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Re: RF power chain mods and improvements..
followup and notes:
First this is not a problem for any band if one is using CW.? The method of generation for CW? makes this a non issue.? So CW on any band is fine. The LO for the 45 mhz conversion to output frequency is high side already.? Low side would be a real mess as it would fall into the passband when the VFO got to about 29mhz (20M band).? Lets not go there. FYI: Sideband inversion (USB//LSB) is done at the second conversion to 12mhz by using a 33 or 57mhz output from the oscillator.? This has no effect on the issue. Where the BFO is has little issue with this as well. Things that can help for those that want 15, 12, 10M? and that is external band pass filters. That means relays and logic so for tx only there are four conditions.? 15,12 or 10m filter, straight through depending on band or RX mode.?? Most tuners be there T or L types will not have enough "selectivity" as the generally run at low Q and are not tuned to reduce spurs.? Also antennas used like G5RV and similar radiate well in the mid 14-18mhz range where the spur is.? The game here is never let it out of the box. Keeping your audio drive in the reasonable range sounds good but how to you know you are or are not?? The question is not is it there but is it excessive. A mod to put narrow band pass filters for 15,12 and 10 would work with added switching as they are needed only for TX.? Their insertion loss will aggravate the existing problem of low power and would need more gain to overcome. An approach is moving the first IF to 60mhz or higher.? Its way out as the first?IF has to work there and 3904s are inadequate and available inexpensive filters may be an additional problem. An LC filter is lossy and requires tuning and this would complicate the no factory tuning feature of uBitx.?? It all goes back to the general problem of DBMs being easy and very good but also a conundrum? in three ports.? Any of the three post is and input or an output and? while we put two signals in for a third out that third one is present inside and can then? mix with the other two to get a whole new family of signals.? Only one solution is Pick or avoid those unwanted signals or a band pass filter to only allow the desired ones.? Seems to prove Nyquist was right. Allison |
Re: Nextion Display
Bo Barry
Anxious to join the movement. One caution or stumbling block I've found is the difficulty of adapting code for various display sizes.
I've only had limited luck rescaling the figures, but haven't learned enough to convert one. I have a 5" version but plan to get the enhanced smaller one like Ian's. I don't understand how someone has connected it to the ubitx. I just read that it can be used without the Nextion library, with just Arduino code. Going to try that way to start. Any help appreciated. I'm now a very old, very slow learner compared to my hotshot days! 73 Bo W4GHV since '54 |
Re: RF power chain mods and improvements..
Jerry,
Isn't the standard convention to use USB on 20m and up? At least that's how I have done it since the 60's. Wouldn't this help with the spurs? tim ab0wr On Sat, 02 Jun 2018 02:43:36 -0700 "Jerry Gaffke via Groups.Io" <jgaffke@...> wrote: Move to a high side VFO. |
Re: FLdigi
Bo Barry
Solved it yesterday. On my Raspberry pi ?at least. Trying on my PC today.
Using flrig along with fldigi. Even tho the version on the pi doesn't have the flrig option. I clicked the rigcat option and it worked great. I read that hamlib needed 2 stop bits but the code in the two firmware versions I have use only 1. I changed and recompiled but saw no change. Anxious to start using instead of tinkering and troubleshooting. ? Bo W4GHV? |
Re: Dead bitx 40
you may have to check load side after removing the 780 ?if there is a short, we need to find if the Arduino is causing? ?if so, because removal? of arduino is more difficult,? i would have a small cut in the 5V feed line to arduino and then check if the short is gone.? if it is gone, , perhaps you have to service arduino. Many of members advised how to replace an ardunio without damaging the main board. please try to read. all the best Regards MVS Sarma ? On Sat, Jun 2, 2018 at 6:24 PM, Avijit <vu3mvh@...> wrote:
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Re: Dead bitx 40
Is the 7805 getting hotter than it did when things worked?
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Carefully measure the voltage of the 5v pin out of the 7805 to ground. The 5v pin is on the top of the 7805, the pin nearest the blue contrast pot. You can use one of the Raduino corner mounting holes as ground. Do you see 5v there?? (I would guess you do.) Any idea what happened to the rig between when it did work and when it didn't work? There's a bunch of unused wires hanging off of the Raduino, did they possibly brush against random points o the main board?? (Best to tape the ends of those wires up, or remove those wires entirely by extracting the pins from the connector). Using a shortwave receiver in SSB mode (not AM), put the antenna near the DDS wire from Raduino to main board. With stock firmware, I believe the VFO is around 12-7.2 = 4.8mhz. But with Allards improved firmware, it may be there, or have moved to 12+7.2 = 19.2mhz. Can you hear that VFO carrier?? ? It's probably within 100khz of the stated frequency. My guess is that you won't hear the VFO. My best guess:?? A loose wire end from a Raduino connector brushed against 12v on the main board and fried the Nano on the Raduino.? So you won't find that VFO using the SW receiver. You could fix this by clipping out the old Nano and replacing it with one you buy locally. Or you could replace the entire Raduino. Do you have a scope? Jerry On Sat, Jun 2, 2018 at 05:54 am, Avijit wrote:
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Re: ?BITX Disable TC (use for CW training)
Or hack the firmware On Sat, 2 Jun 2018, 16:19 PE1GIJ, <info@...> wrote: Disconnect the power to the PA and only feed the logic as a kiss solution. |
Re: RF power chain mods and improvements..
Move to a high side VFO.
Can be done by just switching to USB mode. I believe all firmware to date uses a low side vfo, at 45mhz - OperatingFrequency. when in LSB mode. This was done so that the BFO was low side, to avoid interference with Nano oscillators. If that's an issue, I think it is easily tamed. Jerry |
Re: RF power chain mods and improvements..
Gordon Gibby
¿ªÔÆÌåÓýA lot of people use a T- type tuner to connect to their feedline; these might provide a bit of filtering of the lower undesired frequency.
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Re: FLdigi
which firmware are you using?? - f On Sat, Jun 2, 2018 at 10:41 AM, Dennis <dennis@...> wrote: I have wsjt-x working fine, but I can't transmit using FLdigi. Receive works ok. Could someone share their settings with me? |
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