Date   

Re: Weird WSPR decode anomaly - Probably a FEC problem with wspr decoding software

Alan G4ZFQ
 

Ron Carr wrote:
The receiving software keeps a database that it uses to match complex calls and 6 character grid squares to the correct call.  And the matching algorithm is not perfect as I believe it uses a hash or similar scheme.  I could see something like this happening if you or he used a call like  K1URC/3   or a grid like FN54fk.
Tony,

Yes, some decodes are difficult or impossible to fathom. Due to the hashtable feature complex calls are suspect and best not used if not really required.
Was there a complex call involved?
You did the right thing, check how many others spotted the "transmission", whether propagation even was possible.
This one seems very strange but so do some other false decodes.

73 Alan G4ZFQ


Re: Weird WSPR decode anomaly - Probably a FEC problem with wspr decoding software

Hans Summers
 

Hi Ron, Tony

That is indeed a mystery. 

Ron, you are correct about 6-char grid squares in the extended WSPR transmission format - but the QCX is not capable of transmitting this extended format. It can only handle the simple normal WSPR transmissions. 

Tony, it cannot be a problem with Forward Error Correction because this relates to the encoding of the transmission itself, on the QCX. Forward Error Correction is, somewhat loosely, the term applied to the encoding of data with additional bits via the used encoding protocol, that allow the decoding station to correct errors in the transmission. The QCX cannot be transmitting or encoding your friend's callsign, since you have replaced it with your own. 

Furthermore it cannot be a problem with the QCX somehow remembering the encoding of your friend's callsign, since the encoded sequence of 162 symbols in a WSPR transmission is not stored in EEPROM, it is always calculated dynamically and exists in volatile RAM only. Therefore it is not persisted through power cycles. It is hard to see therefore, how this mystery could be caused by any problem in the QCX firmware itself. 

Some digital modes augment their decoding logic with a probability-based fuzzy match, looking for probable (but not algorithmically certain) matches between the decoded data, and a database of existing callsigns - which could be callsigns the decoding station has heard before, or in some cases an internet-based list of callsigns. This is a somewhat controversial practice, as far as I know it is not done in the WSJT-X software for WSPR at all; I know JT65 and Opera are two modes that use this controversial technique but I have not heard of it being applied to WSPR, though I could be wrong. 

All of which makes it a bit of a mystery... I do not see how this phenomenon could ever be caused by the QCX firmware itself, though equally well I don't see that it could be caused by WSJT-X either... unless there is some feature of WSJT-X I don't know of, or maybe there are other more aggressive WSPR decoder software packages out there which DO apply the controversial probability match. 

73 Hans G0UPL
http://qrp-labs.com

On Fri, Feb 26, 2021 at 12:53 PM Ron Carr <rcarr@...> wrote:
The receiving software keeps a database that it uses to match complex calls and 6 character grid squares to the correct call.  And the matching algorithm is not perfect as I believe it uses a hash or similar scheme.  I could see something like this happening if you or he used a call like  K1URC/3   or a grid like FN54fk.


Re: Weird WSPR decode anomaly - Probably a FEC problem with wspr decoding software

Ron Carr
 

The receiving software keeps a database that it uses to match complex calls and 6 character grid squares to the correct call.  And the matching algorithm is not perfect as I believe it uses a hash or similar scheme.  I could see something like this happening if you or he used a call like  K1URC/3   or a grid like FN54fk.


Re: Weird WSPR decode anomaly - Probably a FEC problem with wspr decoding software

tony.volpe.1951@...
 

I should have added that only 2 stations have 'spotted' these phantom 'transmissions' of the call. It isn't general at all.


QCX classic in QCX+ Case

m0icr@...
 

With apologies if this has already been answered elsewhere, but having conducted a search through group messages I failed to find the any comments on this topic.

I have a QCX classic which I am considering putting into a QCX+ case, I recognize I will need to connect the LCD and controls off board etc. 

I at not inclined for this QCX to be used in a BaMaTech case, as good as they are (and I have one for another QCX), I wish to put this radio in a 'vertical' type orientation).

Does anyone have any thoughts/experience of putting a QCX classic into a QCX+ case?

 

73, Carl M0ICR

 

 


Weird WSPR decode anomaly - Probably a FEC problem with wspr decoding software

tony.volpe.1951@...
 

A few days ago, I loaned one of my QCX radios to a mate so he could see how it worked. He is interested in starting WSPR himself and we programmed his call into my QCX40 classic and he ran it for a couple of days on a twenty minute frame setting.

I then got it back and  used it myself WITH MY CALL set up in it.

If I do a database search on his call, I still find a few current decodes which show his call, even though there were no transmissions with his call - only mine is in use. The wrong decodes are on the same frequency as mine with the same Maidenhead square and power. Is it possible that the Forward Error Correction at the receiving station is looking at other parts of the transmission and guessing a callsign the rx did not receive. I am absolutely certain that the call shown was not transmitted for the last two days.


Re: Setting time on QCX - wspr mode

Hans Summers
 

Hello Gerry
 
Thanks Alan for your reply. As I see it the 27mhz update from the GPS stream ensures an accurate transmission frequency. The 20mhz osc is updated by the GPS serial data stream (to quote
Hans from the manual) to ensure a stable time lock. I was just puzzling why if the 27mhz update is displayed, why is the 20mhz update not displayed also. Is this just a function of the QCX programme and it was never intended to display it? I know that the clock is in fact being updated as it is set accurately after the first WSPR transmission and I presume after each and every subsequent transmission.. 

The 20MHz crystal is not calibrated during the regular GPS calibration at the end of each WSPR transmission. Only the real time clock (RTC) is set. It is not necessary to calibrate the 20MHz crystal every time since any minor frequency deviation due to temperature drift will cause an irrelevant time shift during WSPR operation. 

20MHz crystal calibration using the GPS is possible in the alignment menu. It is enough to do this once when setting up the radio after assembly. It is not even necessary to do this, since even a few kHz of error will still have no important impact on timekeeping in the short-term (between RTC updates by the GPS at the end of each cycle). 

73 Hans G0UPL
http://qrp-labs.com


Re: tuners for experimental antennas and the QCX

ajparent1/KB1GMX
 

Hi Jim,

A long bunch of yeas back I did an 7x7 L tuner
with one switch and two rotary encoders.

I'd learned from Altair in early 75 that switch flipping was painful
so two 7 bit up down counters driving relays did the work.  Turn
the knob right and the C or L increases, to the left decreases.
Leds on each relay gave binary value of L or C.

A toggle selects what end the cap is at.  Works nice and 
is battery unfriendly as there can be 14 relays active at
40ma each. Usually about half were active.   This was
before cheap latching relays.  The companion MPU of the
day would have been 8748, or maybe the big gun 8751
both would have added power consumption.

A three knob Z tuner has the advantage of no batteries
or RFI.

Allison
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


Re: Setting time on QCX - wspr mode

Arv Evans
 

Geoff

I was proposing something a little different.  In QCX products frequency is
controlled by the SI5371a.  The 1-PPS is used for frequency or rate of
digital mode timing.  Maybe I misstated what I meant. 

If I can get all the ducks to stay in line, my alternative method of generating
the 1-PPS will be published in a few days (probably toward the 1st of next
month).

Arv
_._


On Thu, Feb 25, 2021 at 5:38 PM geoff M0ORE via groups.io <m0ore=tiscali.co.uk@groups.io> wrote:

I don't think the 20MHZ oscillator is controlled by the NEMA data from the GPS. The clock is maintained by the NEMA but that is not the same thing. If the NEMA is setting the clock time, the frequency of the 20MHz clock is not that important.

On 25/02/2021 20:30, Gerald Ball via groups.io wrote:
Thanks Alan for your reply. As I see it the 27mhz update from the GPS stream ensures an accurate transmission frequency. The 20mhz osc is updated by the GPS serial data stream (to quote 
Hans from the manual) to ensure a stable time lock. I was just puzzling why if the 27mhz update is displayed, why is the 20mhz update not displayed also. Is this just a function of the QCX programme and it was never intended to display it? I know that the clock is in fact being updated as it is set accurately after the first WSPR transmission and I presume after each and every subsequent transmission..  73 Gerry G4OJF
On 25 February 2021 at 17:15 Alan G4ZFQ <alan4alan@...> wrote:


This might suggest that the 20mhz osc 
is not being updated. 
Gerry

This has to be done manually. It just affects timekeeping without a GPS.
If you cannot measure it, check time drift and calculate.

73 Alan G4ZFQ






    


Re: Setting time on QCX - wspr mode

geoff M0ORE
 

I don't think the 20MHZ oscillator is controlled by the NEMA data from the GPS. The clock is maintained by the NEMA but that is not the same thing. If the NEMA is setting the clock time, the frequency of the 20MHz clock is not that important.

On 25/02/2021 20:30, Gerald Ball via groups.io wrote:
Thanks Alan for your reply. As I see it the 27mhz update from the GPS stream ensures an accurate transmission frequency. The 20mhz osc is updated by the GPS serial data stream (to quote 
Hans from the manual) to ensure a stable time lock. I was just puzzling why if the 27mhz update is displayed, why is the 20mhz update not displayed also. Is this just a function of the QCX programme and it was never intended to display it? I know that the clock is in fact being updated as it is set accurately after the first WSPR transmission and I presume after each and every subsequent transmission..  73 Gerry G4OJF
On 25 February 2021 at 17:15 Alan G4ZFQ <alan4alan@...> wrote:


This might suggest that the 20mhz osc 
is not being updated. 
Gerry

This has to be done manually. It just affects timekeeping without a GPS.
If you cannot measure it, check time drift and calculate.

73 Alan G4ZFQ







Re: Setting time on QCX - wspr mode

Arv Evans
 

If there was an alternative to generating one-PPS from GPS, and
if you could use CAT to send time and date and fixed location to
your QCX...would there be any need for a GPS.  Frequency
stability could be developed from the one-PPS, and for non-mobile
locations you would not need updatable latitude and longitude. 

Yes, thinking about this as a future project.  An accurate one-PPS
has already been demonstrated in my shop.  The rest is a to-be-coded
way to send the other data from my NTP synced PC and forward that
via CAT link.

Arv
_._


On Thu, Feb 25, 2021 at 1:30 PM Gerald Ball via groups.io <gerryball2=talktalk.net@groups.io> wrote:
Thanks Alan for your reply. As I see it the 27mhz update from the GPS stream ensures an accurate transmission frequency. The 20mhz osc is updated by the GPS serial data stream (to quote
Hans from the manual) to ensure a stable time lock. I was just puzzling why if the 27mhz update is displayed, why is the 20mhz update not displayed also. Is this just a function of the QCX programme and it was never intended to display it? I know that the clock is in fact being updated as it is set accurately after the first WSPR transmission and I presume after each and every subsequent transmission..  73 Gerry G4OJF
> On 25 February 2021 at 17:15 Alan G4ZFQ <alan4alan@...> wrote:
>
>
> >This might suggest that the 20mhz osc
> > is not being updated.
>
> Gerry
>
> This has to be done manually. It just affects timekeeping without a GPS.
> If you cannot measure it, check time drift and calculate.
>
> 73 Alan G4ZFQ
>
>
>
>
>


--
gerry






Re: #alignment #qcxmini #alignment #qcxmini

Robert Graf
 

Howdy! Replacing IC9 fixed the issue, the IC9 OPA2277U was indeed faulty. Now it's working. Cheers, -Robert K6RGG


Re: #u3s #troubleshooting No Spots / not sure transmitting #u3s #troubleshooting #help #lpf

GIUSEPPE
 


Il gio 25 feb 2021, 23:27 GIUSEPPE via groups.io <iw8rsb=gmail.com@groups.io> ha scritto:
hi Brad, hi Tony, it's always nice to know the lineages of your origins.  What makes me proud of being Italian and that wherever in the world you are, if you meet a person of Italian origins and understand him, he immediately starts talking to try to understand where he comes from, and then they treat us well in every place, we are unique  in terms of affection and friendship, I have several relatives in New York, children of my grandfather's sister, and cousins ​​of my maternal grandmother.  I remember years ago that I was talking on the 20m band and explaining the name of my country to an Italian radio amateur in Africa, Simeri Crichi, after a while he called a radio amateur from Canada saying he was from my own country.  Very happy, the world is small, and we radio amateurs listen and talk to each other in every corner of the world.  I hope that one day we will be able to do some qso to exchange a few words. Today the qcx mini kit arrived, as soon as it is assembled I will start working a bit in cw.  Thanks Brad and thanks Tony, it's time for me to go to sleep.  I work tomorrow.  good continuation.  73 iu8eun Joseph.

Il gio 25 feb 2021, 18:05 <tony.volpe.1951@...> ha scritto:
Brad said:

"Last, my great grandfather came to America from Lucca, Sicula in the late 1800’s.  I still have relatives there but have never been to visit.  Maybe some day.

73 Brad / K0WET"

Me too Brad - my great grandfather came to England with his wife in about 1895. They were very young at the time, I think about 18. They settled in London and now have many descendants  here and also in Australia - maybe further afield too for all I know. Anyway - I and my three sons and grandchildren are among them. 

I did go to Italy to see where they came from - a small town - village really in Latina between Rome and Naples. Other family members also have visited and made contact with living family members. There was even a very old man who could remember my great grandfather visiting as a very old man in the 1950s. 


Re: #u3s #troubleshooting No Spots / not sure transmitting #u3s #troubleshooting #help #lpf

GIUSEPPE
 

hi Brad, hi Tony, it's always nice to know the lineages of your origins.  What makes me proud of being Italian and that wherever in the world you are, if you meet a person of Italian origins and understand him, he immediately starts talking to try to understand where he comes from, and then they treat us well in every place, we are unique  in terms of affection and friendship, I have several relatives in New York, children of my grandfather's sister, and cousins ​​of my maternal grandmother.  I remember years ago that I was talking on the 20m band and explaining the name of my country to an Italian radio amateur in Africa, Simeri Crichi, after a while he called a radio amateur from Canada saying he was from my own country.  Very happy, the world is small, and we radio amateurs listen and talk to each other in every corner of the world.  I hope that one day we will be able to do some qso to exchange a few words. Today the qcx mini kit arrived, as soon as it is assembled I will start working a bit in cw.  Thanks Brad and thanks Tony, it's time for me to go to sleep.  I work tomorrow.  good continuation.  73 iu8eun Joseph.


Il gio 25 feb 2021, 18:05 <tony.volpe.1951@...> ha scritto:
Brad said:

"Last, my great grandfather came to America from Lucca, Sicula in the late 1800’s.  I still have relatives there but have never been to visit.  Maybe some day.

73 Brad / K0WET"

Me too Brad - my great grandfather came to England with his wife in about 1895. They were very young at the time, I think about 18. They settled in London and now have many descendants  here and also in Australia - maybe further afield too for all I know. Anyway - I and my three sons and grandchildren are among them. 

I did go to Italy to see where they came from - a small town - village really in Latina between Rome and Naples. Other family members also have visited and made contact with living family members. There was even a very old man who could remember my great grandfather visiting as a very old man in the 1950s. 


New QCX Mini

Jim Sheldon
 

The version 2 QCX Mini got here yesterday evening.  Built it today with absolutely no problems.  Went together in a reasonable amount of time (nowhere near as fast as Hans can build one) and all the alignments went without a hitch.  Used one of my QLG 1 GPS units to calibrate it and it's bang on according to my Elecraft K3S which is locked to a 10 MHz GPS disciplined oscillator so it don't get much better than that -- without tweaking the LPF toroids at all I'm getting 5.9 watts out of it into a Microwave Associates Dummy load according to my YouKits DP1 power/swr meter which has proven to be accurate within roughly 5% so I'm happy.  It's in the case and will go for it's first QSO later this evening or tomorrow morning depending on how many "honey do" jobs I've amassed whilst building it - LOL.

Nice job on the boards Hans - it didn't smoke and it went together nicely.  I didn't bother to look and see if Hans has posted a new manual for the V2 yet, the old one was sufficient.

Jim, W0EB


Re: Si5351A blown (IC1) QCX transceiver.

William Jenrick
 

Tnx Mont....If one doesn't want to spend their money for a Hot Air Station and rather spend their money on Hans,😁 I found this video helpful....

On Thu, Feb 25, 2021 at 8:24 AM Mont Pierce KM6WT <de.km6wt@...> wrote:
On Wed, Feb 24, 2021 at 10:52 PM, William Jenrick wrote:
Yes, I bought 5 of them for $.89/each but really don't know which is pin 1. The original one has a dot. So how does that correspond to the one pictured?
The beveled edge  indicate where Pin 1 is located.

With the beveled edge facing you (like your 2nd pic shows), the leftmost pin is pin 1. 



73,
km6wt



--
William Jenrick 


Re: Setting time on QCX - wspr mode

Gerald Ball
 

Thanks Alan for your reply. As I see it the 27mhz update from the GPS stream ensures an accurate transmission frequency. The 20mhz osc is updated by the GPS serial data stream (to quote
Hans from the manual) to ensure a stable time lock. I was just puzzling why if the 27mhz update is displayed, why is the 20mhz update not displayed also. Is this just a function of the QCX programme and it was never intended to display it? I know that the clock is in fact being updated as it is set accurately after the first WSPR transmission and I presume after each and every subsequent transmission.. 73 Gerry G4OJF

On 25 February 2021 at 17:15 Alan G4ZFQ <alan4alan@gmail.com> wrote:


This might suggest that the 20mhz osc
is not being updated.
Gerry

This has to be done manually. It just affects timekeeping without a GPS.
If you cannot measure it, check time drift and calculate.

73 Alan G4ZFQ




--
gerry


Re: New QCX Mini finally here

Gary Bernard
 

My QCX plus arrives today. Total shipping time, 7 days. Great job!!
Thanks Hans,
Gary W0CKI


-----Original Message-----
From: Russ@va3rr via groups.io <va3rr@...>
To: QRPLabs@groups.io
Sent: Thu, Feb 25, 2021 12:58 pm
Subject: Re: [QRPLabs] New QCX Mini finally here

Fearing exorbitant brokerage fees, my QCX Mini is at the mercy of the international postal system.  Last year, I ordered $10 worth of parts from Tayda, paid $11 in shipping via TNT, and Fedex wanted another $21 in brokerage fees/taxes when it arrived in VE3.  FML! I refused delivery.

I've already wound L1 to L4 in anticipation of my mini's arrival.

On Thu, Feb 25, 2021 at 01:49 PM, Bill Sanders wrote:
> I opened the box, but exercised extreme restraint and I will not open the
> individual packets until I am done with my previously scheduled workday!

If you do this, you won't be able to misplace parts and spend half the day wandering around the house wondering where you put them - hi!






Re: New QCX Mini finally here

va3rr
 

Fearing exorbitant brokerage fees, my QCX Mini is at the mercy of the international postal system. Last year, I ordered $10 worth of parts from Tayda, paid $11 in shipping via TNT, and Fedex wanted another $21 in brokerage fees/taxes when it arrived in VE3. FML! I refused delivery.

I've already wound L1 to L4 in anticipation of my mini's arrival.

On Thu, Feb 25, 2021 at 01:49 PM, Bill Sanders wrote:
I opened the box, but exercised extreme restraint and I will not open the
individual packets until I am done with my previously scheduled workday!
If you do this, you won't be able to misplace parts and spend half the day wandering around the house wondering where you put them - hi!


Re: Be careful !

Chris - KC0TKS
 

Chinesium, I love it!

My first wife was made of Chinesium. When she catastrophically failed, she only destroyed herself. Thank God I survived!


73, Chris - KC0TKS



On 2/25/21 1:08 PM, John wrote:
Made of finest Chinesium!

Glad you're mostly ok Paul, that had to really hurt.

John K5MO

5721 - 5740 of 68392