Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
- QRPLabs
- Messages
Search
|
1pps and LED trick..
"andyfoad@..."
I didn't comment at the time because I haven't tried it, but yourI suppose there is only one way to find out. Plonk an LED On the output via a 2k2 and see what happens ;-) On my UP501 module I intended to have an LED connected all the time but it loaded it sufficiently to stop the U1/U2 from seeing the pulses so I decided on option 2. Use a push to make button on my GPS box as a simple way to test that the GPS had acquired satellite data and was working. Otherwise I was forever working blind. From a cold start I usually have to wait about 10 mins for the GPS to sort itself out. I just push the little button every few minutes to see if it's got a lock. Once my green led start blinking I release the button to take it back out of circuit and then switch on the U1/U2 and let it all fly. So simple, yet so useful. 73 de Andy |
|
Re: v2.02k - Twice the fun, WSPR and QRSS together!
Keith Maton
¿ªÔÆÌåÓýEddie, Two showers and a train journey and Hans will have worked it out. 73 Keith, G6NHU |
|
Re: Those GPS 1pps problems. (Some bystander thoughts)
dean smith
I second FTD,s remarks on the reyax UP501 modules... Faultless.. Plug n play ;-)
|
|
Re: Those GPS 1pps problems. (Some bystander thoughts)
"David Atkins"
I tried a pulse-stretcher using a 555 [found on the net, not my design] with
toggle quoted message
Show quoted text
both a Trimble unit and a Sure development board. Neither of them had any success ;-( OTOH, the 555 isn't the best chip to use for this job. I just happened to have some in the junk-box. Anyway, I've ordered new processors for my Ultimates, so I hope my problems will be behind me soon. By the way, I want to use my Ultimates as portable units. Having a separate antenna makes it possible to put the transmitter in a strong metal box, but nearly all the 'recommended' GPS units appear to have integrated antennas which need delicate surgery to the case and make waterproofing more difficult. Any thoughts on that? David G8XBZ -----Original Message-----
From: QRPLabs@... [mailto:QRPLabs@...] On Behalf Of andyfoad@... Sent: 16 June 2013 10:05 To: QRPLabs@... Subject: [QRPLabs] Those GPS 1pps problems. (Some bystander thoughts) Yesterday I thought I'd try to do a bit of research regarding the GPS modules used by kit owners. Now I'm not sure if I've got all the model numbers correct but from what I've seen so far, all the modules have a very narrow 1pps width output. For example I've seen figures of nanoseconds and microseconds quoted on the troublesome modules, yet my Reyax UP501 which works flawlessly has a whole 100ms width for the 1pps output. From where I am standing it does seem that this pulse width is the key to it all. I remember some month ago some work by KA7OEI regarding using and RC network across the 1pps outputs might help broaden the pulses to work. Maybe a trawl through this groups archive might reveal some more ? Just thinking aloud... 73 de Andy G0FTD (Reyax UP501 GPS user with zero hassles) |
|
Re: Those GPS 1pps problems. (Some bystander thoughts)
Hans Summers
Hi Eddie, Andy Thanks for the thoughts on this. This is the next challenge - to make the GPS Interface work with both very short, and very long pulses.
I don't know if I mentioned it before, But I have what I call a "GPS simulator" which I use for testing such things. It basically is an ATmega168 (the same chip) programmed to produce a $GPRMC sentence and code the time and location into it, and a 1pps signal. It also has a button to toggle the GPS on/off which can simulate the effect of disconnecting it or it losing satellite lock. I am able to adjust the pulse-width in this "simulator". So with sufficient effort, I ought to be able to model the Trimble and the Rayax 501 and produce code which works with both of them, even though I physically own neither.
I believe the Rayax 501 worked with both U1 and U2 v2.01 and v2.02. So it is as Andy says - GPS modules with the very short pulse times seem to be the challenge.? 73 Hans G0UPL On Sun, Jun 16, 2013 at 10:33 AM, g3zjo <g3zjo@...> wrote:
|
|
Re: v2.02k - Twice the fun, WSPR and QRSS together!
Hans Summers
Hi Eddie No, I didn't put it into the spare bytes! I removed the Hell modes from v2.02k to make space. Hell takes a lot of space in the memory because it's a huge look-up table for all the character definitions. Some day if I really wanted to pretend to be smart, I should see if I could make a data compression algorithm to make that character table fit in less space. I should give that some thought...
73 Hans G0UPL On Sun, Jun 16, 2013 at 9:24 AM, g3zjo <g3zjo@...> wrote:
|
|
Re: Those GPS 1pps problems. (Some bystander thoughts)
g3zjo
On 16/06/2013 10:04, andyfoad@... wrote:
For example I've seen figures of nanoseconds and microseconds quoted onAndy Did the Rayax work on v2.01 The 1pps pulse width does seem to be tied up with the claimed accuracy for for timing / frequency purposes. Hans obviously knows how to handle long and short versions, a mid way compromise seems to be needed, if v2.01 had not got it right for the Trimble I may have been thinking about adding a Schmitt Trigger. Hans was still exuding confidence on a solution last time we spoke on the subject. I didn't comment at the time because I haven't tried it, but your tip of using an LED to detect the PPS signal I am fairly sure would not work on the Trimble GPS, its too quick for the Scope so I don't think the eye would catch it. 73 Eddie |
|
Re: v2.02 released
Hans Summers
Thanks Eddie & Andy I'm all blushing now... 73 Hans?
|
|
Those GPS 1pps problems. (Some bystander thoughts)
"andyfoad@..."
Yesterday I thought I'd try to do a bit of research regarding the
GPS modules used by kit owners. Now I'm not sure if I've got all the model numbers correct but from what I've seen so far, all the modules have a very narrow 1pps width output. For example I've seen figures of nanoseconds and microseconds quoted on the troublesome modules, yet my Reyax UP501 which works flawlessly has a whole 100ms width for the 1pps output. From where I am standing it does seem that this pulse width is the key to it all. I remember some month ago some work by KA7OEI regarding using and RC network across the 1pps outputs might help broaden the pulses to work. Maybe a trawl through this groups archive might reveal some more ? Just thinking aloud... 73 de Andy G0FTD (Reyax UP501 GPS user with zero hassles) |
|
Re: v2.02k - Twice the fun, WSPR and QRSS together!
Keith Maton
¿ªÔÆÌåÓýThis is the upgrade I'm most excited about!Once the Martello Tower Group have received their 2.02k version, we will be installing it into G0PKT and running both WSPR and QRSS on 30m and setting up a second station on 10m doing the same thing. Thanks for the work you've put into this update and the new customised version, Hans. 73 Keith, G6NHU On 16 Jun 2013, at 06:35, Hans Summers <hans.summers@...> wrote:
|
|
Re: v2.02 released
g3zjo
On 16/06/2013 06:32, Hans Summers wrote:
Thanks for waiting patiently. The new v2.02a version is now officially releasedHi All I recommend v2.02a be rapidly installed in all v2.01 U2's. It really is good. The improvements in spectral purity are outstanding and some of the operating convenience improvements well worth while. I have tested WSPR15 successfully on 474kHz with reports down to -40dB . I am sure no one would want to still run v2.01 once they have compared the results. Thanks Hans for your work. As Hans says there is still the issue with the Trimble GPS which worked fine on v2.01, so the rule for the moment is, don't go for the Trimble if you have got to get a GPS, if you don't want to run a GPS then v2.02a is the bees knees. 73 Eddie G3ZJO |
|
Re: v2.02k - Twice the fun, WSPR and QRSS together!
g3zjo
On 16/06/2013 06:35, Hans Summers wrote:
The intended use, is to send WSPR for 2 minutes, followed by 8 minutes of FSK/CW (or other mode).Hi Hans That's great, exactly what my PIC DDS MEPT does, shown on Knights Frequency Table as 8minutes QRSS, 2miinutes to commune with Satan. I knew you would manage to do something with those few left over bytes. 73 Eddie G3ZJO |
|
Ultimate2 kit status
Hans Summers
All An update on where I am with the next batch of U2 kits, which I had hoped to have ready near the start of June, but clearly that was over-optimistic.?
Firstly the PCB manufacturer claims a 1 week manufacture time but the reality seems more like 5-6 weeks overall and I am still waiting :-( ?I'm sure you'll agree, the boards are excellent quality and the cost is reasonable. But what they are NOT, is fast.
My DDS module supplier changed the 125MHz canned crystal oscillator to a surface mount device, and told me AFTER I'd paid, then wouldn't refund. Insisted on testing one sample module to make sure they were still suitable for QRSS. They are. So no problems, other than the delay.
Reliability-wise, of the original batch of 200 DDS modules, I tested every single one to make sure that every kit builder gets a working DDS module. 29 were found to be faulty or insufficiently stable for QRSS use (a 15% failure ratio). The new batch of 200 have about 10% failures in testing.?
Anyway the end result is that once the new batch of 200 DDS modules had finally arrived and been tested, I found that I had enough of everything to put together 25 more U2 kits. These will ship from the distributor tomorrow (Monday). So the first 25 on the waiting list should be sorted.?
For everyone else, I'm sorry but there's nothing I can do but wait :-( ? All this sending stuff all over the world takes time. As soon as the PCB's get here then I should be able to get everything moving.?
73 Hans G0UPL |
|
60m filter available
Hans Summers
All Following Andy's design (see pasted below), I have now added a 60m filter to the kit shop?
73 Hans G0UPL http:/ DESIGN:
Just been playing here with a design for the?60m?band which may be of use to U2'ers, or Hans if he's requiring a?60m?LPF design. Take one of the 80m LPF's. L1 = 23 TURNS (WAS 25) L2 = 24 TURNS (WAS 27) L3 = 23 TURNS (WAS 25) Change C1 and C4 change to 680pf C2 and C3 remain at 1200pf. So all you really need in terms of new components are 2 x 680pf caps! 1st harmonic is -58db down 2nd harmonic is -79db down 73 de Andy G0FTD |
|
v2.02k - Twice the fun, WSPR and QRSS together!
Hans Summers
Good morning all, This is all the fault of Keith Maton G6NHU, who asked for a special version. Then we thought others might like it too. So that became v2.02k.?
It is based on v2.02 but the difference is, it ALWAYS sends a WSPR transmission in the first 2 minutes, followed by the selected QRSS mode. The intended use, is to send WSPR for 2 minutes, followed by 8 minutes of FSK/CW (or other mode). You have to use Frames in this version. They don't have to be 10 minutes, but need to be long enough to fit WSPR and your message, and if you are using GPS, you need 13 seconds free at the end of each frame to do the calibration.
This means you can play with WSPR, and QRSS modes, at the same time. You can select a different frequency for the WSPR transmission and the FSK/CW (or other QRSS mode) transmission.
The summary of the "version k" is here??and you can also download its own operating manual, specific to this version, which details all the differences.
If you want, you can buy this version of the chip here?
73 Hans G0UPL |
to navigate to use esc to dismiss