, I understand that the way it works is that the CW key line (DC) is fed into mixer 1 along with the Clock #2 signal.? The output signal path from this is then through the 45 MHz low pass filter (I think that's what it is on the schematic) and then into the normal transmit power output chain through Q90.? Isn't that the same as CW?
Regardless, for testing it in SSB, could I use the tune output from a digimode program such as Fldigi? |
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Re: Transmit Output Power (CW)
#v5
Joe Puma
¿ªÔÆÌåÓýBecause CW and SSB use different output stages and the mod he¡¯s doing is for SSB. I, sure someone here can explain it better. ?If you don¡¯t want to use a varing whistle use a 1khz tone from your iPhone. (Youtube video). The uBitx is not like other radios. ?Joe KD2NFC On Mar 11, 2020, at 11:05 PM, Matthew Chambers NR0Q via Groups.Io <mchambers@...> wrote:
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Re: uBitx v6 Microphone
#v6
it was simply the feedback from the speaker back into the mic, i guess. by now, i guess you have also changed the calibration of your radio. trying to listen to an ssb on a nearby radio is quite useless. the radio will overload the the carrier will be very loud. the audio from the speaker of the receiving radio will burst into the mic and loop around creating squeals. - f? On Thu, Mar 12, 2020 at 11:57 AM Rene <rmvanb@...> wrote: Ok Mark, de ssb-signalen zijn goed, nu zonder licentie, ik luister on the bands, most 20 and 40 meters. The tone i hear is like the high tone you here when you start to caibrate, its much louder then my voice and if i disconnect the microphone and push on the key, then TX start to work and still the tone is there. It is also with dummyload and antenna... |
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Re: uBitx v6 Microphone
#v6
Rene
Ok Mark, de ssb-signalen zijn goed, nu zonder licentie, ik luister on the bands, most 20 and 40 meters. The tone i hear is like the high tone you here when you start to caibrate, its much louder then my voice and if i disconnect the microphone and push on the key, then TX start to work and still the tone is there. It is also with dummyload and antenna...
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Re: uBitx v6 Microphone
#v6
Rene
No, i don't use cw, but now the problem is even bigger? i tryed to calibrate again, but the am signals here are week and the ones there are, are next to each other. So i tryed yester day to calibrate again but seems not to work out. This afternoon i'll try again. Thanks for reply.
Greetz Rene |
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Re: Transmit Output Power (CW)
#v5
why? he already did the test with CW which will give the maximum power out vs a whistle which will vary and may have a complex signal component and reduce how much power you see on a non-peak reading meter. in radio shops we always test in either CW or FM for max power out, and then in AM to set the carrier level. Matthew Chambers, CBT, NR0Q Owner/Engineer M Chambers Communications Engineering LLC PO BOX 855, Moberly, MO 65270 Mobile (660)415-5620 On Wed, Mar 11, 2020 at 9:57 PM Joe Puma <kd2nfc@...> wrote:
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Re: Transmit Output Power (CW)
#v5
Joe Puma
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On Mar 11, 2020, at 10:13 PM, Rob French (KC4UPR) <kc4upr@...> wrote:
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Transmit Output Power (CW)
#v5
I've collected all my parts to do Allison's transmit chain modifications (BFR106, 2N2222, 11 ohm resistors...).? I'm ready to go... but I wanted to QC my output power first.? Now, I have noticed on 40 meters (where I spend most of my time), that the output power is low, so now that I finally have a power meter, I went ahead and tuned RV1 while transmitting into a dummy load.? I tuned RV1 to get 12W output on 3.500 MHz, and then checked the output power across the rest of the bands.? This is what I got... is this representative of what other people have seen?? I know I'd seen reports of crazy low output power (<1 W) on 10 meters, which I did NOT observe here, obviously.? (Note, all of these were done with CW.)
Any thoughts?? (a) Are these typical of what others have observed?? (b) What can I expect from the transmit modifications, relative to this?? Higher output on 30, 20, 17? Thanks! -Rob KC4UPR PS - Random aside.? So I am using KD8CEC firmware version 1.2.? I noticed something weird on 40 meters... If I tune to exactly 7.000.000 MHz, or lower, in the 40 meter band, I hear the T/R relay switch and the display indicates in CW transmit, but there's 0 W output power.? But if I tune to 7.000.010 or higher, it's fine.? It's kind of like it's enforcing transmit restrictions, except that the ONLY place that it seems to do this is on the bottom end of 40 meters!? I've tried to trace code behavior for the band limiting, and could not identify anything that would make this happen.? Has anyone else observed this??? |
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SVHFS 2020 Registration Through April 15th
Robin Midgett
SVHFS Conference 2020 Registration...The Clock Is Ticking Pre-registration is open through April 15, 2020. Please use the registration form on the conference web page ? The 2020 Southeastern VHF Society Conference will be held in Gainesville, Georgia on April 24-25, 2020. Gainesville, GA is approximately 60 miles north of Atlanta in EM84ch. It is about 1.5 miles from I-985.? The Ramada Inn, of Gainesville, Georgia is the conference hotel for the 2020 SVHFS Conference. The hotel is now taking reservations directly. To book your room, please see the or follow this information: The conference rate is $80 per night. To secure this rate, call the hotel directly at 770-531-0907. Do not call Ramada central reservations or book through the Ramada Website. ? Ramada Inn 400 E.E. Butler Parkway Gainesville, GA 30501 770-531-0907 N34.297420 / W083.8222475 ¨C Thanks, Robin Midgett K4IDC |
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Re: Sasquattch Stomp Reminder
Many Hams think that too. And, I generally manage to get help on 2 meters or 440 - all I ever hear on 11 is cursing and people trying to "stomp" on each other. With a good quarter wave vertical, even ground mounted, you are going to be better for DX than more power on a loaded whip. Alex Netherton On Wed, Mar 11, 2020 at 6:09 PM Wayne Leake <wayneleake@...> wrote:
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Alex Netherton, W5ALX Buncombe County NC, EM85ro |
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Re: Sasquattch Stomp Reminder
?Yes, if you lower the voltage to the finals, the power out drops. ?Contrary to what many (CBers) think, more power does not increase range anywhere near as much as a better antenna. ?I proved that back when I ran a full length whip, compared to shorter antennas. Performed some simple tests using a field strength meter in a unit that also had a signal generator. The full length performed the best both RX and TX. ?For the record, I was one of very few who had the license to legally repair and adjust all radios, not just CBS. ?Now, I have only used a CB when I was on the long trips when I moved here about 14 years ago. 2 meters helped at times, but not often. Wayne WA2YNE On Wed, Mar 11, 2020, 10:00 AM Mark Spohr <mhspohr@...> wrote: Doesn't the power decrease when you lower the voltage? |
_Dave_ AD0B
Alex Netherton