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Re: End Fed antennas w/ uBITX
#ubitx
Warren Allgyer
I have returned home from vacation and now have better access to some of my files. In March of this year I had an extensive email exchange with Bob Allison, WB1GCM and Joel Hallas, W1ZR, the authors of the 2016 review of the MyAntennas EFHW. I have supplied that full email exchange to Jerry and Allison but I have chosen not to post it here because of its size. In that exchange however were some data files that I would like to share with the group. These document the transformer losses in this system when properly terminated in a resistive load. In actual operation these losses would be the best case and would be experienced only when the antenna is a resonant multiple of a half wave. The losses when not terminated in a 2470 ohm resistive load, which would be the case if the antenna were used on any band other than the single resonant band, are far higher. On the order of 8 - 10 dB. ? VNA Reflection 2470 ohm.pdf
VNA Reflection 2470 ohm.pdf
VNA Transmission _ Back to Back.pdf
VNA Transmission _ Back to Back.pdf
SA Plot Back to Back.pdf
SA Plot Back to Back.pdf
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Re: Spurious RF at beginning of CW transmission in the uBitx
Hi Arv,
I have not played with the radio much on SSB but suspect that is probably the cause for the "BITX Click". Simply adding a diode in series with R66 (cathode toward C64) should fix the problem. It is important to note that the possibility of brief oscillation could occur in both the 12 and 45 MHz bidirectional IF amplifier stages because of the back feeding of power from C52 and C64 during RX-TX and TX-RX transitions. Diodes added in series with R52 and R66 should eliminate that possibility. The values of remaining bypass capacitors (0.1 uF) in the IF amplifiers and associated discharge paths should result in extremely short time constants and should not be an issue. Cheers and 73, Bob N1KW |
#bitx40help #calibration Calibrating and VFO and BFO with Osciloscope
#bitx40help
#calibration
Hello Folks, i bought an BITX40 v3 from?. I don't have any folks that can send signal with good quality transceiver to calibrate my bitx. I have an oscilloscope with frequency meter, and what I'm trying to do is to calibrate VFO and BFO (Mod from?) to proper frequencies. Please, provide me an information how can I do that operation properly, if I can do it at all. Regards, ?ukasz SP7WKY |
Re: RF out
Pic. a bit out of focus but possible to fit coax cable to the connector.?? Crimp the terminals by hand and solder as well.
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Advantage also that you can unplug the cable if you need to remove the PCB. On Tue, Jul 31, 2018 at 02:10 PM, Nick VK4PLN wrote:
Great idea, |
Re: uBITx V3 Stuck in Transmit
#ubitx
When you plug back the top connector the resistance should not change.
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Since the resistance is changing it means your key jack wiring is the problem. If you wired a stereo socket for a paddle and plugged in a mono plug then you will be shorting the middle connection.. and keying up the TX. For RX the key line must have 5V through the 4.7K.. if the voltage drops then the Nano will key up the TX. Check! Raj At 31-07-18, you wrote:
The plug on top of the Raduino. |
Re: uBITx V3 Stuck in Transmit
#ubitx
Rodger,
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Which is the "digital plug" that you pulled off ? Raj At 31-07-18, you wrote:
Hi Raj |
Anyone with a Raduino for the uBITX version3 for sale?
Rodger
Hello all
How can I get a new raduino for my uBITX version 3. I'm almost sure the one I received from India is stuffed and I don't think they sell it separately. Perhaps Ashhar Farhan, VU2ESE can let me now things to test on the board. The condition is it has the 4k7 resister across the blue and green digital connection, but it goes into CW TX as soon as it's booted. I've tried removing the raduino from the radio and it's the same condition. Tried reloading the sketch, same issue. Any help will be much appreciated. -- Kind Regards Rodger - ZL1RAH |
Re: uBITx V3 Stuck in Transmit
#ubitx
Rodger
Hi Raj
I checked for a short. When I pull the digital plug off and measure resistance between the blue and green wires, there is 4k7 there. When I plug it back into the digital port, the resistance is very small.(1k18) I'm not sure if there is something funny with that raduino board, but maybe. I have nothing to compare it to. Thanks for the help. -- Kind Regards Rodger - ZL1RAH |
Re: CW keyer issues#ubitxcw
¿ªÔÆÌåÓýMike you need to remove the 4.7K resistor from the tip and connect it to the blue wire. That will st your jack up for paddle operation. The 4.7k resistor set the keyer pin high which keeps it in receive. This input is an analog input that looks for variations in voltage to set different states, receive, transmit, TX dits, or TX dahs.Skip Davis, NC9O? On Jul 30, 2018, at 23:08, Mike Short <ai4ns.mike@...> wrote:
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Re: Spurious RF at beginning of CW transmission in the uBitx
Raj had a nice simple fix for the carrier burst on the Bitx40,
might be applicable to the uBitx:?? ? ??/g/BITX20/message/33707 ? ??/g/BITX20/message/33742 As I recall, there were a half dozen other fixes that worked. We've already mentioned delays in software as Allard has done for the Bitx40. |
Re: Nextion TFT
How does the Nextion display look in bright light, or the sunlight. 73 Ken VA3ABN On Mon, Jul 30, 2018, 10:59 AM Ken <chase8043@...> wrote:
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Re: Gamma-matching antenna tuner
hirosmb
¿ªÔÆÌåÓýAh, correction:I saw somewhere that spurious emission OF UBITX is at the level of -45dB toward the fundamental frequency. // hiro
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CW keyer issues#ubitxcw
Mike Short
I am having issues with the keyer.? I will only use paddles for CW. Tip is dit, I connected the 2.2k to it. The middle contact is dah, connected the 10k to it. Other ends of the resistors are soldered together with the blue wire. The 4.7k is connected to the dit, and them to the green. What did I do wrong? I only get dahs,?
-- Mike AI4NS |
Re: Gamma-matching antenna tuner
hirosmb
¿ªÔÆÌåÓýChristopher,I saw somewhere that spurious emission is at the level of -45dB toward the fundamental frequency. However, Japan¡¯s latest spurious regulation requires more than -50dB and so I started thinking about pi-match tuner or BPF. This doesn¡¯t mean that uBitx doesn¡¯t suppress good enough spur but it just means that Japan¡¯s regulation is a little tight, I suppose. // hiro, JJ1FXF
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Re: End Fed antennas w/ uBITX
#ubitx
John,
Two ways.... peel away the goop and see.? the 1:1 is obvious. The 1:9 if its really 1:9 put a 450ohm resistor (a 470 will do in a pinch) from the output terminal to the coax ground with short leads.? The use an antenna analyser if its 1:9 then he reflected SWR will be 1:1 or ver very close. The inductance can only tell you the number of turns of the trifilar bundle.? To get that you need the ferrite type and size and use one of the kits and parts calculators for that ferrite and do it by trial. IF expect between 6 and 9 turns of the triple wires. Did you look at the ERACHI End fed kit manual posted earlier today? it makes that 1:9 transformer. Allison |