Here's the datasheet:
? ??
Pages 20-23 are of interest.
Looks to me like it is on the order of 10 bytes transferred via the i2c bus for each ADC read,
since we have to switch channels between reads to choose forward vs reflected power.
At 100 khz, that's 10us * 10 * 8bits/byte = 800 us.
That's an order of magnitude slower than reading the Nano's ADC using a an analogRead() call, around 100us.
It is possible to speed the i2c bus up from 100 khz to 400 khz,
But we can speed up the Nano ADC reads by a factor of 5, fiddling with the ADC clock prescaler.
So using the Nano's ADC is much faster than using this i2c ADC chip
Now if you found a good SPI ADC chip, that might be a different story.
Jerry
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Re: ND6T AGC implementation for uBIT-X
I made this point earlier. If you are tuning for minimum reverse power you actually don't have to do any computation. Just output the reading from the adc, be it an adafruit ads1015 or an AD8307. If the reading is going down then so is the reverse power. Minimum load on the nano. tim ab0wr On Sun, 06 May 2018 17:26:55 -0700 "Kees T" <windy10605@...> wrote: So what would be the minimum compute requirement on an existing
Nano ? Maybe read 2 analog inputs directly from 2 AD8307s? with only
a scaling factor for Stockton Bridge coupler loss. Multiply that by
1dBm per 25mV (linear spec for the AD8307) and you have the Forward
and Reflected power in dBm into a 50 ohm load.? Look up the "power"
in Watts or tape a small chart on the bottom of the uBITX.
73 Kees K5BCQ
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Re: ND6T AGC implementation for uBIT-X
Jerry, Do you have a portable antenna that is flat from 3500khz to 4000khz? Go from one end of the band to the other and see if you are getting reverse power at any point. I don't put a unit in my go box that I question whether it is operating or not. If operation is questionable then it isn't a unit you want to depend upon in the field. tim ab0wr On Sun, 06 May 2018 17:24:55 -0700 "Jerry Gaffke via Groups.Io" <jgaffke@...> wrote: There are times when I'd like to know if the rig is working.?
On Sun, May 6, 2018 at 04:59 pm, Tim Gorman wrote:
Forward power, and using it to calculate SWR, tells you more about
how your rig is operating then about the match to the antenna.
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Re: ND6T AGC implementation for uBIT-X
How often in a portable operation do you connect to an antenna that has *no* reverse power? An antenna that is perfectly flat on all frequencies? If you are using a tuner it's pretty simple to see if the rig is putting out any power. Just tune away from what you think is a perfect match. I measure PA current to actually tell if the rig is working. Using an i2c current sensor. tim ab0wr On Sun, 6 May 2018 20:38:36 -0400 "Vince Vielhaber" <vev@...> wrote: If you're only looking at reflected power and it's flat you don't
know if you have a good swr or the radio isn't putting out. Now if
you're also looking at forward power, the mystery is solved.
Vince.
On 05/06/2018 07:59 PM, Tim Gorman wrote:
A simple measure of reverse power will tell you if the antenna is
working ok.
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Re: ND6T AGC implementation for uBIT-X
That's basically what I am using. Except an LED won't read clear down to zero reverse power. tim ab0wr On Sun, 6 May 2018 19:14:46 -0500 "K9HZ" <bill@...> wrote: I guess then to take it a step further, all you need is the reverse
line section, a diode, a couple of RF blocking capacitors, a
resistor, and an LED. LED blinks when there is reverse power. You
could make that for less than $1.
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ
Owner - Operator
Big Signal Ranch ¨C K9ZC
Staunton, Illinois
Owner ¨C Operator
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Soufriere, St. Lucia W.I.
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Why is the i2c so much slower? When using the adafruit ads1015 the entire analog to digital conversion is completely off-loaded from the nano. All you have to do is read the registers in the ads1015. There is a small amount of overhead in the i2c communication protocol but it isn't significant from what I can see. It isn't a matter of how fast the analog to digital conversion can be done because you don't have to read the voltage repetitively as fast as you can. You can't adjust a tuner faster than the nano can read it from an i2c adc. There was an earlier thread where it was argued that off-loading everything you could from the nano to an attached processor provided more cycles for things the nano *has* to accomplish. I would think that would surely include doing analog-to-digital conversion. tim ab0wr On Sun, 6 May 2018 15:24:42 -0500 "AA9GG" <paul.aa9gg@...> wrote: I agree the I2C would be a lot slower. You are better off using the
ADC inputs directly and let it "free-run" (I use ADC6 and ADC7).
That way when you need to access the data, it's just a quick check of
the "conversion complete flag" and grab the data from the registers.
On Sun, May 6, 2018 at 2:35 PM, K9HZ <bill@...> wrote:
We must use different libraries. I send out the start conversion
word to the part address¡ and away it goes. Then sometime later,
I poll to see if conversion is ready/ do a read at the same time
(because you get one or the other for free). If the data isn¡¯t
ready, throw away what you got back and go do something else. If
you test every quarter-second, you would always get the data and
the ready bit set TRUE. Then update the display. Again, the time
it takes to do the A/D conversion isn¡¯t important off-board as long
as both power readings are congruent and ready together at some
point. The reads can be executed whenever convenient as not to
interfere with keying, CAT commands, etc. without using interrupts.
With all this said, I support using a couple of caps and doing
something really easy. Maybe it works perfectly.
*Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ
PJ2/K9HZ*
Owner - Operator
Big Signal Ranch ¨C K9ZC
Staunton, Illinois
Owner ¨C Operator
Villa Grand Piton ¨C J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com <>
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Moderator ¨C North American QRO Group at Groups.IO.
email: bill@...
*From:* [email protected] [mailto:[email protected]] *On Behalf Of
*Jerry Gaffke via Groups.Io
*Sent:* Sunday, May 6, 2018 1:54 PM
*To:* [email protected]
*Subject:* Re: [BITX20] SWR
You said
> goes on about its business for a while
That's not correct, unless you add some code to handle i2c transmit
and receive in
interrupt routines. That's some code most of us would prefer to
avoid.
We currently do blocking IO on I2C reads and writes.
Just clocking all those I2C bits around at 100khz takes
considerably more time than doing the embedded ADC reads.
I'm assuming we are mostly concerned about delaying other
operations, such as sensing the keyer.
If all you are worried about is how synchronous the two samples are,
then yes the 2 channel ADC chip on the I2C bus would be better,
even if we stick with the blocking code on i2c access.
Me, I'll try out a couple big caps first.
Jerry
On Sun, May 6, 2018 at 10:50 am, K9HZ wrote:
¡°Actually, reading values from an A/D over the I2C bus will take
more time than just reading from the Nano's embedded ADC. ¡°
Yes, but in this case, taking more time is ok¡ because the Arduino
commands the A/D to perform its function, goes on about its
business for a while¡the digitization happens independently of the
Arduino processing, and the data will be waiting for you want to go
get it. There is no real demand on when the data needs to be
available, it¡¯s more a demand of being synchronized (so it¡¯s
statistically better to get the average of 5 good numbers rather
than 50 marginal numbers). And (for me the best part) you really
can employ an A/D with synchronized S/H for good coordinated
forward and reverse power.
I really don¡¯t think anyone here (other than me) will ever do it
this way. Just indicating reverse power by some cheap method is
probably fine for tuning an antenna.
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<#m_7015192241025951502_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
|
Off topic: Duwayne on QSO Today
I think that this one deserves an exception. I hope the moderators agree :
DuWayne, KV4QB, our fellow here in the group. He is an amazing homebrewer who has done some really original work. We met online a few years ago on the Minima llist.?
He has been featured on the QSO Today. His story is inspiring and educational for me.?
- f
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Re: ND6T AGC implementation for uBIT-X
Kees,
Thanks.? Found the files.? ?I have done a lot of SMT so looking forward to the boards to play with.
SWR/Wattmeter would be great especially if small enough to integrate in the uBitX box.
Thanks for all your hard work, and i am sure the entire group, appreciates it.
Thanks again,
Gene N2IJF
toggle quoted message
Show quoted text
Gene,
Sorry about the confusion.
The QSL.net website does not have a files section The first link you listed gave you my general website discussing ham radio and the last section gives the link to the kits I'm presently offering, that's the second link you listed. Nothing having to do with
uBITX is on that website at this time.
All my uBITX stuff is presently on this website in the "Files" section under my call? K5BCQ? and the projected demand for the AGC kit and Click kit are pretty high .......but beware that it's small SMT stuff and you might have to enlist younger eyes and hands
to help out. I just take it nice and slow.......
I'll update it as needed.
After the AGC and Click board demand subsides (this Topic), I was tossing out a few other options like some kind of mWattmeter for the uBITX and looking for input. Apparently there is a lot of interest and various implementation opinions there too. I'm listening
and have built mWattmeter kits before using forward biased, matched HSMS-2815 diodes, and was thinking of AD8307 parts since they are now so inexpensive (not so 10 years ago).
73 Kees K5BCQ
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Re: ND6T AGC implementation for uBIT-X
I would like to obtain both the AGC and Click kits.?
Thanks
73, Paul, KA5BIW?
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Figured it out.
?I have been running my uBitx with KD8CEC's firmware and have been particularly happy with his SDR adaptation. However, it really bugged me that I could only see a very small amount of bandwidth at a time when using the tap off of the IF.
So, I added my upconverter inside the ubitx, put in a 5 volt power supply for it, and tapped the antenna directly on the output of K3. The end result is seen below. The first pic shows what I saw using the IF tap, a very small portion of the 80meter band around the tuned frequency. The second shows the entire 40 meter band! In order to do this, only one change was needed on the SDR software, in the external radio settings there is an option to run sharing the antenna rather than using the IF. KG4GEK Greg
On Sun, May 6, 2018 at 7:01 PM Dexter N Muir < dexy@...> wrote: Data sheets specify "viewed from below", usual convention is to view from above. In between comes mirror-imaging horizontally and vertically. It's a mess. Definitively, with device in hand, view as if you're plugging it into a PCB (i.e. view from above). Now the two 'end' pins with greater gap to the rest are pins 8 and 9, the coil. The imagined IC 'notch' is the other end.
Hopefully helpfully
Dex, ZL2DEX
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Re: ND6T AGC implementation for uBIT-X
If you're only looking at reflected power and it's flat you don't know if you have a good swr or the radio isn't putting out. Now if you're also looking at forward power, the mystery is solved.
Vince.
toggle quoted message
Show quoted text
On 05/06/2018 07:59 PM, Tim Gorman wrote: A simple measure of reverse power will tell you if the antenna is
working ok.
--
Michigan VHF Corp.
|
Braces or brackets? Braces mark statement/function blocks while brackets are most often used with array sizes. The old K&R style was to leave the opening brace on the same line as the expression block, and then align the closing brace with the expression block start. I think that was done to get more lines on the screen when a 25 line display was common. Today, most seem to place the opening brace on its own line. If the block spans more than a page, the latest IDE shows the opening expression. You can also use Ctrl-T to format your code to a common C coding style.
Jack, W8TEE
On Sunday, May 6, 2018, 7:27:08 PM EDT, Michael Monteith via Groups.Io <michael_r_monteith@...> wrote:
?I definitely put brackets on the following lines.? In particular a lot of IDEs and even a lot of editors will do matching brackets for you.? In that case you can see quickly where the begin and end are.?? On some of them they have vertical ghost tab lines and easy to look up and down and see where the align.? Not to mention if you forget one it's easy to track back.?
?Michael
KM4OLT
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Re: ND6T AGC implementation for uBIT-X
So what would be the minimum compute requirement on an existing Nano ? Maybe read 2 analog inputs directly from 2 AD8307s? with only a scaling factor for Stockton Bridge coupler loss. Multiply that by 1dBm per 25mV (linear spec for the AD8307) and you have the Forward and Reflected power in dBm into a 50 ohm load.? Look up the "power" in Watts or tape a small chart on the bottom of the uBITX.
73 Kees K5BCQ
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Re: ND6T AGC implementation for uBIT-X
There are times when I'd like to know if the rig is working.?
toggle quoted message
Show quoted text
On Sun, May 6, 2018 at 04:59 pm, Tim Gorman wrote:
Forward power, and using it to calculate SWR, tells you more about how
your rig is operating then about the match to the antenna.
|
Re: ND6T AGC implementation for uBIT-X
I guess then to take it a step further, all you need is the reverse line section, a diode, a couple of RF blocking capacitors, a resistor, and an LED. LED blinks when there is reverse power. You could make that for less than $1.
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ
Owner - Operator
Big Signal Ranch ¨C K9ZC
Staunton, Illinois
Owner ¨C Operator
Villa Grand Piton ¨C J68HZ
Soufriere, St. Lucia W.I.
Rent it: www.VillaGrandPiton.com
Like us on Facebook!
Moderator ¨C North American QRO Group at Groups.IO.
email: bill@...
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Tim Gorman Sent: Sunday, May 6, 2018 7:00 PM To: [email protected]Subject: Re: [BITX20] ND6T AGC implementation for uBIT-X A simple measure of reverse power will tell you if the antenna is working ok. Forward power, and using it to calculate SWR, tells you more about how your rig is operating then about the match to the antenna. If you have a perfect match, i.e. no reverse power, then it doesn't matter what your forward power is as far as the antenna match is concerned. The SWR will always reduce to (1 + sqrt 0)/(1 - sqrt 0) or 1:1. I'm not arguing that it isn't nice to know your forward power and/or swr, I'm just saying it isn't necessary for operation of the ubitx. In fact, knowing your forward power is a nice diagnostic tool to have handy. But only reverse power is necessary to make the overall system work as well as possible. The ubitx code has gotten so large that it's almost necessary to drop something in order to add something. It's why people are looking toward processors with more memory available. I just want to add what is essential, not what is "nice". tim ab0wr On Sun, 06 May 2018 14:31:41 -0700 "Jerry Gaffke via Groups.Io" <jgaffke@...> wrote: For portable ops, I use a resonant antenna.
Does not need a tuner.
But I still want to know if it's working properly.
Jerry
On Sun, May 6, 2018 at 01:24 pm, Tim Gorman wrote:
You still need an antenna tuner. The SWR meter is kind of useless
without one.
I'm want to be able to operate for at least 48-72 hours. I'm
figuring you need at least a 36-50 amp-hour battery to be
self-sufficient.
--- This email has been checked for viruses by AVG.
|
Re: ND6T AGC implementation for uBIT-X
A simple measure of reverse power will tell you if the antenna is working ok. Forward power, and using it to calculate SWR, tells you more about how your rig is operating then about the match to the antenna. If you have a perfect match, i.e. no reverse power, then it doesn't matter what your forward power is as far as the antenna match is concerned. The SWR will always reduce to (1 + sqrt 0)/(1 - sqrt 0) or 1:1. I'm not arguing that it isn't nice to know your forward power and/or swr, I'm just saying it isn't necessary for operation of the ubitx. In fact, knowing your forward power is a nice diagnostic tool to have handy. But only reverse power is necessary to make the overall system work as well as possible. The ubitx code has gotten so large that it's almost necessary to drop something in order to add something. It's why people are looking toward processors with more memory available. I just want to add what is essential, not what is "nice". tim ab0wr On Sun, 06 May 2018 14:31:41 -0700 "Jerry Gaffke via Groups.Io" <jgaffke@...> wrote: For portable ops, I use a resonant antenna.
Does not need a tuner.
But I still want to know if it's working properly.
?
Jerry
On Sun, May 6, 2018 at 01:24 pm, Tim Gorman wrote:
You still need an antenna tuner. The SWR meter is kind of useless
without one.
I'm want to be able to operate for at least 48-72 hours. I'm
figuring you need at least a 36-50 amp-hour battery to be
self-sufficient.
|
Re: BITX QSO Afternoon/Evening, Sunday, May 6, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.
Thanks Stan WS4JM in TN for the shout. Look for you guys on wed night same place and time. Going to be an early night for me...busy weekend.
73 Tom VE3THR
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Re: BITX QSO Afternoon/Evening, Sunday, May 6, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.
Good to work you again John WA2FZW. Also worked Marc N4DR and Bruce KC1FSZ. Marc got his BITX40 tuned up now on frequency? - sounds great! My uBITX is alive! 1st time on the air with it tonight. Lots of static crashes but sigs are readable. Listening along for a while on 7.277 MHz.
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Re: BITX QSO Afternoon/Evening, Sunday, May 6, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.
Heard Tom in Ontario and Mark in MD but I couldn't get back to either.
73 de WS4JM
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?I definitely put brackets on the following lines.? In particular a lot of IDEs and even a lot of editors will do matching brackets for you.? In that case you can see quickly where the begin and end are.?? On some of them they have vertical ghost tab lines and easy to look up and down and see where the align.? Not to mention if you forget one it's easy to track back.?
?Michael
KM4OLT
|
K9HZ
Jay - WS4JM
Michael Monteith