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Re: v3 v4 L5 L7 Mod
Iz
I am curious what components you used to replicate the 45 MHz LC filter, and exactly where you installed it in the v4?? I am too concerned about radiating stuff above 30 MHz (the PA and existing LPF should be fine).? It's two spurs not too many MHz away when using 10 or 12 meters that need at least 10-15 dB rejection in my unit.? I like the xtal filter as is so not anxious to convert mine completely to a v5.? all is well enough with it, until I want to do SSB on those upper bands.? 73 Curt |
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Re: How to get rid of Local FM broadcast stations
#ubitx
When I entered the hobby I had a PC active speakers and when turned on I was hearing FM broadcasts on 88-108mhz. Then I placed speakers and the circuitry in a metal box and FM stations disappeared. Use aluminum foil I'm case you have a plastic enclosure to see if this might help. Il 21/dic/2019 16:17, "Gavin" <gdesplin@...> ha scritto: I haven¡¯t solved this issue yet. I attached a ground wire to my EFHW antenna, and that didn¡¯t help. I pulled the lm386 chip out and it looked fine and I put it back in. I don¡¯t have any other rigs to confirm it¡¯s not my antenna. Nothing happens if I touch the extra coils of wire.? |
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Re: My uBitx V3 picks up local broadcast throughout the band
#v3
#ubitx-help
#ubitx
ONX:
? I should have been more clear. There is a LM7805 regulator in a large TO-220 case that sticks out from the "Raduino" board attached to the back of the LCD display. Solder a 100nF from each of the outer two leads to the center lead of the LM7805.? These regulators are high-gain devices and can oscillate. The onboard bypass capacitors in the kit are not always effective. My 7805 oscillated and caused apparent broadcast interference on a sporadic basis. Chuck w8mqw |
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Re: How to get rid of Local FM broadcast stations
#ubitx
I haven¡¯t solved this issue yet. I attached a ground wire to my EFHW antenna, and that didn¡¯t help. I pulled the lm386 chip out and it looked fine and I put it back in. I don¡¯t have any other rigs to confirm it¡¯s not my antenna. Nothing happens if I touch the extra coils of wire.?
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Re: My uBitx V3 picks up local broadcast throughout the band
#v3
#ubitx-help
#ubitx
First thing to try is to bypass each terminal of the 5-volt regulator on the Arduino board to ground with two 100nF.? (The regulator will oscillate and induce the broadcast images.)
Second, you may have to build a bandpass filter for the band of interest. Or use a T-network antenna tuner that is both a LP and HP filter. |
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Re: v3 v4 L5 L7 Mod
Raj, Iz, Jonas, Ashar
thank you for reply, nice to hear from you all.? I wouldn't be asking if I had a spectrum analyzer to make the measurement!? I do have the relay board from Gordon installed, my harmonics are fine - CW is fully compliant and I am okay on SSB through 17 meters.? This was confirmed using a club member's analyzer.? Next I tried installing, every which way possible, a second 45 MHz xtal filter stage.? It greatly reduced the CW output on 40m to under 2 watts - so I decided this wasn't good.? (I trust not every v4 does exactly this, but I know of at least one other nearby that does).? Next I tried an LC filter similar to v5 has, it did not squash the 40m as much, but did nothing to improve the spurious on 10 and 12 meters - strong spurs hugging the carrier on each side.? I obtained some shielded SMT inductors from coilcraft, with a Q around 70 at 45 MHz.? More square than the one's Raj used (with little notches in corners) - was difficult to install.? 10m beacon sensitivity is similar to what I had.? Okay I can try the 45 MHz filter again - if it does not wreck 40m CW (with the better shielded inductors at 45 MHz on the existing filter) I can trust it will do something against these spurs (and can confirm the loss isn't huge).? I have one doubt on these inductors, that the shielding was intended against a much lower frequency than 45 MHz - so hard to infer what they are doing - except they are a much smaller antenna presence than the T37-6 (?) inductors.? 73 Merry Christmas and other blessings, Curt WB8YYY |
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Re: seasons greetings
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On Dec 21, 2019, at 6:01 AM, Dave Dixon <wylyeguy2@...> wrote:
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Re: Need help with reloading original uBitX v4 software
Thanks Jack! On Sat, Dec 21, 2019 at 8:34 AM Jack, W8TEE via Groups.Io <jjpurdum=[email protected]> wrote:
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Re: How to get rid of Local FM broadcast stations
#ubitx
Hi Gavin,
Is this issue resolved ? I also have similar problem. Not sure what is the resolution. ( I have talked about it in a different post) I am from Bangalore / India and I have a uBitx v3 running v0.20 software. Kindly suggest a resolution. I am also working on all the suggestions provided above. Thanks in advance. 73 Vu3onx |
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Re: Need help with reloading original uBitX v4 software
Jack, W8TEE
Jim: See attached...I think that's what you need. The libraries are specified as part of the #include preprocessor directives and a quick glance showed nothing outside the standard IDE libraries. Jack, W8TEE
On Saturday, December 21, 2019, 12:40:03 AM EST, Jim WB2LHP in MI <jmarco1955@...> wrote:
Greetings to all. I need help reloading the original uBitX v4 software using the Arduino IDE. I'm getting many errors too numerous to list when I verify the sketch. Can someone tell me what libraries I need to load and if there is anything else I should be looking at? Thanks in advance. Jim WB2LHP
-- Jack, W8TEE |
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My uBitx V3 picks up local broadcast throughout the band
#v3
#ubitx-help
#ubitx
Hi Friends,
I am a new Ham from Bangalore India. I had purchased a uBitx in Jan 2018 from HF Signals.? But I had not assembled it. I recently assembled the uBitx and observed it has TDA 2822 problem. I got that changed with a LM386 by making my own adapter board. Now coming to the problem I am facing.. From starting I am facing a problem. What ever frequency I tune in, I hear local AM broadcast. I feel there are some conversations in the background but the local AM reception is overshadowing everything. The audio is also not very clear. Did any one face the same issue? When I boot up my uBitx I observe it shows v 0.20. I have basic knowledge in electronics. Could any one please help me how to troubleshoot this ? I am so interested to start my conversation in HF but this is putting my interest down :( Please help. Thanks in advance. 73. vu3onx? |
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Re: v3 v4 L5 L7 Mod
The key is to do the math. Here is how it works, consider transmitting at 14 mhz. To generate 14 mhz, we mix the 45mz if with 59 mhz local oscillator. Now, we see a spur at 31 mhz. As we tune up and transmit again, the spur moves DOWN! This points to that the local oscillator is being subtracted from a fix signal. If you do the math (59 + 31 = 90mhz), you known that the spur is because of a 90 mhz signal showing up. Now, disconnect the mixer from the 45 mhz if amp and you will notice that the if has a second harmonic at 90 mhz (it will always do). To strip it off, you need to place an LPF.? So, first, the maths shows what happened, second, we test the 45 mhz if and confirm the presence of 2nd harmonic at 90 mhz and finally measuring after the mod results in expectedly lower spurs. -f On Sat 21 Dec, 2019, 2:15 PM iz oos, <and2oosiz2@...> wrote:
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Re: v3 v4 L5 L7 Mod
To address the spurious the Farhan LC filter make more sense. I noticed (on an SDR receiver) the spurs were actually reduced. I know you have tried that and seemed to make no difference. I would insist on that route changing the LC configuration. The issue is the 90Mhz harmonics that generate the spur, if I remember it right. In any case for 10 and 12m I use also an external high pass filter that cleans everything in those bands. Il 21/dic/2019 09:11, "Jonas Sanamon" <sanamon@...> ha scritto:
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Re: v3 v4 L5 L7 Mod
Hi Curt, I've done that mod on my v3, and I cannot see any difference in the spuriouses/harmonics on any band on the spectrum analyzer. I haven't replaced the relays yet so I don't know if that makes a difference, but in my experience changing the 2 inductors to the SMD version alone is a waste of time. Best Regards, Jonas - SM4VEY Den fre 20 dec. 2019 kl 23:57 skrev Curt via Groups.Io <wb8yyy=[email protected]>: I am curious if anyone is getting compliant SSB spurious on the upper bands by only replacing these inductors with small shielded SMT ones as I just have?? It may be a while before I get to measure my unit with a spectrum analyzer, but I am so tempted to stop here for now while things are working (I have Gordon's relay board installed to address harmonics). ? |
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Re: v3 v4 L5 L7 Mod
Curt, Change the relays first..
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Raj At 21/12/2019, you wrote:
I am curious if anyone is getting compliant SSB spurious on the upper bands by only replacing these inductors with small shielded SMT ones as I just have? It may be a while before I get to measure my unit with a spectrum analyzer, but I am so tempted to stop here for now while things are working (I have Gordon's relay board installed to address harmonics). |
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v3 v4 L5 L7 Mod
I am curious if anyone is getting compliant SSB spurious on the upper bands by only replacing these inductors with small shielded SMT ones as I just have?? It may be a while before I get to measure my unit with a spectrum analyzer, but I am so tempted to stop here for now while things are working (I have Gordon's relay board installed to address harmonics). ?
A logical next step is to add either a xtal or LC filter at 45 MHz in the transmit path.? But I may defer this until I get some data. 73 Curt |
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Re: ubitx v6, refactored code
Vic WA4THR,
After I am happy with the tuning for the radio with the BFO value and other setting, I do use Memory manager to create hex file backup only. However, I never had much luck tuning the BFO and offset value for the Raduino crystal using Memory manager. I see you have mentioned about "typical" values, do you have any explanation or reason behind these values. I never understood the mystery "Master" calibration number also and how it is calculated. I am sure there must be some calculation to derive at these "Typical" values. Hope someone on this forum can explain or else it is like magic :) Anthony VU3JVX |
Raj vu2zap
Jim Sorenson
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