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Re: Harmonic performance - SSB vs CW
Jerry
A pair of diodes from ground to +5 might keep the A6 input from getting killed. Same for the A0 to A2 inputs. I had the A6 input die very early and no known reason for it.? It?behaves like there is a 150 ohm resistor to ground.? Mine was one that when? first turned on it went to CWtx? with the 4.7K in place...? Short term solution was move key to A7 (software fix) and the resistor to A7. That is low on the priority list.? Allison |
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Re: Harmonic performance - SSB vs CW
Pretty much all the Nano pins that go to the external Raduino connectors
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could have a series 1k resistor and still function perfectly well.? A short to 12v would be 12v/1k=12ma max. Even 100 ohms could be enough to prevent damage. Would have saved an awful lot of people an awful lot of grief for?an additional cost of about $0.10. On the other hand, the uBitx is by far the simplest and easiest to understand all band HF rig I've seen.? ? It takes a particular mindset to achieve that. Jerry On Sun, Aug 5, 2018 at 07:41 AM, ajparent1/KB1GMX wrote:
Adding protection to input on the NANO would |
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Re: uBITX: new build
#ubitx
Hi Your case is from looking for case to fit 7 inch LCD th yu -----Original Message----- |
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Re: any tips for debugging RFI issue?
#ubitx-help
On Sun, Aug 05, 2018 at 07:43:28AM -0700, ajparent1/KB1GMX wrote:
Mike,Just make sure the eavestrough is well bonded. Oxides are wonderful diodes. Any metal you have available can be helpful!Indeed. AllisonDiane -- - db@... db@... |
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Re: any tips for debugging RFI issue?
#ubitx-help
Mike,
Putting the wire in what is likely an aluminum gutter made it longer and likely not a bad thing. Any metal you have available can be helpful! Allison |
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Re: Harmonic performance - SSB vs CW
Raj,
Its that capacitance and also common mode via the magnetic frame that compromises the filter. The best combo for inexpensive relays is input bus, switching, filters, switching, output bus. The idea is separate relays at opposing ends of the filters.? The relays can be 5V or 6V units wired in series.? I've done this before and with a good ground plane it easily exceeds the need. However it need to be done twice.? At the input of the amplifier its an easy task to eliminate a large amount of unwanted stuff.? ? Its easy to have wide tuning RX but limited bands TX that is clean then.? If we do not put square waves and wide band spurs into the amp it helps the IMD and reduces what we get out. Two things helpful to the unequipped is a simple SWR detector and a RF out detector. that and a few built in measuring points.? Adding protection to input on the NANO would prevent some pain seen. as well as relocating the 4.7K to the Raduino board. Allison |
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Re: One question only...
Lawrence Macionski
Hi All-
Since very few of us have spectrum analyzers, there are ways to reasonably verify you're transmit signal will slip under the "illegal" problem. My first and last OO notice came in 1966 - I was driving my 6V6 single tube CW transmitter tuned via a #47 pilot lamp and received a notice my 2nd harmonic was being heard 90 miles away. (7154 x 2= 14308) I found tuning my pi-network, I could easily reduce a lot of 2nd harmonics just by backing off a few watts. I wound up homebrewing an antenna tuner and all my problems were gone.. A telephone, a buddy and his receiver 2 miles away confirmed it. An antenna tuner at the transmitter is good for harmonic suppression. Don't forget that wattmeter.. even with a dummy load will show all kinds of power output - clean or dirty...Remember that Backing down a few watts, will never be heard on the other end of a QSO and can render a cleaner signal. If your going to strive for more power strive for a clean signal as well.. |
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Re: Harmonic performance - SSB vs CW
John,
Any of those I'd use at RF will not fit the board.? At over 5$ each its someone elses choice. I along with several other have found the layout of the board to be problematic.? So? just replacing relays is not a simple fix.? Sarcasm alert: If I say the problem is systemic will there be?a posting to replace the "systemic" with something better?? ;) Allison |
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Re: One question only...
Brian,
There is no FCC approval process for kits and home brew.? It is the Amateur radio operator to assure its compliance.?? There is enough question as to do all or some not meet the numbers to say the sample size for those known to have issues is small enough to be an uncertain. Allison |
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Humble suggestion future Ubitx versions
#ubitx
I offer this suggestion for what it's worth, and with full knowledge that I barely know what I'm talking about.
It seems that the issue of spurs above 20 meters has been a source of endless discussion and confusion...not to mention a great deal of headache for those trying to troubleshoot. I understand that Farhan wanted to keep this kit at around a hundred bucks.? But I would suggest biting the proverbial bullet and filtering for 10 meters.? Perhaps add a smidge of Mic gain as well, and calling it done.? So the price creeps up near 200 bucks.? That is still within the grasp of the kid mowing lawns...or the humble poor scooter mechanic like me ;-) Market it for 10 20 40 and 80 meters and it's still by far the most incredible deal to ever hit the ham radio world. I understand that this kit is for experimenters and consider myself amongst them, albeit as a beginner.? But the sheer popularity of it has inevitability drawn a lot of beginners who just want to get on air.? That's not a bad thing so it might just be easier to satisfy that niche as well. Loving my v3 ubitx and almost ready to take my general exam.? Thanks to Farhan and all the other contributors. |
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Re: One question only...
Gordon Gibby
¿ªÔÆÌåÓýLow pass filters?$4.60 ea if necessary ( I have one to use a bitx40 on 80)?Likely some simple series tuned ?filter would add enough additional dB all by itself. ?Variable cap, single section , tune most bands with one circuit. ? ?This is ham radio....
Gordon
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Re: Harmonic performance - SSB vs CW
¿ªÔÆÌåÓýYes¡ Si5351 should be on the main board. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jerry Gaffke via Groups.Io ? Going forward, I for one would be fine with plug-in LPF's on a rig in this price range. -- ¡_. _._ |
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Re: One question only...
Jack Purdum
Christopher: I kinda agree on one hand, and as much as I hated the code exam (Novice in 1954) and vowed I would never do CW again after I got my General (1955), but something changed after I retired. 1955-2009 was pretty much AM-SSB, but now I find I am really enjoying CW. That Farhan put both modes into the ?BITX is one thing that attracted me from the outset, when I bought the BITX-40. My goal was to provide an inexpensive means by which young hams on a lawn-mowing budget could get on the (HF) air. (Far too many get their Tech, buy an HT for 2M, and shortly thereafter drop out, and I understand that completely.) My first attempt to do something was the Forty-9er (QST, March, 2016). Alas, that was CW only and very few newcomers seem to be interested in CW, and that's a real shame...one step in the dumbed-down process. When I surveyed my club members, 87% said they wanted to learn CW. Yet, when I offered to teach a class, everyone's sock drawer suddenly needed rearranging. That said, the ?BITX still is a great avenue for someone to venture away from VHF/UHF into HF at a very reasonable cost. The stock ?BITX is what I call a "semi-kit" and any licensed ham should be able to put a stock version together. Ian and a host of others have collaborated to add a touch-screen (Nextion) display, but still shoehorn it into a Nano. Jim Sheldon and his group have taken it a step further by adding additional features, too. Our JackAl board also extends what the ?BITX can do. These extend the capability and functionality of the ?BITX and make it a better rig...but you don't have to. The point is, the ?BITX is a great entry-level rig for someone on a limited budget or as a second rig for portable work. However, it is also capable of being a learning device, too. Anyone who reads the posts here and explores ubitx.net is going to be a more effective user of the ?BITX. That's a good thing. At your next club meeting, look around. Mine's getting a little long in the tooth and, frankly, I don't have an effective plan to change that. Clearly, we need young blood in this hobby and, if cost is any barrier to entry, the ?BITX can be our ally, provided we "sell it" correctly. It's a semi-kit that almost anyone can put together, use, and learn from, and that should be how we view it. Jack, W8TEE
On Sunday, August 5, 2018, 3:15:54 AM EDT, Christopher Miller <djmalak2k6@...> wrote:
What I get out of this is sad. I was one of the last hams in the US to actually have to learn Morse code to be able to have HF privileges.?
To me it seems the hobby is so dumbed down that if you expect to buy an unfinished kit and want to treat it like a Kenwood you probably are in over your head. This from my understanding was grown out of a desire to in fact provide people in places and economic situations to be able to use hf.? Find a spectrum analyzer or a person who can if you want to build your own rig.? KF4FTR |
MadRadioModder
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