Date   

Re: Replacement part for IC4 #fst3253

Wes AE6ZM
 

Miracles of miracles! Thanks to Jim K8IQY who noticed Mouser is now showing a large stock of the SOIC. When I checked them earlier today they showed no stock at all for the ..MX part. I am ordering a bag. 
Thanks again to all who offered help. Great community here.
--
> I finally got it all together...now I can't remember where I put it<

VY 73,
Wes

AE6ZM

Sierra Vista, AZ

 


Re: For Sale: QCX + Enclosure + QLG1

k7pi <exbpi@...>
 

The QCX package has been sold.  Thank You


Re: New 20 Meter QCX failure

Floyd Abrames
 

Thanks Alan
I clipped pin 8 and the 1 ohm to ground is in the IC.   
still had 13 ohms to ground on vcc.  Pulled IC2  from socket 
ohms to ground now 320K.  Looks like I need ICs 2 and 3 both.
Just wish I knew why the failures,Thanks again for your input.
73
Floyd AA0GU


Re: Replacement part for IC4 #fst3253

Wes AE6ZM
 

Thanks to all for the suggestions. This unit took some kind of hit, the 74ACT00 was shorted, along with several other components damaged. I cut the 5V trace right at the last via to the VCC pin on the 3253, so it was tested completely isolated from the circuit. To quell all worries, I have been working the service bench since 1969. SMD repair is a pain, but thank goodness for magnifiers!!! If I can get a new part I will cut this old one out pin by pin.
Now what would be of greatest help is if someone has a source for the SOIC 3253. Hate have to send this unit back to the owner as a transmitter only.
--
> I finally got it all together...now I can't remember where I put it<

VY 73,
Wes

AE6ZM

Sierra Vista, AZ

 


Re: Should we have a QCX QSO Party? #qcx

N3MNT
 

Might be a good idea to do something similar to CWOPS weekly mini ( although not weekly) that operates early am, mid afternoon and late evening so that all band openings are covered. 


Re: Should we have a QCX QSO Party? #qcx

Harv - K2PI
 

I we foist this off on Hans, then we are doing it wrong.  I assumed a grassroots effort. 

Once a month seems too much for a QSO party, but once a month for a "rally", of perhaps two morning and two evening hours might be useful.  This provides an opportunity for new builders to put their rigs on the air and give them a real workout, while at the same time giving an incentive for others to work them through scoring arrangements.  Maybe that's the monthly event we are all looking for?
--
Harv
K2PI
Warrenton, VA


Re: ProgRock register report broken

geoff M0ORE
 

Don't know if you have sorted this problem yet.

Looking at the file you posted first, it looks to me as if you have not got the CR+LF set which you confirmed in your second post.

Have you tried using TeraTerm to communicate with the device set up exactly as the screenshot at bottom of page 7?

Another possibility is the deleting of typos, see warning note on page 10.

As I said earlier, I used the serial port exclusively for programming mine and never had an issue. I tweaked register 2 for the crystal frequency many, many times, often 1Hz at a time to get it right.

You could try setting back to factory default to see if that clears anything. Not certain what the setting of register 28 to 0 would cause. Para 4.5 on page 13 refers.

Still waiting for my replacement device to pop through the letter box. Apparently it is in the UK somewhere.

Geoff

On 2/3/2019 11:42 PM, entilleser via Groups.Io wrote:
Some further investigation:  after setting all registers from 4 - 28 to 0, I began running successive register reports, adding a single digit to the value of register 4 prior to each report, i.e. 1, then 11, then 111, et cetera.  With the exception of the first report, with register 4 containing "1", the breakdown in the register report moved "up" with each successive report - that is, the breakdown appears to be dependent on the number of characters sent, the more characters sent in the early part of the report, the fewer characters are correctly transmitted toward the end.

Like this:
(registers 0-3 as normal)
4:1
5:0
6:0
...
11:0
12:0
13.0
garbage

then
(registers 0-3 as normal)
4:11
5:0
6:0
...
11:0
12:0
garbage


Re: Replacement part for IC4 #fst3253

Steven Weber
 

If It were drawing excessive current, it would be getting very, very hot to the touch.

 

Make sure the 74AC00 is installed in the correct direction.

 

Soldering issues are by far the most common reason a kit does not function. Rarely is it a bad part, in fact it’s almost unheard of. You have to work really, really hard to damage a modern IC. Reverse supply polarity will kill a lot of ICs’ but not always. They usually survive being in the wrong way around.

 

I sure hope you don’t have to change out IC4, that will not be easy.

 

73, Steve KD1JV

 

 

>and it appears that IC4 is drawing excess current. Static

> measurement shows ~140 ohms VCC to ground. Everything else checks OK on

> the 5V bus.

 

Wes,

 

Before replacing anything be completely sure.

Most faults are solder whiskers, if it was like it from the start even

an unetched piece of copper, component failure is unusual except when

stressed.

A test is to gently lift pin 16 with a pin.

 

73 Alan G4ZFQ

 

 

 


For Sale: QCX + Enclosure + QLG1

k7pi <exbpi@...>
 

I have for sale an unpackaged 20m QCX kit (board version 2.0), unpackaged QCX enclosure, and an unpackaged QLG1 GPS for sale to a US buyer. Current price for the three units from QRP Labs (enclosure now only available from supplier) is $109 plus shipping costs. I will sell the package for $75 shipped USPS priority mail. Pictures available on request. Payment via PayPal or personal check.

Contact Mike, K7PI at exbpi@...


Re: Should we have a QCX QSO Party? #qcx

R.Putnam
 

I have thought along these lines for ages i just worry that Hans has enough on his plate already. Any key any power just log your QSO's. Just getting  us all on the air at the same time will be enough of an achievement!

Richard G0ILN. 


Re: Replacement part for IC4 #fst3253

Alan G4ZFQ
 

and it appears that IC4 is drawing excess current. Static measurement shows ~140 ohms VCC to ground. Everything else checks OK on the 5V bus.
Wes,

Before replacing anything be completely sure.
Most faults are solder whiskers, if it was like it from the start even an unetched piece of copper, component failure is unusual except when stressed.
A test is to gently lift pin 16 with a pin.

73 Alan G4ZFQ


Re: New 20 Meter QCX failure

Alan G4ZFQ
 

  I found resistance from 5volt supply to ground to be 14 ohms and pin 8 of IC3 was 1 ohm to ground.
Floyd,

Before replacing anything be completely sure.
Most faults are solder whiskers, component failure is unusual except when stressed.
If you are sure it is IC3 then snip just pin 14 to confirm.

73 Alan G4ZFQ


Replacement part for IC4 #fst3253

Wes AE6ZM
 

Has anyone found a source for the SOIC footprint version of IC4, the FST3253? I have a unit on the bench with overheating of the 5v regulator, and it appears that IC4 is drawing excess current. Static measurement shows ~140 ohms VCC to ground. Everything else checks OK on the 5V bus. 
--
> I finally got it all together...now I can't remember where I put it<

VY 73,
Wes

AE6ZM

Sierra Vista, AZ

 


New 20 Meter QCX failure

Floyd Abrames
 

My recently finished QCX 20 failed after maybe 30 minutes of use.  The only problem at that time was the common one of low power.  I was studying the testing procedures when the lcd display went blank.  I happened to touch the 7805 voltage regulator and it was extremely hot.  I took power off immediately.  No smoke or burned smell. I put a ampmeter in line and added power just long enough to get a reading which was 600ma.  Not wanting to burn up the 7805 I did some checking power off.  I found resistance from 5volt supply to ground to be 14 ohms and pin 8 of IC3 was 1 ohm to ground.  Pin 8 has a short lead to R43 {120K).  I looks to me that IC3 has failed internally. IC2 controls the lcd so it may have died.  The lcd was checked on an arduino and is ok.  I hate to change IC3 but looks like the best starting place.
I can find no supplier for the 74ACT00N.  Any help?  Any disagreement with my logic?  
Thanks for any help

Floyd AA0GU


Re: 2 x 20m WSPR/QRSS balloons launched back to back

Jim .....
 

WD4AH was receiving both payloads well today.
No GPS put one transmitter nearly right on top of the other when it should have a 2 minute separation.
Interesting to say the least but at least they are seen.


Re: 2 x 20m WSPR/QRSS balloons launched back to back

Jim .....
 

Both flights are identical...too bad the GPS is not working on the first that was released,but knowing where the second one is will give a clue if they are heard tomorrow.
Few spots all day today as the drift is way too bad for solid decodes.Trying to read the QRSS is nearly impossible or could see new grid and altitudes.
Not too sure what caused these to work so bad and sticking to poor quality supplies or mislabeled values.
Google APRS is using what little data it can get to show where it is.
So it did ok,certainly not a race -
https://aprs.fi/#!mt=roadmap&z=7&call=a%2FG0UPL-11&timerange=86400&tail=86400
The first should be an hour ahead or so.
I saw both signals on various remote SDR receivers.
Will see if they show up tomorrow.
List of spotters and altitudes...not too many but better than none -




Re: QCX-SSB: SSB with your QCX transceiver

jjpurdum
 

The Teensy 3.5 and 3.6 have floating point processors which might help.

Jack, W8TEE

On Monday, February 4, 2019, 2:01:11 PM EST, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:


Most of the computations are in 32 bit floating point.
Doesn't really matter that it's an 8 bit CPU if the computations can be carried out
at the required 8khz rate.
 
Primary limitation I see is the speed and accuracy with with it can convey those computations
to the modulator and the si5351.

Don't have a QCX, experimenting on an ATMega328P would be limiting..
May try moving it to a Teensy 3.2 and an Si5351 breakout board.
See how fast I can wind up those i2c writes.

> Multibyte writes just take longer.

He's getting by with just 7 bytes over the i2c bus per update.
That's device id,  register address, and 5 multisynth registers.
I doubt there's any way to reduce it.

Jerry, KE7ER
 


On Mon, Feb 4, 2019 at 09:16 AM, ajparent1/KB1GMX wrote:
The problem is not that alone.  This design gets a amazing about from the 16mhz 8 bit CPU.
When you round the results to 8bits you get truncation and rounding errors so 1/256 is not
a great number if it translates to a DB value of distortion for amplitude, phase, or even time.
You can throw a fast 32bit cpu against it but many of the non digital external analog functions
are still there to cause or add distortion.

There is little question in my mind that its optimized.  I've spent a bit of time with the
code already.  Its very dense as there are multiple processes going on.

This type of technology is resistant to just throwing stuff at it in the hopes of making it better.
The often result of that is makes it worse.   Takes a very system view to get to better and 
also what you need to get there.


Re: QCX-SSB: SSB with your QCX transceiver

Jerry Gaffke
 

Most of the computations are in 32 bit floating point.
Doesn't really matter that it's an 8 bit CPU if the computations can be carried out
at the required 8khz rate.
 
Primary limitation I see is the speed and accuracy with with it can convey those computations
to the modulator and the si5351.

Don't have a QCX, experimenting on an ATMega328P would be limiting..
May try moving it to a Teensy 3.2 and an Si5351 breakout board.
See how fast I can wind up those i2c writes.

> Multibyte writes just take longer.

He's getting by with just 7 bytes over the i2c bus per update.
That's device id,  register address, and 5 multisynth registers.
I doubt there's any way to reduce it.

Jerry, KE7ER
 


On Mon, Feb 4, 2019 at 09:16 AM, ajparent1/KB1GMX wrote:
The problem is not that alone.  This design gets a amazing about from the 16mhz 8 bit CPU.
When you round the results to 8bits you get truncation and rounding errors so 1/256 is not
a great number if it translates to a DB value of distortion for amplitude, phase, or even time.
You can throw a fast 32bit cpu against it but many of the non digital external analog functions
are still there to cause or add distortion.

There is little question in my mind that its optimized.  I've spent a bit of time with the
code already.  Its very dense as there are multiple processes going on.

This type of technology is resistant to just throwing stuff at it in the hopes of making it better.
The often result of that is makes it worse.   Takes a very system view to get to better and 
also what you need to get there.


Re: QCX-SSB: SSB with your QCX transceiver

Jerry Gaffke
 

Yes, more jitter with fractional output dividers, but not as much as you might think.
If we mostly care about maintaining RF phase accuracy over millisecond long intervals,
then we may be better off with the output multisynth dividers.

Looking at datasheets for other members of the Si53** family, the extra jitter is less than a factor of two.
They do this by using programmable delay lines, and digitally computing an appropriate delay
for each rising and falling edge to correct the dirt created by bouncing between two different 
divider values.

But that "less than a factor of two" is mostly a guess till somebody measures jitter for
the specific code being used at a large collection of target frequencies, not just one or two.
Especially since ClockBuilderPro software from SiLabs does all sorts of undocumented tricks.

My guess is  jitter will not be a problem.
Nobody's mentioned an issue with phase noise on the uBitx, and that uses output multisynth dividers.
Abrupt small changes in frequency are probably ok, the clock pulse at the moment of transition
from the output multisynth divider is indistinguishable from its neighbors on a scope,
But if we are doing updates at only 8khz, those frequency changes could be large enough
to cause trouble.

Jerry


On Mon, Feb 4, 2019 at 09:02 AM, ajparent1/KB1GMX wrote:
Going fractional creates jitter ass to the phase noise spectra.


Re: 2 x 20m WSPR/QRSS balloons launched back to back

Curt M.
 

This is pretty cool to watch.  Looks like maybe it's getting tossed around up there and not making a little bit of progress.