Re: QRP SWR meter recommendation?

Jerry Gaffke

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.

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

Nextion 3.5 with CEC 1.097

Michel Dupuy

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

Re: QRP SWR meter recommendation?

Tom, wb6b

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]) {
_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:
https://github.com/mountaintom/SmartLCDandIOexpander_I2C/blob/master/examples/SmartLCDandIOexpander_I2C_Backpack/SmartLCDandIOexpander_I2C_Backpack.ino

Tom, wb6b

Re: ubitx troubleshooting help - low power after irf510 replacement

Vince Vielhaber

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.

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...

Re: New Group Specifically for "Homebrew Test Equipment"

Vince Vielhaber

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.

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 <http://groups.io/g/hamtest>
* groups.io/g/homebrewhamtest <http://groups.io/g/homebrewhamtest>
(probably too long)
* groups.io/g/HBTE <http://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 <http://groups.io/g/BITX-SW>
* groups.io/g/BIT-SOFT <http://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 <http://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
<https://groups.io/creategroup>" page and
filling out the form. The groups.io <http://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
_._

Re: QRP SWR meter recommendation?

Gordon Gibby <ggibby@...>

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:

I use this one.

http://www.4sqrp.com/4stuner.php

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)

Re: QRP SWR meter recommendation?

Gordon Gibby <ggibby@...>

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.

On Aug 20, 2018, at 13:14, Bill Cromwell <wrcromwell@...> wrote:

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

Re: Nextion 3.5 with CEC 1.097

SV9CVJ Nikos

For GUI v3 please try this .
https://www.mediafire.com/folder/mmu6ua683lk93/Nextion-Screen-1097#g9pqdwt6i6u5s

I have ubitx_35_basic_90.tft and the card reader is down ,if card reader up load ..... 270.tft file .

Re: Nextion 3.5 with CEC 1.097

Michel Dupuy

Thank you Nikos. I tried 270tft the screen is reversed. 90tft is fine except the S / Meter deviation is reversed.
friendships
F1GTX Michel

Re: Intermodulation Performance

Warren Allgyer <allgyer@...>

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

Re: uBITX new build, quiet audio

jfein2000@...

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

Re: Nextion 3.5 with CEC 1.097

SV9CVJ Nikos

Ηi 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 :  https://www.facebook.com/groups/uBITX/?fref=nf&__xts__[0]=68.ARCZBFSjpXWzAphJfshegxYbIK0Qi0etEyNuQTcD_pwl-rupMgt9xw6X5GtdY4LDcscW2lFL3YnNJszW9B4P4Ik5ynLYdUji6skdKUo_BmShDeNLR1TF7Hvu8qlqLeXayyJ867Srpasm&__tn__=C-R

SV9CVJ  Nikos Magafourakis

Re: Intermodulation Performance

Gordon Gibby <ggibby@...>

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

On Aug 21, 2018, at 06:35, Warren Allgyer <@allgyerw> wrote:

response

Re: uBITX new build, quiet audio

Henning Weddig

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 (=1µV) 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:

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

Re: NEW DISCUSSION GROUP SPECIFICALLY FOR HOMEBREW TEST EQUIPMENT

Good idea,  getting harder to get good second had test equipment

On 21 Aug 2018, at 10:31 am, Arv Evans <arvid.evans@...> wrote:

The new discussion group has been formed.

HBTE+subscribe@groups.io

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
_._

Re: NEW DISCUSSION GROUP SPECIFICALLY FOR HOMEBREW TEST EQUIPMENT

Sudipta Ghose VU2UT

Great!

On Tue, Aug 21, 2018 at 5:40 PM, Adrian Waiblinger wrote:
Good idea,  getting harder to get good second had test equipment

On 21 Aug 2018, at 10:31 am, Arv Evans <arvid.evans@...> wrote:

The new discussion group has been formed.

HBTE+subscribe@groups.io

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
_._

--
One of those ... ...

Re: uBitx diagnostic document from Facebook group

Roy Appleton

I must have missed something, where's this guide?

Roy
WA0YMH

On Thu, May 17, 2018, 11:15 PM Tom, wb6b <wb6b@...> wrote:
Thanks to Ufi Auttorri for creating this guide. It was certainly a lot of work to do this.

Re: Nextion 3.5 with CEC 1.097

Michel Dupuy

Thank you Nikkos.
Michel F1GTX

Re: QRP SWR meter recommendation?

Jack, W8TEE

Tom:

You can get a marginal speed improvement by moving the data definitions out of the loops. For example:

``#define ELEMENTS(x)  (sizeof(x) / sizeof(x[0]))  // Gets rid of "magic numbers" in the code``
`float scaledReadin;`
`for (int pin = 0; pin < ELEMENTS(_analogValue); pin++) {`
`   if (_analogActive[pin]) {`
`    `` scaledReading = analogScalingFactor * (float)analogRead(pin);`
`     _analogValue[pin] +=```` (scaledReading - _analogValue[pin]) * _analogFilterValue[pin]; ```
``````   }
}``````
The macro ELEMENTS() allows you to determine the number of elements in an array automatically a compile time, thus eliminating the need to hard-code array sizes into the body of the program. That way, you can simply change the definition of the array in one place in the code, recompile, and the new size is automatically changed everywhere in the code. The really nice thing about the macro is that it's completely typeless...that it, it will work with any aggregate data type.

Moving the definition of a variable before and outside the loop saves the compiler the instructions necessary to adjust the stack pointer on each pass through the loop in the "in-scope, out-of-scope" aspect of a data definition within the loop. Quite honestly, on 8 iterations of the loop it will not likely be noticeable. Still, in other programs where SRAM is pretty tight, it could mean the difference between running and a stack crash.

Jack, W8TEE

On Tuesday, August 21, 2018, 1:02:39 AM EDT, Tom, wb6b <wb6b@...> wrote:

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]) {
_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:
https://github.com/mountaintom/SmartLCDandIOexpander_I2C/blob/master/examples/SmartLCDandIOexpander_I2C_Backpack/SmartLCDandIOexpander_I2C_Backpack.ino

Tom, wb6b

Re: QRP SWR meter recommendation?

Lee

If you want SWR only I just got a nice cross needle MFJ-822.   It covers 1.8-200 MHz, 30 or 300 Watts.  On the 30 watt range half scale is about 7 watts.
--
Lee - N9LO  "I Void Warranties"