Great idea,
Do you think it makes a difference??
How about using coax instead for the normal wires?
Cheers
Nick, VK4PLN
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How does the Nextion display look in bright light, or the sunlight.
73
Ken VA3ABN
Hi Al
A few of us have the ubitx and bitx40. We had quite few people at the meeting, which is odd for the summer months. Anyways we have a few teens joining and decided we could do something they could use. In the next month we'll be coming with a plan and we do have a resident software guy.
Next buildathon news to come.
73 Ken
On Mon, Jul 30, 2018, 9:36 AM Al Duncan VE3RRD < ve3rrd@...> wrote: Hi Ken, our little builder group in Barrie has been focusing on the uBitx and the amazing firmware from Ian KD8CEC . A number of us also have the Bitx40 which works very well with the Allard PE1NWL firmware .
73, AL? VE3RRD
On Sun, Jul 29, 2018 at 08:09 PM, Ken wrote:
Thanks all for the input.
?
Al Duncan, we're thinking of a transceiver for the next buildathon. Last Wednesday's meeting we asked for ideas. Transceiver sounds like what people want. I suggested the Nextion display for something a little fancier.
?
73
?
Ken VA3ABN
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I added an SMA connector instead of the existing connector. Should help with stray RF.
--
Mike
AI4NS
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Re: Gamma-matching antenna tuner
Ah, correction:
I saw somewhere that spurious emission OF UBITX is at the level of -45dB toward the fundamental frequency.// hiro
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Christopher,
I saw somewhere that spurious emission is at the level of -45dB toward the fundamental frequency.
However, Japan¡¯s latest spurious regulation requires more than -50dB and so I started thinking about pi-match tuner or BPF.
This doesn¡¯t mean that uBitx doesn¡¯t suppress good enough spur but it just means that Japan¡¯s regulation is a little tight, I suppose.
// hiro, JJ1FXF
Would they not just need band pass filters for whatever the desired band is? I kind of see where you might be able to suppress spurious emissions in a tuner, but why? My limited understanding is that the ubitx has filters for hf bands 20 meters and lower. Do they not provide enough suppression?? If not a filter should be pretty straight forward to construct. No?
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I am having issues with the keyer.? I will only use paddles for CW. Tip is dit, I connected the 2.2k to it. The middle contact is dah, connected the 10k to it. Other ends of the resistors are soldered together with the blue wire. The 4.7k is connected to the dit, and them to the green. What did I do wrong? I only get dahs,?
--
Mike
AI4NS
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Re: Gamma-matching antenna tuner
Christopher,
I saw somewhere that spurious emission is at the level of -45dB toward the fundamental frequency.
However, Japan¡¯s latest spurious regulation requires more than -50dB and so I started thinking about pi-match tuner or BPF.
This doesn¡¯t mean that uBitx doesn¡¯t suppress good enough spur but it just means that Japan¡¯s regulation is a little tight, I suppose.
// hiro, JJ1FXF
toggle quoted message
Show quoted text
Would they not just need band pass filters for whatever the desired band is? I kind of see where you might be able to suppress spurious emissions in a tuner, but why? My limited understanding is that the ubitx has filters for hf bands 20 meters and lower. Do they not provide enough suppression?? If not a filter should be pretty straight forward to construct. No?
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Re: End Fed antennas w/ uBITX
#ubitx
John,
Two ways.... peel away the goop and see.? the 1:1 is obvious.
The 1:9 if its really 1:9 put a 450ohm resistor (a 470 will do in a pinch) from the output terminal
to the coax ground with short leads.? The use an antenna analyser if its 1:9 then he reflected
SWR will be 1:1 or ver very close.
The inductance can only tell you the number of turns of the trifilar bundle.? To get that you need
the ferrite type and size and use one of the kits and parts calculators for that ferrite and do it by trial.
IF expect between 6 and 9 turns of the triple wires.
Did you look at the ERACHI End fed kit manual posted earlier today? it makes that 1:9 transformer.
Allison
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Re: End Fed antennas w/ uBITX
#ubitx
Hi Allison, I have been looking at how 9:1 are wound and most of them look like the example you shared, except for one and it kinda matches what I have. I have a twisted trifilar 4 wraps transformer but it's smaller than the example I found at -??I am including a picture, the one on the left is the new 9:1, and the right is the 1:1. And the inductance I didn't measure before is 197uH between posts on the 9:1. Is there an old school way to determine rf impedance with these measurements or does that require specific test equipment? Or am I fussing too much about something that's probably fine anyway? It's new territory. 
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Re: End Fed antennas w/ uBITX
#ubitx
Chuck,
Right on point.? You nicely summarized methods and process of antenna development
in an?antenna engineering firm I worked for.
Use case, establish what you need the antenna to do.? ?Also try to not succumb
to excess added features.? ?The other side of that is no antenna need be forever,
so try different things to meet the need. That includes ways to easily to raise and
lower antennas.
Design/build/evaluate/modify process is a well known engineering procedure
to developing a functional product.? To that I add conceive and evaluate candidates
as that is where the process is process started.? Its research, look at antennas and?
try to understand what they can do in a specific case.? ?Not all candidates pass
muster but one may be the diamond.? ?Also failures can evolve to be the niche
solution rather than the general.
Simplicity,?within the bounds of fitness for the design purpose.??
Always keep in mind the goal.? ?And if all else fails, KISS, then build it well.
All to often antennas are a target of magic thinking or outrageous claims.?
Substance is measurable, construction quality, material quality, applicability
and frugality.? The latter is not "is it cheap" but "is it a good value".
Allison
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I got some time to build up the power managememt, Si5351 and LCD sections.? Updates are posted to: www.w3jdr.com
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Re: End Fed antennas w/ uBITX
#ubitx
Indeed it does for many people.
The test method is not as exhaustive as I'd expect but...? 2450/800=3.mumble
as a SWR is low enough to be a measurement that can be used at the qualitative
level and with a compensating calculation would net quantitative evaluation.? I
suspect they wanted to run power through it as a lowly 2500 ohm 2 watt would
have done for simple testing.
Allison
?
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Re: Spurious RF at beginning of CW transmission in the uBitx
Bob,? Good work.? There was an earlier fix that tackled the fact that there is no pulldown? for the open contact its used two cross coupled 3904s to short the unpowered line RX+ or TX+. The side effect there are enough big caps that do not discharge fast. I believe the ubitx? fixes site has it, yes it does. Full description there... 
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Re: hacking bitx40 for 20 metre
#bitx40
On top of changing the BPF and the LO, you may have to change the BFO frequency (depending on which new VFO range you pick) and move it to the other edge of the IF pass band filter since 20m ham SSB uses USB.
Thang AA6SV
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Re: End Fed antennas w/ uBITX
#ubitx
Kickoff!
Read the review. Understand it is not an ARRL sanctioned review and was not done by their lab. Understand the efficiency measurement methodology was completely wrong. Other than that the review is fine. The antenna will make contacts.
WA8TOD
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Re: Spurious RF at beginning of CW transmission in the uBitx
On Mon, Jul 30, 2018 at 01:39 PM, <n1kw@...> wrote: Bob N1KW Every since the first BITX we have griped and complained about the 20 ms infamous "BITX Click" that occurs in changing over from receive to transmit and from transmit to receive.? Earlier tests indicated that it was somehow associated with hold-over voltage on capacitors between audio circuits and the balanced modulator.? Is it possible that you have now found, and fixed, that long-standing problem?
It appears that I have solved the problem! While analyzing the circuit further, I realized that the
large capacitor C52, which is charged during receive, would feed back through R52 and R18
keeping the receive path (Q10, 11, and 12) after the balanced modulator "hot" for a brief period.
When the transmit path is activated, the receive side of the circuit is going to remain on for some
period of time due to the time constants of C52 and its loads. It is understandable that if both
directions of the circuit are on, it could oscillate during that time!
To resolve the issue I simply added a diode in series with R52 (cathode toward C52) so that C52
can no longer back feed power to Q10, 11, and 12 upon initiation of transmit state. Now the transmitter
output looks perfectly clean on the spectrum analyzer at beginning if TX. Shorting the diode causes
the problem to show as before.
If this fixes that long-standing problem, then we all owe you a big THANK YOU.?
Arv K7HKL
_._
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Re: BITX40 relay K1 AND q13
HI Denis,
I do seem to remember this has come up before in the past, not sure what the outcome was, try a search, maybe something... I do like the idea of separating TX and RX even more...
73 Nick VK4PLN
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Re: Gamma-matching antenna tuner
You are right, Allison-san.
There should be a possibility of lower spurs on uBitx.
Thank you for letting me know it.
// hiro, JJ1FXF 2018/07/31 7:50¡¢ajparent1/KB1GMX < kb1gmx@...&²µ³Ù;¤Î¥á©`¥ë:
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Hiro san,
The NCO (form of synthesis) is very clean save for harmonics due to square waveform.
However there are three oscillators and mixers and the resulting combines can and do
create spurs.
Allison
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Re: Gamma-matching antenna tuner
¡°Not for a long time in prison¡± is a Good news, Iz. :)
Yes, I like 15m, too.
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I don't think you will be imprisoned for a long time because of the spurs and the harmonics of the Ubitx unless, as Allison pointed out elsewhere, you use the ssb mode above 20Mhz.
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Re: Spurious RF at beginning of CW transmission in the uBitx
Thanks Gordon! I have a simple solution in mind for the keying shape issue. I'll try it and, if it works, I will post it under a new thread.
73, Bob N1KW
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Re: Gamma-matching antenna tuner
Hiro san,
The NCO (form of synthesis) is very clean save for harmonics due to square waveform.
However there are three oscillators and mixers and the resulting combines can and do
create spurs.
Allison
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Nick VK4PP
