开云体育

I know a bit more than I did before. ?And, I'll dig into the site info to see if my old flakey gray matter can figure out how to connect it. ?Many thanks. ?

Hi Pete?

Will email you?

73 Gerry G4OJF?

--
gerry

Finishing up sharing this repair experience, not because I claim any great sherlock holmes detective ability, but in case it inspires anyone else like me who has been away from the hobby for a few decades and feels daunted by fault-finding on boards that are genuinely smaller because of surface mount components and seem smaller because, well, the eyes aren't quite what they used to be.

So having got the TX side going first, as suggested by Hans, I checked for DC continuity on the ICs where the trifilar transforer and L12 connect. All seemed OK. So I did a more thorough check of all the other receive components and sure enough:

?

IC10, the ADC, had a fleck of solder that must have either dropped off the iron or been picked up off the work surface

Once cleared I checked with an RF sweep again and all looked good

So three things I learned here. First up, like Hans' troubleshooting guide says, the chances are that if you're QDX isn't working it's really is likely to be a bad joint or a whisker of solder somewhere. Actually that's even true for my blown PA - I discovered a bad joint on my antenna feedpoint so that's what caused the SWR that blew up the BS170s that started me on this journey. Second, logical fault-finding from input to output still works just the same as it did 40 years ago. Finally, clean working conditions and scrupulous attention to detail on the board is really important in a way I don't remember it being 40 years ago and something like this gadget that I unexpectedly got from AliExpress for about $2 can reveal how truly gross and dirty things are down at the micro-level. I actually think 60X magnification is too much (hard to navigate on the board) but maybe 20X would be good:

Good luck if you are fault-finding on your QDX and I hope you have a good outcome as i did.

Hugh Mason 9V1SA

Hi Gerry, I have one spare. Nearly new (some dust hi) with all the knobs & extenders, buttons etc. Only 2 machine screws missing, 3mm I think. Purchased from BMA Tech in 2019, ?34.50.
Are you anywhere near Cheltenham? I'd like 1/2 cost.
73 Pete G4IOA

Hi Peter

Thanks for the link.

73 Gerry G4OJF?

--
gerry

Here one is offered but its in DL:



I am not the seller!

73!
Peter DL3NAA

Don,

Thanks for the checking and the feedback Ron!

Reassuring to know that that this rig is operating as expected.. It does have the TXCO and used to have the AGC but I removed it to check the op amps underneath. I may put it back at some point.

I consider my question answered and I'm satisfied.

-mike/w1mt

Hi Mike,

I just checked my 40 meter QCX-mini connected to a 50 ohm dummy load and I do in fact hear spurious signal on 7.052.00 and 7,143.65 MHz but not the other ones you mentioned but I do hear another one at 7,061.76 as an example. ?My QCX-mini has the TCXO option and AGC option installed. ?I can barely hear the 7,143.65 when connected to an antenna but it’s very easy to hear when using a dummy load. ?Parameter settings may even impact what frequencies you hear spurious emissions as I have noticed that some disappear on my 20 meter QCX-mini when I hit the Keyer/RIT/Menu push button and the units displaying Speed only to reappear when I stop displaying speed. ?Also possible that things may be different if you have the TCXO option or not.

Don wd8dsb?

I have 2 that I built into GPS synch'd clocks with the QRP-Labs clock kit. I have another that is connected to my Win10 computer with a serial TTL to USB cable.



With a cable like this the GPS will appear as a computer serial port. I use the data from a "bare" GPS (no clock or additional display) to feed the program NMEATime2 to automatically set my computer time. Great for operating FT8, WSPR etc!

And today I ordered another GPS (This time the current QLG2) that I will use to automatically calibrate my QRPLabs SigGen kit!

--
73, Rick
VE7TK

Website:

On Tue, Jan 24, 2023 at 10:53 PM, Keith "Al" AG5GW wrote:

I bought a finished QLG1 GPS at a Hamfest last weekend. ?It seemed like a good deal at the time and I bought it in part because it had the magic QRP LABS name on it. ?But, at this point I really don't know what to do with it. ?Do I need the WSPR kit? or will this connect to other things? ?Any suggestions will be most appreciated. ?

Al. It gives 2 outputs: a one pulse per second signal (very accurate!) and a serial data stream which contains time, date and navigation info such as location.? It's used with various other equipment, for example to calibrate the timing for a QCX running WSPR.
?
--
Peter Lee
G3SPL

I bought a finished QLG1 GPS at a Hamfest last weekend. ?It seemed like a good deal at the time and I bought it in part because it had the magic QRP LABS name on it. ?But, at this point I really don't know what to do with it. ?Do I need the WSPR kit? or will this connect to other things? ?Any suggestions will be most appreciated. ?

Hi Hans

It is the original QCX Case I am looking for, not the boards. I have 6 classics built in plastic Chinese cases for desk use and they function perfectly in the shack. I was wanting to do some portable work this spring and thought I might transfer one of them into a original case. ( Bamatech have stopped producing them of course) if you have any cases left, doesn't matter what state they are in cosmetically, then I would be interested.

Gerry G4OJF?

--
gerry

Actually, NO, this probably needs to be an 'external' group-project with boards/semi-parts kits (JBLC, FAR Circuits) - stay tuned!

Hi Bob,

I think you have a good understanding of the limitations of working above 112.5 mhz where you need to use a fixed output divider of 4,6, or 8.? Finding the correct denominator is what Hans mentioned, rational best approximation.

What I have done with one of my WSPR projects is divide the XTAL frequency by my output divider and then divide again by my desired step, in my case 1.4648 and use that number for my value for c? in the a + b/c equation.? What this does is make each increment of b? in the equation result in the output frequency changing by the desired step, and then I have manipulated b directly to send the WSPR signals.?

In your case if you divide 25mhz by 6 and then by 6.66666667 you get the somewhat magic value (rounded) of 625000.
0.6080016 * 625000 is 380001 exactly.? The downside of this method is that setting your base frequency will have error, but the steps up from that frequency will be accurate.? ( must be careful using this approach? as c needs to be below 1048575, but works for 6.6667 steps on 144mhz ).

I took a look at the Adafruit library and it is an interesting way to approach things.? It does use float calculations for the divisions so I think it will have some error.

My WSPR code using this method is here:
The Si5351 routines would need changes to work on 144mhz with the fixed divider of 6.? This project also used an R divider for the transmit which would need to be removed.

Hi Paul,
I just looked at your website and learned about the NB3N502.? Because of the concern about spectral purity that Hans mentioned, I'm thinking of using this chip.? I'd divide the 15 MHz by 2 and configure this chip to multiply by 3.333.? An alternative is to use the Cypress CY22800 or CY22801 to convert the 15 MHz to 25 or 27 MHz.? The advantage of the latter is that I have these and their programmer on hand.? But the NB3N502 has a better jitter spec.? Do you think jitter even matters when feeding an Si5351A?
Halden VE7UTS

For anyone else who has fun hacking and changing things up, I have a QDX and 50w amplifier setup with auto-switched LPFs up for sale.? It could use a nice metal box to hold everything but I didn't get to that point.? It's listed on the QRZ swapmeet if you are a member there.? Here's some text from my ad:

Included is:
Revision 4 QDX transceiver 80m, 60m, 40m, 30m, 20m
50W Class D amplifier with metal case
Switchable LPF board (auto-switching with QDX)
Transistor buffer between QDX and LPF board with onboard 5v regulator for relay power
10m, 20m, and 40m LPFs built and installed.
80m and another LPF of your choice unbuilt.
DROK boost converter (needed for 50w amplifier)
All interconnecting cables

Just provide your own 12v, antenna, and computer and this is ready to use on 20m and 40m at 50w or other available bands at 5w.

I had this setup as a packet radio station for a while but decided to move back to 100w for HF packet as it provides better connections. I ran a little JS8 at 25w from time to time just for kicks.

You can sent me a private message or email (my QRZ email is correct) if you would like more information.? If you buy this setup, I can then buy more of Hans' kits and keep the cycle going.? I'm looking for $250 shipped which is equal to the cost of all the hardware involved.? I can have a QSO with you on-air with the setup if you are really interested.

73 DE Joshua, KJ7LVZ

Great, I am glad you got that sorted.? You are more likely to have a long-lasting QDX at this point.