Re: Erroneous embedded wattmeter reading
Thanks Evan.
I just update to the latest version. Nothing? changing...
I will try with a ham wattmeter (that I must buy and cost the same of the sbitx)...
Bye
Carlo IS0HLX
Il 24 Maggio 2024 12:25:28 CEST, Evan Hand <elhandjr@...> ha scritto:
Carlo,
The last thing to try would be to update the software.? I do not have any other suggestions, as this is a new first-time power-up.
Maybe Ashhar Farhan or one of the other experts in the group has other ideas.
73
Evan
AC9TU
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I wasn’t able to attend FDIM, but I would be interested in getting an sbitx hat if any attendee has one they have changed their mind about using. I would be happy to pay shipping of course, and make a nominal donation to HFSignals and QRP ARCI to help support the biofuels required to advance the project.
72,
Mark KI4HQK
On Thu, May 23, 2024 at 7:24?AM Ravi Miranda via <ravimiranda= [email protected]> wrote: Just checking, as I couldn't make it to FDIM, did the new? driver and
predriver details get discussed or released?
Ravi/M0RVI
On Thu, 23 May 2024 at 04:19, Neil R. Ormos N9NL via
<ormos-lists=[email protected]> wrote:
>
> Bob Bennett wrote:
>
> > I missed part of Farhan's presentation (guys
> > behind me talking too much) but I did get one of
> > the chips that he passed out. I want to set up a
> > project with it but need some more info, pinout,
> > etc. can someone post it.
>
> If you are referring to A F's talk at FDIM, there was an addendum to the FDIM Proceedings entitled "The sBitx Hat" that included that information.? It was distributed with the Proceedings as a separate sheet (unbound), as was the FDIM schedule.
>
> I think the same information is available on the Github site:
>
>? ?<>
>
> The schematic is one of the files listed near the top of the page.
>
> 73
>
> --Neil Ormos N9NL
>
>
>
>
>
--
I'm here to add more value to the world than I'm using up.
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Re: Erroneous embedded wattmeter reading
Carlo,
The last thing to try would be to update the software.? I do not have any other suggestions, as this is a new first-time power-up.
Maybe Ashhar Farhan or one of the other experts in the group has other ideas.
73
Evan
AC9TU
|
Re: Erroneous embedded wattmeter reading
I make this calculation:
I measured about 80 V peak to peak on the scope. The positive half wave is 80Vpp/2=40V -》the integral of the positive half wave is 40V/sqrt(2)=28.3 Vrms --》the power is (28Vrms)^2/50ohm=16W. The same with your formula. The reading on the embedded meter is around 23W. I used a Tee with a 20:1 attenuator on the dummy load on the 7Mhz band and I had 1.2 SWR on the embedded meter. What's wrong? Maybe the oscilloscope... but if I measure on the calibration output it correctly read 1V... Thanks for your reply.
Il 24 Maggio 2024 11:27:59 CEST, Evan Hand <elhandjr@...> ha scritto:
Hello Carlo,
Since it is off by a factor of 2, my first thought is that your scope measurement may be peak to peak instead of peak, and you are using the wrong formula to calculate the power.
power = (Vpp)^2/400 = (Vpeak)^2/200
(^2 indicates squared)
73
Evan
AC9TU
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Re: Erroneous embedded wattmeter reading
Hello Carlo,
Since it is off by a factor of 2, my first thought is that your scope measurement may be peak to peak instead of peak, and you are using the wrong formula to calculate the power.
power = (Vpp)^2/400 = (Vpeak)^2/200
(^2 indicates squared)
73
Evan
AC9TU
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Erroneous embedded wattmeter reading
I'm setting up a new sbitx v3.
The reading of the embedded power meter is about twice the reading done with the oscilloscope on a 50 ohm dummy load. The "bridge" parameter in user setting ini file is equal 100. If I reduce the parameter I increase the embedder meter reading but I want to reduce it. The maximum value that the bridge parameter use is 100, if I increase over 100 the reading in the embedded meter doesn't change... Anyone have a problem like mine?
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Awesome, thank you -- '72
Aaron?
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Bob,
I have tried many different attenuators.? Everything from homebrew 50db taps to 100watt 40db inline models.? I currently use either the 100watt 40db attenuator:
or a 25 watt 50 DB attenutor:
This is followed by a step attenuator like this (the one that I have is no longer sold):
You will need the adapters and cables as well.
The step attenuators are key to verifying whether the signals are internal or external to the measuring device.? They also allow adjustment for the best resolution of the measurements.
73
Evan
AC9TU
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I have those.? May I ask what attenuator you use with them?? I built the one at dl1ycf.darc.de/dummy1.jpg but haven't tested it yet.? I didn't include the antenna out switch and Jack.
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Bob,
The Antuino is a compromise combination of a scalar antenna analyzer and a scalar frequency analyzer.? There are better versions of each for less than the Antuino price.? You would need two to get the same types of analysis, though with much better accuracy and definition.? The two devices are:
- NanoVNA or NanoVNA-H4 (Other variants may be better.? I last looked at these in Feb. 2021)
- TinySA or TinySA Ultra
I recommend going to the TinySA.org wiki to find a seller of an original device in your region.? Due to the frequency span and resolution bandwidth, I prefer the more expensive Ultra, which is twice the cost of the base TinySA.??
I bought my NanoVNAs (I have bought two and gave away one) from Amazon and R&L Electronics:??
.
Amazon also sells the nanoVNA:
73
Evan
AC9TU
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Monteverde sells boxes of pen/stylus combinations that are oddly close to the original design of the Lunatik pens created as a Kickstarter project shortly after Kickstarter came into being. They're the soft carbon sponge tip, but the ballpoint pen sticks out through a hole in the stylus when you push the clicker on the back. I used one of those with my sBitX until I gave up and just plugged in a Logitech dongle and used it with a spare 2.5ghz trackball I had lying around. THAT works like a CHAMP, btw. The touchscreen is so coarse, I can't click on the correct line in the FT8 receive list to save my life. I always get the one above or below the one I'm trying to click, which makes me click ESC a LOT. The mouse is a ton more accurate. Note that I do not say totally accurate, because sometimes where to click on something so as to select it is a little, how shall I say it, vague. Yes, vague is almost right. Unclear would work, as would uncertain...but I'll settle on vague because it has the fewest syllables.?
See? or? for a color assortment. They DO work, just not as well as a mouse.
-=-=-=-=-=-=-=-=- 73, Gwen, NG3P
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Aaron: Farhan’s 2924 FDIM presentation is on YouTube at:
73 KB5QR, Don
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Nice lumber! When I am outside with the radio supervising the grandkids, I use a very small wireless mouse/keyboard combo. It works pretty well. I still use the tuning knob though.
Scotty WD4PYT?
Just a thought here. A big hang up with me is the knobs and their placement. I spent a fair bit of time making a nice wooden case for the sBITX. I made it out of red oak and purple heart.?
Here are a couple pics of the front of it.?
 
Nothing fancy just some oak with a purple racing stripe to double the transmit power. The knobs really don't look that bad on it. The can look pretty sweet on it.?
Just a thought to see what you think of this thought. Lot of thoughts here.?
I have made around 1,500 QSL's with the sBITX until I fried it (another thread) I just realized that I hooked up the knobs when I first got the sBITX. Since I don't have an enclosure for it the knobs just kind of dangled on the end of it cable. So I quickly unhooked the knobs and put them away for safe keeping. instead of using the knobs I just use a wireless keyboard and mouse that uses a USB dongle.
So do I really need the knobs??
Not using the knobs would give it a much cleaner front panel. Then there would be nothing attached to the wood parts of the enclosure. I'm using a piece of sheet metal from a filing cabinet as the back panel and the BNC connector, power plug and switch and the 3.5mm jacks will be located on the back panel. So from the front all you would see is the 7" touch display and 2 small speak grills and possibly the built in microphone.??
--
'72
Aaron?
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Re: Is this the radio for me? Your opinion, please.
You can use the sBitX out of the box as is.?? Mine worked first time and has consistently worked every day since. ? I have faith it would remain that way for quite some time if you left the operating system alone and just fired it up to use it. ?? I believe however that the vision for the sBitx was to provide a system to help you expand your knowledge of SDR design while also enjoying a very functional device.?? If you are not interested in learning SDR theory and design or the pi/debian linux OS there are better choices out there.?? If you are interested, sBitX opens the door to SDR university with a world of professors willing to help you.
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Just a thought here. A big hang up with me is the knobs and their placement. I spent a fair bit of time making a nice wooden case for the sBITX. I made it out of red oak and purple heart.? Here are a couple pics of the front of it.?   Nothing fancy just some oak with a purple racing stripe to double the transmit power. The knobs really don't look that bad on it. The can look pretty sweet on it.? Just a thought to see what you think of this thought. Lot of thoughts here.? I have made around 1,500 QSL's with the sBITX until I fried it (another thread) I just realized that I hooked up the knobs when I first got the sBITX. Since I don't have an enclosure for it the knobs just kind of dangled on the end of it cable. So I quickly unhooked the knobs and put them away for safe keeping. instead of using the knobs I just use a wireless keyboard and mouse that uses a USB dongle. So do I really need the knobs?? Not using the knobs would give it a much cleaner front panel. Then there would be nothing attached to the wood parts of the enclosure. I'm using a piece of sheet metal from a filing cabinet as the back panel and the BNC connector, power plug and switch and the 3.5mm jacks will be located on the back panel. So from the front all you would see is the 7" touch display and 2 small speak grills and possibly the built in microphone.?? -- '72
Aaron?
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Any suggestions?
73,
Bob Brown?
KD2YUG?
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I use a bamboo chop stick, works great and is long enough for me to hold comfortably?? -- '72
Aaron?
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Hope they put it online, it would be pretty informative.? -- '72
Aaron?
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I agree with Ashhar. I have never encountered any overheating yet.
Scotty WD4PYT?
None. The heatsink is enough. I have used it in 110F in the field without a problem. - f
Having the box from Sbitx, what is recommended for a fan to pull or push the air inside?
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Re: Is this the radio for me? Your opinion, please.
I have the sBitx V2 running V3 software and it runs great. ?I have never had to go in the operating system and monkey around. ?If you like how it works out of the box you are good. ?It does SSB well, and the native FT8 is excellent. ?I hear it is also excellent on CW. ?But the radio allows you to go in and add additional software and experiment, so you have that option as well
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Aaron K5ATG
Bob Brown
Gwen Patton
Scotty R