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That is the total bandwidth of the filter. The following is not exact but close enough for me to see what was going on. I fed an audio signal into the mic input at 1000 Hz.? At 28 Mhz I was getting 5.5 watts out of a modified ubitx using? the better output transistors and several other modifications that have been made by others. From that point I moved the audio signal up and down to where the power dropped off to about 3.5 watts. With the bfo set to? 11.996.800 mhz the low end was 500 hz and the high end 1900 hz ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?11.996.600? ? ? ? ? ? ? ?low end was 600 hz and the high end 2100 hz ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?11.996.400? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 400 hz? ? ? ? ? ? ? ? ? ? ? ? ? ? ?1800 hz If the bfo is moved too close to the filter, the 'carrier' power will go up and reach about 5 to 10 milliwatts output. de ku4pt On Thu, May 24, 2018 at 6:17 PM, Robbie Robertson <robbie.robertson@...> wrote: Sorry to be such a novice, but is that 1600-1700 centered around a particular frequency? |
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Re: 6uH in BITX40 band pass filter?
#bitx40
My doubt is because the same pass filter of BITX40 should not have 6uH because the scheme says 40 turns on toroid T30-6. Apparently this does not affect you. On the other hand I thought it was a filter with a series tuned circuit but if you put 6uH in series with 100pF you get 6.497Mhz ...
Additionally Allison, this filter does not have variable capacitance. |
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Re: Power problem !!!
#ubitx
#ubitx-help
Please do not create a new topic for this every time you post.? I make it hard to provide answers
because we replied over in the other post. You are not alone. The problem is understood and people are working on it.? FOr now you can turn up RV1 if you need more power on 10M. Allison |
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Re: 6uH in BITX40 band pass filter?
#bitx40
LIke Arv said.? and if its low or high spreading to closing the turns will move the value some.
All you care is the frequency of resonance.? You can tweak the cap soem to make it work. Allison |
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Re: Raduino CAD Files
W3JDR ?
Thanks for sharing, this is somthing I would be interested in. I have a maple mini and it does have the 128k but the blue pills I have are C8's ?and are 64k . ?I have seen articles where the C8 ?chip was programmed with the option in the arduino for the 128k ?and it worked fine. I downloaded ?your files and with a quick look they look very nice. Again, thanks for sharing. 73's and have a great vacation . kn4ud -- Allen ?Merrell |
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Re: UBITX filter bandwidth
its easy enough to alter the capacitor values.? To what is a guess by anyone that answers
as your crystals may be different from someone else. Try lowering all of them by 15% and remeasuring.? You will find out how it goes. FYI 68 and 82 are standard values.? If you need odd non standard your take say a 56 and add a 15 on top to get 71 for an example.? When I say stack them SMT caps are easily stacked like bricks. The usual procedure to make a filter would have you measure all the crystals then grind on the result and it will predict a capacitor value and terminating resistance.? ?And usually when I do that I fixture it and measure it before stuffing it in a board. Allison |
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If you are operating at 7070khz, and you feed in an audio tone of 1000hz, the rig will output rf at 7071khz to give you an idea. The SSB filter operates at AF, but it is relative to where the oscillator is operating. Least thats the best sense I can make of it. If this reply seems off, I apologize, I am missing emails here and there from this thread. On Thu, May 24, 2018, 6:17 PM Robbie Robertson <robbie.robertson@...> wrote: Sorry to be such a novice, but is that 1600-1700 centered around a particular frequency? --
---------- N5WLF, Greggory (or my nickname, Ghericoan) General Class, Digital Radio Hobbyist |
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Re: 2 meter bitx possible?
Arv,
You have it nailed.? THe 2n3904 would have an effective gain of maybe 2. I've done a few and generally the RX side is easy for SSB. The base receiver and SSB generator side flies well enough to clone. The mixer from 2M to 45mhz IF needs to be better too.? Add a RX rf amp. The side from the relays over to the edge would have to be new and must use more costly parts to hits a 10W level (enough to be sporting on 2M).? It would not do AM or FM. About 90% of the design effort would be the TX amps and filters so they are either easily tuned or no-tune.? We are not talking a 100$ radio anymore.? ROM would be 295-400$ I can see why as 2M rigs make a good transverter radio for 432 and up into the microwaves. For that 3-5mW is enough and a pair of MAV-11s would do fine to that power and a MAR6 or 8 for the RX preamp.? FOr that power level its a cheap design. Save for I know of no one taking or making a list. Allison |
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UBITX filter bandwidth
Has anyone tried to increase the bandwidth of the ubitx filter ?? Mine is about 1650 Hz wide at the 3 ot 6 db points. I would like to get it to about 2 to 2.2 KHz wide.? I am thinking about reducing the 100 pf capacitors to around 60 to 80 pf.? From what little I know about the filters, this should widen it out some, but may cause other undesirable changes.
de ku4pt |
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I have made some rough measurments and found the filter to be about 1600 to 1700 Hz wide.? If one wants to just the digital then the BFO frequency can be moved about 200 to 300 Hz to get the power up at the? higher audio frequencies. ? On Thu, May 24, 2018 at 5:23 PM, Tim Gorman <tgorman2@...> wrote: This is because of how narrow the SSB filter is. Once you begin to move |
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This is because of how narrow the SSB filter is. Once you begin to move
out of the passband your power output will drop. The filter in the ubitx is pretty narrow. It's not surprising you see a drop-off after 1600hz. tim ab0wr On Thu, 24 May 2018 10:57:27 -0700 "Robbie Robertson" <robbie.robertson@...> wrote: I'm new to uBITX, but used to operating digital modes (including |
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Re: 6uH in BITX40 band pass filter?
#bitx40
?A? ldrich?I would use 41 turns to start with.? That way you can easily remove one turn if 41 turns is too much.? Arv? K7HKL _._ ? On Thu, May 24, 2018 at 3:04 PM, Aldrich Sarmiento <aldrich.sarmiento@...> wrote: Greetings, I'm about to start building a BITX40 with the dead bug style and I've noticed that the filter passes band indicates 6uH however 40 laps on a toroid T30-6 is 5.76uH, not 6 ... I mention this because in my toroids I have 5.8uH and if I give it one more lap I have 6.2uH. So, which one do I use? |
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Re: 2 meter bitx possible?
Ron W7HD As has been said before, the 2N3904 devices in a BITX are not going to get you on 2M with any usable power.? Several have suggested using a transverter driven by a BITX.? It might be possible to make a BITX work on 2M by building one with transistors that have much higher frequency gain characteristics.? That could involve using a different MOSFET or BJT device in the RF PA stage.? 2 Meters with a BITX is probably a significant design effort, resulting in something that would be different from the basic BITX designs for HF. Arv? K7HKL _._ On Thu, May 24, 2018 at 2:33 PM, w7hd.rh <w7hd.rh@...> wrote: Put me down for interest in 2M SSB! |
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Re: Don't discount the rotary encoder as being at issue
Mike? KC2WBV, and others... The rotary encoder apparently is a bit fragile.? All outputs (phase-A, phase-B, and the push-button switch can easily be damaged if 5 or 12 volts at any substantial current level is accidentally applied while the switch contacts are closed.? That said...your experience with the encoder seems to match what some others have said recently.? Not yet sure if the problem is related to build instructions or to the encoders themselves.? It might be interesting if one of the bad encoders could be opened to see just what is going wrong with them. Arv? K7HKL _._ On Thu, May 24, 2018 at 2:26 PM, Mike aka KC2WVB <rb5363@...> wrote: I had assembled both the UBitx and BitX40 last weekend. The 40 meter radio worked perfectly. The uBitX would not tune nor would it properly allow entering into the menu. I knew from testing the encoder that one side of rotary aspect was defective because it showed constant 4.68 volts dc but all else on the encoder seemed OK. I ordered 5 identical replacements for the encoder from Digi Key the night I assembled the radio. They just arrived today. While waiting for the encoder I was thinking the Raduino might be at issue too and was trying to find a replacement for it. I just installed the encoder and honestly I was geared to see no change but indeed that was the problem. The UBitX works perfectly now. I attached a picture showing the VFO is no longer stuck on 7.150 Mhz and you will have to trust me that pressing the shaft of the encoder provides all the menu features too. |
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6uH in BITX40 band pass filter?
#bitx40
Greetings, I'm about to start building a BITX40 with the dead bug style and I've noticed that the filter passes band indicates 6uH however 40 laps on a toroid T30-6 is 5.76uH, not 6 ... I mention this because in my toroids I have 5.8uH and if I give it one more lap I have 6.2uH. So, which one do I use?
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Re: Power problem !!!
#ubitx
#ubitx-help
Kalid Several persons have provided ways to increase power output at higher frequencies. Allison is presently working on additional ways to provide the same power output on all bands.? If you go to the group page and do a search for "power" or "output" or "increase power" you should find messages that address this work. There is also the question of power meter accuracy as one goes up in frequency. An Oscilloscope gives the most reliable measurement of power into a dummy load. A diode detector probe can provide relative RF volts into a dummy load and thus indicate power output difference between lower frequencies and higher frequencies.? Arv? K7HKL _._ On Thu, May 24, 2018 at 1:37 PM, ??? ?????? <hamad.kalid@...> wrote: Hello everyone i faced problem with power when I measure the power with swr meter i get less than 10 watt in low side band in ultra side band i get 6 watt on 20 meter but 10 meter i get 0.6 watt so it's normally if it's can I use the amplifier to amplify to 20 watt ?? |
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Re: Help, can't change frequencies.
Mike aka KC2WVB
Had similar issue. New encoder from Digi Key fixed the issue. On Fri, May 18, 2018, 10:10 PM <Kd4epg@...> wrote:
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Ghericoan
Robbie Robertson
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