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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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Re: Help, can't change frequencies on uBitx
Mike aka KC2WVB
I had a similar issue and thought the Raduino might be an issue but a new encoder from Digi Key fixed the issue. On Sat, May 19, 2018, 12:02 PM <Kd4epg@...> wrote: Yes, it responds to the push button depression just fine... |
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Re: Encoder issue
Mike aka KC2WVB
New encoder arrived today. Replaced the old with the new and wala the UBitX works perfectly now. On Mon, May 21, 2018, 6:26 PM Mike aka KC2WVB <rb5363@...> wrote:
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Don't discount the rotary encoder as being at issue
Mike aka KC2WVB
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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JackAl board update
Jack Purdum
All:
We have finished the new set of Gerber files and will be sending those off today. Those new boards will be sent to our Beta testers for evaluation. We also know that there will be 13 pins brought out, of which 2 are analog pins. One pin is for Vbat, to supply power for the RTC if you use that feature. If you use the CW messaging feature, that requires 3 NO push button switches, which reduces the available pins to 9 with all features implemented. While we still have some software to add to the project, I still think you should have around 800K of flash and 200K of SRAM to use. While some people say they have over-clocked the controller, at 180MHz, we don't see the need. I don't see those parameters changing much. The 5" and 7" TFT displays are resistive touch and use the RA-8875 controller and the 4 wire SPI interface sold by BuyDisplay.com (ER-TFTM050-3 and ER-TFTM070-5). Most of the raw display management is on the graphics board. The connectors on JackAl are the 10 pin IDC type (e.g., eBay 282084089830). The board is based on the PJRC Teensy 3.8 and use the audio board from the same company. The final board size is 100x90mm. The common board parts are 1206 SMD's. All SMD parts (e.g., transistor, the Si5351, and other chips) are in place on the board. The connectors are not part of the board because we felt you may want to hang some "special stuff" on the rig. Al and I still feel we are probably 2 months away from distribution. Jack, W8TEE |
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Was: RF power chain mods and improvements.. IS: 45MHz IF Attenuation
Farhan,
The 45MHz filter slopes are much gentle than that at around 1dB, similar to Jerry's number.? Here is the.plot of the response: /g/BITX20/message/45675 73, John |
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Power problem !!!
#ubitx
#ubitx-help
??? ??????
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: JackAl Board Debut
Jack Purdum
I doubt it, or it would at least require some major work as our screens are 800x480 and use the RA8875 graphics controller. I slightly modified the Sumatoy touch screen library, so it you have one that works with that library, the odds improve somewhat. Jack, W8TEE
On Thursday, May 24, 2018, 1:02:36 PM EDT, Richard E Neese <kb3vgw@...> wrote:
will this board work with your firmware ? I was thinking with all the pinouts I can do alot |
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Re: Power of rf
#ubitx
#ubitx-help
small increase adjust RV1.? That increases all so go for about 10-11W on 80m and
see what you get on 10M.? It should improve but 4-5W is maximum. Allison |
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Re: 2 meter bitx possible?
the spectral purity issue is a red herring as you will need band pas filters anyway.
The real issue the entire transmit chain is unsuitable for 2M. Most of the parts are marginal at 30mhz.? Also you will want a preamp ahead of the receiver as is noise figure is fine for HF but poor for VHF weak signal work. It would make a good low power radio as a transverter TRX.? Since most commercial transverters only need a milliwattt or three the entire pre-driver, driver and finals could be deleted.? Allison |
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Re: RF power chain mods and improvements..
How did this conversation end up here when there is another that is on topic
for attenuation via filter? My self I'd not do it.? A DBM makes a fine attenuator just very the injection current. Also the ND6T attenuator could? work in place of RV1. Many ways to accomplish it but first we need to have enough gain to produce the power. Allison |
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