Here is the implementation of the TenTec variable filter in my TenTec Rebel. Looks easy and works great. Jim KH6SKY

#ubitxcw #cw #ssb

The kitsandparts.com multiPIG+ receiver used a variable 5 pole Cohn filter. I built and measured one of these and found that as designed the passband was initially rather poor as you tuned for larger

#ubitxcw #cw #ssb

I'll throw my weapon of choice into the pile: the NEScaf switched capacitive audio filter. From the description: It is more flexible than previous filters for QRP rigs. It has two panel-mounted contro

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Tentec in their older radios had that filter approach using varicaps. I was called a Jones filter {patent holder} and the design is also seen in the Elecraft K2 and there is on line (the 'net) a desig

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The SSB6.1 transceiver employs a tuneable SSB filter with tuning diodes in place of the capacitors in a min-loss configuration. The rig is a basic SA612-based design. https://www.qsl.net/yt2fsg/diykit

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I would like to thank everyone for the good contributions to the discussion. I now have many new ideas, which I will read in a quiet moment. But I am sure that I will build and measure a separate quar

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Karl This tunable xtal filter with varactors has a notable use beyond tentec, in the elecraft K2. Its schematic and complete manual are on line. I still enjoy my K2. It allows setting up 4 bandwidths

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Filter mod on my uBitx (uses existing 12 Mhz crystals)

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These are a variation of the min-loss cohn filters. As only the coupling capacitance is varied without varying the terminating impedance, we must expect high ripple at all setting except one. What doe

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@ DF9RU Hello dear OM, would you please have a look to Tasa's site : http://yu1lm.qrpradio.com/bp%20yu1lm.htm His tunable quartz filter also seems to meet your requirements. A friend of mine is buildi

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Hallo Karl-Heinz I also have studied about this Filter made from Quarz. (I also own a HB-1B) - and soon an assembled uBITX (end Nov back in HB9) I let them with the Quarz Filters in mind. First I buil

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Dear uBITX enthusiasts. recently my uBitx transceiver has been finished. I find this project ufb because it is an excellent learning platform for me. As with many others, a number of modifications are

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You are welcome! Just learning myself. Best regards, 73, Jim

#ubitx #calibration #ssb

Thanks Jim! Where were you three weeks ago? :) My experience exactly. Your straightforward post will really assist new builders, Dean KK4DAS

#ubitx #calibration #ssb

Symptom: SSB audio is unreadable. When tuning the VFO, SSB signals are heard "off-frequency" then the audio "goes away" as the frequency gets closer to the correct frequency. Solution: Perform the BFO

#ubitx #calibration #ssb

So there is a early draft users guide in the folders section with the following calibration steps. There may be better instructions in some other guide. I am way too lazy to do a complete search. User

#calibration #ssb

The fact that you have to turn into a higher frequency indicates the internals of the microbitX may be at too lower frequency but you will figure it out. Try anything, it will either get better or wor

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Dear Mr. Gordon Libby. It pains me to say this, and I hate to admit it publicly, but you are exactly correct. Hahahah Neverthelss, I for one, will take (and give) all the help I can get. My noggin is

#calibration #ssb

Q: I did tune to 10.000 - no tone. The tone is on 10.002.100 on my radio. So first step - what do I change to get the frequency to display accurately? A: when you tune to 10.002.1 you hear a signal on

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Well guys, this is going to give you a good chance to begin to understand more and more about Radio! If you don’t hear the tone until you are tuned 2kHz off, then yes your radio is a fair bit out of c

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