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Re: Argh QMX Q103/Q104 short

 

My QMX kit arrived with the short in place. ?

I removed Q104 (the little one) and the pad was still shorted to Q103’s tab. ?

Using just a soldering iron I first lifted Q103’s two leads. ?Then I heated the tab until I could pull off the part with tweezers. ?

At that point the pads were no longer shorted. ?

I reinstalled the devices at the edges of their pads to increase their spacing. ?All is well. ?

I had no problem with the procedure using just a couple of Metcal soldering tips, one small and the larger one for the tab. ?

Disclosure: ?I did this work using a 7 power stereoscope. ??

Jerry
N6JH
Re: QDX - protection of BS17O PA

 

Note that for the QMX (not the QDX) There are unpopulated holes for potential use of these? diodes at D503 and D504. The jury is out on whether these are needed pending additional testing.

-Steve K1RF


------ Original Message ------
Date 9/1/2023 10:23:44 AM
Subject Re: [QRPLabs] QDX - protection of BS17O PA

After smoking finals in 3 different bad swr occasions ?that’s what I do to protect my qdx finals and it works. Many use in the field with bad swr and even no antenna connected by error.?

73

Barb WB2CBA
Re: FT8 for U3?

 

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OK, but how is FT8 a beacon mode? ?Just call CQ and never answer, and then scrape spots off pskreporter or some such? ?Or are you listening for FT8 and doing some kind of reverse beacon thing?

I guess I’m not seeing it. ?Why not use SSB for your beaconing? ?8*)

73, Willie N1JBJ

On Sep 1, 2023, at 10:39 AM, Nigel ZS6RN <zs6rn@...> wrote:

<IMG_3805.jpeg>Hi Willie,

Thanks for prompt response!

I will try to expand current scenario, are you sitting comfortably? <grin>


Short version:
During the monthly beacon team meeting last night mention was made of a paper being presented at the upcoming IARU Region 1 conference (screen shot of title page attached) which discusses using FT8 and that our project team should revisit the modes we intend using.

As an aside, one of our VHF beacons is being used for meteor scatter research by several hams and the plan is to try and optimise the mode(s) being used to help support their efforts.

Am looking forward to further feedback on this forum for sure!

73

Nigel ZS6RN ex G8DEV
Re: ChatGpt/GPT4

 

Andy it's exactly what they are guaranteeing they won't do, but that is off topic so won't expand further.
Re: ChatGpt/GPT4

 

I uploaded photos of my soldered QMX boards and asked it to check for problems, solder bridges, out gave me a whole raft of tips where to look regarding Rx problems, so yes it's very much on topic with qrp-labs.
Re: GPS disciplined oscillator.

 

Thanks for you ticket reply to my question, Hans. I've ordered one of each Progrock2 and QLG2. It would certainly be considerably cheaper than the alternatives! They will be boxed with a stable psu and I will see if buffering and filtering are required. Would be a great solution for Pluto based QO100 transceivers where even with a new, high stab tcxo, on tx it still drifts.

Regards,

Roger (G8VLR).
Re: ChatGpt/GPT4

 

Yes Bob but before 2021, where exactly it was trained is a bit of a secret, but for sure the internet as well.

Paul DJ0CU G4ADF?
Re: FT8 for U3?

 

Hi Nigel

It IS on my ToDo list for U3S... but, I'm sure you can imagine, my ToDo list is not very short.?

73 Hans G0UPL



On Fri, Sep 1, 2023 at 5:39?PM Nigel ZS6RN <zs6rn@...> wrote:

Hi Willie,

Thanks for prompt response!

I will try to expand current scenario, are you sitting comfortably? <grin>


Short version:
During the monthly beacon team meeting last night mention was made of a paper being presented at the upcoming IARU Region 1 conference (screen shot of title page attached) which discusses using FT8 and that our project team should revisit the modes we intend using.

As an aside, one of our VHF beacons is being used for meteor scatter research by several hams and the plan is to try and optimise the mode(s) being used to help support their efforts.

Am looking forward to further feedback on this forum for sure!

73

Nigel ZS6RN ex G8DEV
Re: SSB instead of CW in the logbook

 

My impression is that is due to the QMX reporting a 3200 Hz receiver bandwidth, i.e. the digi bandwidth, instead of the actual CW bandwidth.
Gary
W9TD
Re: FT8 for U3?

 

Hi Willie,

Thanks for prompt response!

I will try to expand current scenario, are you sitting comfortably? <grin>


Short version:
During the monthly beacon team meeting last night mention was made of a paper being presented at the upcoming IARU Region 1 conference (screen shot of title page attached) which discusses using FT8 and that our project team should revisit the modes we intend using.

As an aside, one of our VHF beacons is being used for meteor scatter research by several hams and the plan is to try and optimise the mode(s) being used to help support their efforts.

Am looking forward to further feedback on this forum for sure!

73

Nigel ZS6RN ex G8DEV
Re: QDX - protection of BS17O PA

 

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IMHO, this method is valid also but requires two diodes. Why not eliminate the spike at the source??

If you have two QDX, you might try using the L14 diode in one of them and see if it gives you any issues.

Tony
AD0VC

From: [email protected] <[email protected]> on behalf of wb2cba@... <wb2cba@...>
Sent: Friday, September 1, 2023 8:23 AM
To: [email protected] <[email protected]>
Subject: Re: [QRPLabs] QDX - protection of BS17O PA
?
After smoking finals in 3 different bad swr occasions ?that’s what I do to protect my qdx finals and it works. Many use in the field with bad swr and even no antenna connected by error.?

73

Barb WB2CBA
Re: Dire need of a part

 

Dave,
I checked our stock at work and we use aTDK part: GLFR1608T470M-LR.? ?Described as a 47UH? 0603 power inductor 20%.
From the schematic, it looks like they are power not RF.? Let me see if I can get them.? ?

Let me now if it sounds like what you?are looking for?

Bob
WA1EDJ
LF,IND,PWR,0603,47UH,100MA,20%
GLFR1608T470M-LR
GLFR1608T470M-LR


On Thu, Aug 31, 2023 at 11:22?PM David R. Hassall WA5DJJ <dhassall@...> wrote:

Dear Karl,
I went to the QDX v5 manual and the size of most of the parts in the QDX are 603.?? There is no size given for the 47uh inductors.? All it gives is the inductance value and SMD.

so, I really don't know what the size is.?? maybe you can get an idea from the picture.?? I wish I still had the two hanger queens of broken ones that some of the guys here brought

for me to fix.?? Then the job would have been easy.?? I would have taken one of the 5 47uh SMD inductors out and put it in place of my broken one.

Take care and have fun.
73 Dave WA5DJJ

"anything worth doing isn't always EASY!"
Re: QDX - protection of BS17O PA

 

After smoking finals in 3 different bad swr occasions ?that’s what I do to protect my qdx finals and it works. Many use in the field with bad swr and even no antenna connected by error.?

73

Barb WB2CBA
Re: QDX - protection of BS17O PA

 

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For the QDX, install the 1N4148 in parallel with L14 with the banded end of the diode connected to +12V end of L14.

I personally would like to hear from anyone who has fried a BS170 with this diode installed.

Tony
AD0VC

From: [email protected] <[email protected]> on behalf of SeaBass <kodiakat777@...>
Sent: Friday, September 1, 2023 2:12 AM
To: [email protected] <[email protected]>
Subject: Re: [QRPLabs] QDX - protection of BS17O PA
?
With all due respect - Homes have circuit breakers, smoke detectors, and fire extinguishers for a reason......

It's not that we are purposely risky with electrical and/or fire hazards, but we recognize that components and systems can and do fail, despite operating within safe standards.

I would like more information on the diode solution to protect the BS150s, including the correct polarity for insertion of the diode into the circuit.? I already have ancillary low-profile copper heat sinks installed on my four QCX-Minis, all of which are running a 24/7 WSPR Duty cycle, I am hoping the diodes will help further extend the lifecycle of the heavily used components.? ?I have two dozen spare BS150s in bench stock, however, I've already ruined the thin copper PCB traces on both a QSX-Mini and U3S board by replacing BS150 components; I'm hoping to avoid or minimize replacements in the future.??

I do recognize the good advice to be cognizant of SWR and not push source voltage to the extreme, a common self-inflicted failure factor with these micro devices, but if adding a 10-cent diode will extend the MTBF I'm on board to give it a try.

Thanks?

Brian, AA5H / 3W90K?

Re: FT8 for U3?

 

Why wouldn’t you use WSPR? That’s much more applicable to beacon use than FT8, which requires an operator…

73, Willie N1JBJ

On Sep 1, 2023, at 9:49 AM, Nigel ZS6RN <zs6rn@...> wrote:

Greeting all?

I am involved with a VHF beacon project and for some time the team had settled on using PI4 plus CW as the Tx modes. We are now contemplating if FT8 would / could yield more reports / feedback being as FT8 is very popular.

As part of a pilot was thinking to configure a U3 to Tx both PI4 and FT8 plus CW but seems inclusion of FT8 has not yet been released.

Anyone care to comment / make suggestion(s) regarding U3S FT8 and or merits of FT8 vs PI4 (or any other modes)? Aim of project is as a tool to explore VHF propagation throughout South Africa.

There is possibility of using a RFZero as this unit supports FT8 but would be more acceptable to use the U3S that was built for this project.

Advance thanks for any and all feedback.

73

Nigel ZS6RN ex G8DEV
Re: QMX AM/USB/LSB

 

Thanks Hans!? Exciting!
Re: QMX Shipped, panic stage #qmx

 

Karl, you sent this to the WRONG topic and guy. NOT ME! Checking all messages sent on groups.io, I found the original message as below. Not upset, trying to help both of you.

So sorry, I hit the wrong thing on screen (again!)!
?
--
73
Karl
KI4ZUQ
Re: FT8 for U3?

 

Greeting all?

I am involved with a VHF beacon project and for some time the team had settled on using PI4 plus CW as the Tx modes. We are now contemplating if FT8 would / could yield more reports / feedback being as FT8 is very popular.

As part of a pilot was thinking to configure a U3 to Tx both PI4 and FT8 plus CW but seems inclusion of FT8 has not yet been released.

Anyone care to comment / make suggestion(s) regarding U3S FT8 and or merits of FT8 vs PI4 (or any other modes)? ?Aim of project is as a tool to explore VHF propagation throughout South Africa.

There is possibility of using a RFZero as this unit supports FT8 but would be more acceptable to use the U3S that was built for this project.

Advance thanks for any and all feedback.

73

Nigel ZS6RN ex G8DEV
Re: GPS disciplined oscillator.

 

Hello Alan

There should not be any 0.5 Hz frequency modulation. If ProgRock2 is set up correctly and on a stable supply in a stable environment, within a few minutes of power up, it should achieve step sizes of 0.027 parts per billion.?

Put another way, if you have it set to 10MHz output, the frequency modulation will be?+/- 0.137 milli Hertz.?

73 Hans G0UPL



On Fri, Sep 1, 2023 at 4:36?PM Alan G4ZFQ <alan4alan@...> wrote:
> I'm wondering if I can use the Progrock2 with the QLG2 to form a GPS
> disciplined oscillator that I can use with my Adalm Pluto requiring
> 40MHz local oscillator?

Roger,

My tests indicated that the PPS modulates the output.
Just a little +/- 0.5Hz, but I'd be wary to use it for a reference.
I have just left it, no further checks, there have been a few other
reports that have not mentioned that, maybe not noticed or not present?
Or, just bad connections?

73 Alan G4ZFQ
Re: GPS disciplined oscillator.

 

I'm wondering if I can use the Progrock2 with the QLG2 to form a GPS disciplined oscillator that I can use with my Adalm Pluto requiring 40MHz local oscillator?
Roger,

My tests indicated that the PPS modulates the output.
Just a little +/- 0.5Hz, but I'd be wary to use it for a reference.
I have just left it, no further checks, there have been a few other reports that have not mentioned that, maybe not noticed or not present? Or, just bad connections?

73 Alan G4ZFQ
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