Re: NEW DISCUSSION GROUP SPECIFICALLY FOR HOMEBREW TEST EQUIPMENT
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On Tue, Aug 21, 2018 at 5:40 PM, Adrian Waiblinger <vk5zbr@...> wrote: Good idea, ?getting harder to get good second had test equipment
The new discussion group has been formed.?
?
Three persons have volunteered to be moderators (Gilles, Dennis, and Jim).? I will make them moderators
just as soon as they have subscribed to the new group.?
Concept for this group is that it will focus on Amateur Radio Test Equipment that you have designed and built.
Operation and testing with homebrew test equipment is also a suitable topic.?
The intent is to stimulate design and construction of near-lab-grade but inexpensive test equipment for use by
radio amateurs.? I am guessing that a lot of this will involve micro-controllers, but we shall see where the
discussions take us.?
Arv? K7HKL
_._
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Re: NEW DISCUSSION GROUP SPECIFICALLY FOR HOMEBREW TEST EQUIPMENT
Good idea, ?getting harder to get good second had test equipment
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On 21 Aug 2018, at 10:31 am, Arv Evans < arvid.evans@...> wrote: The new discussion group has been formed.?
?
Three persons have volunteered to be moderators (Gilles, Dennis, and Jim).? I will make them moderators
just as soon as they have subscribed to the new group.?
Concept for this group is that it will focus on Amateur Radio Test Equipment that you have designed and built.
Operation and testing with homebrew test equipment is also a suitable topic.?
The intent is to stimulate design and construction of near-lab-grade but inexpensive test equipment for use by
radio amateurs.? I am guessing that a lot of this will involve micro-controllers, but we shall see where the
discussions take us.?
Arv? K7HKL
_._
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Re: uBITX new build, quiet audio
#ubitx
Jeff,
I have the same impression and experience like You!
I prodduced a so called level diagramme, see may attachment.
Interestingly thsi result was verified on my UBITX: at -107 dBm
(=1?V) at the antenna input I measured about 300 mVpp? = 106 mVrms
at the louespeaker terminals; audio control potentiometer at full
gain. This level (into a 8 ohm impedance ludspeaker) gives about
1,4 mW of power.
Doing the samce lvel diagramme for the BITX40 gives 15 dB higher
gain: thre RF stages?? (but lower gain each stage), (two on the
UBITX) and a 6 dB higher audio gain (LM386). 10^(15/10) gives a
poer factor of 31.67, so the BITX40 would output 44.27 mW under
the same input conditions. ? ?
I also noticed a large amount of RF still at the loudspeaker
terminals, about 100 mVpp. Using a frequency counter I observed 12
MHz, so this RF are leaks of the BFO.
One remedy coud be to palce a 100 pF cap across R50 (AF preamp).
Henning Weddig
DK5LV
?
Am 21.08.2018 um 12:38 schrieb
jfein2000 via Groups.Io:
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I have a current version of the BITX which I just finished
assembling in the case.? It works after some
debugging....replacing the code in the Arduino due to a cw fault
per another discussion.? It is now working on ssb and cw
although power output should be higher on 80 and 40 meters. BUT,
I also feel the audio is too low.? I don't have a hum issue but
at full volume I can hear stations but even with an amplified
speaker it is just not up to snuff.? I saw Arv's suggestion for
wiring an amplified speaker to the volume control and will try
that to see if it helps. I am responding to this post as the cw
issue seems to be? general fault and with two of us with recent
bitx builds having audio issues I felt it would be good to get
this on the radar in case it is a trend building. ? Any other
suggestions to remedy would be appreciated. ?
cheers
Jeff?
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Re: Intermodulation Performance
Hi,Warren, I will always appreciate the data that you generated!
Nicer radios, are certainly nicer radios! Some people like Honda FIT , some prefer a high end BMW!
For the purposes of coaxing local club members into learning HF and some radio, some building techniques, & electronics, this is perfect!
For HF ALE monitoring, it even beats the heck out of my ICOM 718¡¯s. For winning a contest? Nah!!
Thanks for all your input
Gordon
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On Aug 21, 2018, at 06:35, Warren Allgyer <allgyer@...> wrote:
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Re: Nextion 3.5 with CEC 1.097
¦§i Michel,
I already know that the software has some issues, but it's the best option i've found thanks to Rich Neese.You can also find GUI here :?
SV9CVJ? Nikos Magafourakis
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Re: uBITX new build, quiet audio
#ubitx
I have a current version of the BITX which I just finished assembling in the case.? It works after some debugging....replacing the code in the Arduino due to a cw fault per another discussion.? It is now working on ssb and cw although power output should be higher on 80 and 40 meters. BUT, I also feel the audio is too low.? I don't have a hum issue but at full volume I can hear stations but even with an amplified speaker it is just not up to snuff.? I saw Arv's suggestion for wiring an amplified speaker to the volume control and will try that to see if it helps. I am responding to this post as the cw issue seems to be? general fault and with two of us with recent bitx builds having audio issues I felt it would be good to get this on the radar in case it is a trend building. ? Any other suggestions to remedy would be appreciated. ?
cheers
Jeff?
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Re: Intermodulation Performance
I am finished. This is simply not worth the effort. The difference between this radio and my FT-817 is about $350. The difference between the uBitx and my HobbyPC RS-HFIQ is $100. Both are worth the increment in order to assure:
1) FCC/ITU compliant transmissions
2) Excellent IMD and in-band spurious response
3) Adequate audio output
4) AGC
5) ALC
Not to mention FM, 6m, 2m, 70 cm for the Yaesu.
I completely understand the attraction of making up your own box, modifying the code, and other customizations. But there is simply too much to be added to the basic uBitx as delivered in order to make it a compliant, user-friendly, neighbor-friendly rig. I maintain it is not possible to make compliant transmissions from this board without the knowledge and equipment to modify it for compliance and a properly equipped lab to set it up and monitor it.
My board is going on the shelf marked "Nice try....... not worth the effort", along with a complete set of filter relays, failed output filter attempts, octal to decimal decoders to drive the filters, 45 MHz SAW filters, and a stack of test data. It was fun. It is done.
WA8TOD
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Re: Nextion 3.5 with CEC 1.097
Thank you Nikos. I tried 270tft the screen is reversed. 90tft is fine except the S / Meter deviation is reversed.
friendships
F1GTX Michel
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Re: Nextion 3.5 with CEC 1.097
I have ubitx_35_basic_90.tft and the card reader is down ,if card reader up load ..... 270.tft file . 
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Re: QRP SWR meter recommendation?
#ubitx
Here is an example of one of the little swr indicators ?where you just dim the diode
I¡¯ve used that kind of a circuit as well as the two torrid system ?others recommended which also works fine but you¡¯ll need an external meter or voltmeter or something.?
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Hi Mike,
The tuner itself does not care how much power you use to 'set' it as long as it isn't *more* than it can handle. It is not impressed if your TX can pin the needle or not. If your uBitx will only drive the meter to half scale in it's "Forward" configuration
then set the "Cal" knob full right. Flip the switch to "Reverse" and adjust the tuner for minimum as per usual. If you can get it all the way to zero - well zero is still zero. And less is still less. So what if you can't read that it is 1.25 to 1 if it is
1.25 to 1. A zero in "Reverse" is 1:1 no matter how high the TX didn't drive the needle in "Forward".
I built an SWR bridge that could be pinned with less than two watts (maxed at about 30) and discovered that it doesn't make any difference as described above. What does make a difference is a tuner and SWR bridge built for QRP power levels can be made
much smaller and lighter:) Put the tuner and the bridge in the same box together for even more convenience out in the field. Like a scaled down version of your MFJ. If you build it into your uBitx you will forfeit using it with other radios but will be even
more convenient when taking the uBitx to the field.
Keep us posted with progress.
73,
Bill ?KU8H
On 08/20/2018 11:31 AM, Mike KK7ER wrote:
So far I have been setting the antenna tuner using my Kenwood and then
swapping in the uBITX. ?But now we want to take the uBITX on the road.
Problem is that the uBITX does not put out enough power for full
deflection on our MFJ versa tuner II so we cannot get an accurate SWR
reading to tune the antenna. ?Does anyone have recommendations for a QRP
SWR meter? ?Thanks!
73, Mike KK7ER
(and son KI7ZZS)
--
bark less - wag more
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Re: QRP SWR meter recommendation?
#ubitx
If you look at the schematic of your tuner, there is probably one or two resistors in a voltage divider chain that you could parallel ?something with to increase the voltage that gets to the meter. ?Either before or after the rectifier diode or diodes. ?Just
make sure that whatever gets done to the forward circuit is the same as what gets done to the reverse circuit
Secondly, you don¡¯t have to have a full-scale indication to figure out your swr. ?It¡¯s a relative measurement. ? If the reverse is 50% of the forward on the meter range, most of the time youre at 3 to 1. ?You could look at how yours is calibrated to verify
that. ??
You can first do a rough tune just using the receiver, adjusting for loudest receive noise. Then get the transmitter going & null out the return as low as you can.
Some of the other people may already have pointed it out, but there are several excellent little qrp swr kits out there that implement a simple resistive bridge circuit going to an LED diode, and you adjust tuner for the dimmest diode or so. ? They are
basically comparing against a 50 Ohm load and when your Antenna has been transformed into 50 ohms there is no longer relative voltage between the Antenna and the reference 50 ohms, so the light emitting diode goes dark.
Cheers
Gordon
On Aug 20, 2018, at 12:39, V Zecchinelli < n1vin@...> wrote:
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I use this one.
ince, N1VIN
On 8/20/2018 11:31 AM, Mike KK7ER wrote:
So far I have been setting the antenna tuner using my Kenwood and then swapping in the uBITX.? But now we want to take the uBITX on the road.? Problem is that the uBITX does not put out
enough power for full deflection on our MFJ versa tuner II so we cannot get an accurate SWR reading to tune the antenna.? Does anyone have recommendations for a QRP SWR meter?? Thanks!
73, Mike KK7ER
(and son KI7ZZS)
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Re: New Group Specifically for "Homebrew Test Equipment"
When I'm googling for something home brewed, I use the term DIY. Such as DIY screwdriver antenna. I get the most hits that way.
Vince.
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On 08/19/2018 06:09 PM, Arv Evans wrote: Hello
A few days ago I mentioned an idea for starting a separate discussion
group for
home-brew ham radio test equipment. The idea still seems interesting
but I seem
to be struggling with what to call the group. It needs to be short
enough to type in
easily, and still definitive enough to not be confused with equipment
for testing
pigs or homemade beer, Some possible options that come to mind:
* groups.io/g/hamtest <>
* groups.io/g/homebrewhamtest <>
(probably too long)
* groups.io/g/HBTE <> (*H*ome *B*rew *T*est
*E*quipment)
* or....?
There are probably a myriad of better names. Any ideas?
My Linux NFS File Server has a Test Equipment directory that already has
several ideas which could be used as a start for this new discussion group.
I am sure that others have similar card files or computer files which
would be
interesting to the rest of us who like building our own test equipment.
This
does raise questions about how to differentiate hardware test equipment
projects from combination hardware and software based test equipment?
On a slightly different direction........
In the past there have been a few complaints about the amount of software
discussion here on the BITX20 forum. That raises the question of possibly
starting a separate discussion group specifically for software that is
relative
to BITX based equipment. Again, if such a forum were established, what
should it be called?
* groups.io/g/BITX-SW <>
* groups.io/g/BIT-SOFT <>
* groups/g/BSoft
* or...?
In the case of Homebrew Test Equipment and a possible new BITX-Software
group we would need a couple of volunteer moderators for each group.
We already have spawned an Antenna discussion group at
groups.io/g/antennas <>
which is working quite well. The moderators are doing a good job and some
interesting discussion has started.
I can start new discussion groups, but it is possible that someone else
could do
the same. The process involves logging into the "create a group
</creategroup>" page and
filling out the form. The groups.io <> process is quite
easy and straightforward.
It will not hurt my feelings if you want to start one of the above
groups, or another
group. If you have ever envisioned yourself as being the Lord and King
of a
discussion group...Go For It !
Arv K7HKL
_._
--
Michigan VHF Corp.
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Re: ubitx troubleshooting help - low power after irf510 replacement
Stay away from their 1/8" phone plugs. I had the tip of one fall off inside a jack. Problem was the jack was on the back of my Kenwood TS430 and I had to pull the back panel to get the jack out to get that piece out. After looking closer at the other ones I have, they're all loose - even the new ones in the drawer.
Vince - K8ZW.
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On 08/18/2018 10:17 AM, ohwenzelph via Groups.Io wrote:
It would be nice to know what is and is not good from Tayda as they have
low prices and low cost shipping.guress sometimes you git what you pay
for...
--
Michigan VHF Corp.
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Re: QRP SWR meter recommendation?
#ubitx
Here are some code snippets from a project I did. It calculates SWR from the voltages read from analog pins A6 and A7. It does a number of other things, so here are the basic pieces of code for SWR extracted out into small snippets. This first code segments captures selected analog pin voltages and applies an exponential smoothing filter to them.
for (int pin = 0; pin < 8; pin++) {
if (_analogActive[pin]) {
float scaledReading = analogScalingFactor * (float)analogRead(pin);
_analogValue[pin] +=
(scaledReading - _analogValue[pin]) * _analogFilterValue[pin];
}
}
This next slice of code captures the max voltage and applies a slow decay to the max value.
// Capture the peak analog values with a slow decay time.
// The decay time is a starting point. May want to adjust it to taste.
float decayValue = 0.001;
for (int pin = 0; pin < 8; pin++) {
if (_analogActive[pin]) {
float analogValue = _analogValue[pin];
_analogValueMax[pin] = max(_analogValueMax[pin], analogValue);
_analogValueMax[pin] += (analogValue - _analogValueMax[pin]) * decayValue;
} else {
_analogValueMax[pin] = 0.0;
}
}
And here the SWR is calculated from the Max values.
// "SWR"
float vf = _analogValueMax[6];
float vr = _analogValueMax[7];
float vd = (vf - vr);
vd = max(vd, 0.002); // Limit max SWR reading before divide by zero
// Calculate SWR from directional coupler voltages.
result = String((vf + vr) / vd);
You can see the full code here: Tom, wb6b
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Nextion 3.5 with CEC 1.097
Hello everyone and thank you for the work. I will want to know if someone has made the firmware for Nextion 3.5 with CEC 1.097. Thank you Michel
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Re: QRP SWR meter recommendation?
#ubitx
Correct, no meter provided.
A DVM is sufficient.
Or could go into analog pin A7 (with an analog switch to select forward/reverse) of the Nano.?
Perhaps both A6 and A7, use D0,D1 for the keyer if you want CW.
Let the Nano take care of the math.
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On Mon, Aug 20, 2018 at 09:06 PM, Mike KK7ER wrote:
Allison, the instructions are pretty terse.? Looks like the meter/meters does/do not come with it.? How does it work?? Use a DMM to measure forward and reverse voltages and do the math in my head?? Thanks!
73 Mike KK7ER
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Re: QRP SWR meter recommendation?
#ubitx
Allison, the instructions are pretty terse.? Looks like the meter/meters does/do not come with it.? How does it work?? Use a DMM to measure forward and reverse voltages and do the math in my head?? Thanks!
73 Mike KK7ER
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Re: QRP SWR meter recommendation?
#ubitx
Bill, I guess you are right.? I ought to be able to do some experiments before we leave to get a sense for how the MFJ performs at low power.? If I can understand what readings correspond to 2:1, I can keep it below 2:1.? And we can order one of the kits and take our time building it.? Thanks!
73 Mike KK7ER
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Re: uBitx diagnostic document from Facebook group
#ubitx
this will save a lot of people a lot of time.
--
72 and God bless
KD4EPG
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Re: uBitx diagnostic document from Facebook group
#ubitx
I agree, John. I just found this. I think it ought to be on the website, readily available to all. I wish I had had it weeks ago..
--
72 and God bless
KD4EPG
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SV9CVJ Nikos