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Allison, I'm afraid if you tested the way you described in your original post on this thread, you weren't testing for crosstalk.? I believe what you measured wasn't cross-talk at all, but rather

Hi; The paragraph description on modifying the Beofeng mic connections to the uBITX is vague. Can a schematic please posted a schematic diagram as to how the mods actually are done. 'Thank you '73

Great data Warren. Are you also going to replace the other 45MHz filter with the matching one you received ? Sure shows what all working together can accomplish........ Good Soup for everyone.? 73

Raj, Doesn't leaving R27 in place give you better impedance matching ? Did you try cutting the trace in between and just putting the filter between C22 and R27 ? 73 Kees K5BCQ

Sorry Bill.? I didn't mention that I do set it with the PTT switch, then exit the setup mode.? This set has exhibited this symptom since day 1.? I thought changing out the Arduino would have

Hi Bob, I do not see the part where you save the setting after you have set it. Press the push to talk button to save it while you are still in the calibration mode. Otherwise it does exactly as you

When the set is first powered on, there is a tinny, high frequency audio.? When you enter the setup mode and enter calibration, pressing the menu button, the audio is normal tone. Then I adjust the

Wow! Very nice work, Warren!!!! Extremely helpful for many, many people!! Cheers! Gordon

Warren, Try with both matched filters.. that should get further reduction. I don't have a pair right now.. Raj

Hi Sunil, Transformer isolation is VERY useful for eliminating ground loops and Galvanic isolation for the audio circuits. should you design a revised digital interface board provisions for installing

And finally, finally (for real this time) a pic of the filter in place. The center ground lead of the filter is not visible but it bend under the case and picks up the R13 ground.

Good work ! I have been using 3 to 31MHz as my span as you will see these dancing deverishes darting in and and out of the lower end of the spectrum. I got better results by replacing C22 with filter

And finally, here is a wider span showing 15 through 10 meters harmonic performance. My unit has the onboard filters completely removed and this scan was made with an external 30 MHz LPF plus the R27

It turns out I did have time for one pass of spur measurement. Here are screens for each of 17 through 10 meters. Conditions of the test: Audio input: 100 mVrms, 1.5 kHz tone. RV1 adjusted in each

Raj We may be talking "past" each other or I may not understand the intent. But as I see it the added filter is indeed a passband filter for the 45 MHz LSB/USB signal. Referring to the attached scan:

Glenn, The intention of the filter is not the passband. I wanted to get rid of all the HF 3-30MHz that was being picked up from messing with the mixer and BiDi amp. So a 45M30 say 30KHz filter may be

Gosh, I have received now the comment by Ray, so mine is a kind of repetition of it.

You measured the filter at 50ohm but the terminating impedances should have been 650ohm/3pf. I am not sure whether the impedance of the stock filter is similar and the matching in the Ubitx might be

the sweep at 50R is in relationship to the mod suggested in this thread, which I understand is a '50R' impedance area.? I swept it exactly the same as? Warren for comparisons sake only.. vk3pe

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