Date   
Re: My QCX40 .....

Hans Summers
 

Hi Curt

The 40m QCX is well capable of almost 5W at 12V supply and 6W at 13.8V. Steve's figures aren't far off what I measure. 

20m, requires a bit more help (higher supply voltage). 

73 Hans G0UPL

On Fri, Jul 26, 2019 at 2:25 PM wb8yyy via Groups.Io <wb8yyy=yahoo.com@groups.io> wrote:
Steve

Instead say this rig is way cool, and that cw is cool music. Grab what you remember and let rest drop to the floor.

Minor, but not likely you are getting 6w from a convetional 12 or 13.8 volt power supply. 3 watts is the norm, not a huge difference from 5w. Maybe I should keep you thinking this rig is the larger critter.  it rocks.

Curt

Re: My QCX40 .....

@CurtisM
 

Steve

Instead say this rig is way cool, and that cw is cool music. Grab what you remember and let rest drop to the floor.

Minor, but not likely you are getting 6w from a convetional 12 or 13.8 volt power supply. 3 watts is the norm, not a huge difference from 5w. Maybe I should keep you thinking this rig is the larger critter.  it rocks.

Curt

Re: My QCX40 .....

Hans Summers
 

Hi Steve

Many congratulations OM!

I have a lot of fun on mine in the odd spare hour early morning at the crack of dawn, or late night... when there is quiet and a stolen peaceful hour. 

Since Monday, I have been on 40m CW and worked New Zealand, US, Japan, Qatar, Israel, and ~20 countries all around Europe from Northern Finland to Cyprus and loads in between. Admittedly, not QRP... QCX-40 driving my junkbox 60W amp (2x IRF510 push-pull, run at 24V). VK, still elusive...

Have fun! 

73 Hans G0UPL

On Fri, Jul 26, 2019 at 2:12 PM Stephen Farthing G0XAR JO92ON97 <squirrox@...> wrote:
Dear all, 

Just to say my QCX40 is complete. I’ve measured an output power of a gnats nadger below 6 watts. The receiver seems plenty sensitive and selective. Now all I have to do is remember the code and get the nerve up to use the damned thing. 

I’ve another QCX 40 to make to try out my pal Guido’s SSB conversion and a QCX 20 still in the bag. 

Greetings from a thundery but cooler South Norfolk 

Steve G0XAR 

My QCX40 .....

Stephen Farthing G0XAR JO92ON97
 

Dear all, 

Just to say my QCX40 is complete. I’ve measured an output power of a gnats nadger below 6 watts. The receiver seems plenty sensitive and selective. Now all I have to do is remember the code and get the nerve up to use the damned thing. 

I’ve another QCX 40 to make to try out my pal Guido’s SSB conversion and a QCX 20 still in the bag. 

Greetings from a thundery but cooler South Norfolk 

Steve G0XAR 

Re: qcx calibration

terryhugheskirkcudbrifght@...
 

hi thanks alan
i am still pondering the qcx

ok on the clock - the manual says it will stay stable for a week (maybe the u3s manual)_ so to check it daily seems ok

on the frequency - do you mean the wsjx display - i do not have an accurate frequency meter..

i have been reading both the qcx and u3s manuals but i am leaning towards the qcx cos its appears a bit less complicated than the u3s.  ie the u3s needs 5 v which would need a regulator to use my 12 v battery, to equal the pa out it needs the 5 w pa. the advantage of the u3s is that it can multi band and also multi mode.

but both need the same calibration

you may be interested that my exiting station has two transceivers - a vintage trio ts520se and a ubitx. neither can be said to be accurately calibrated. my antenna are dipoles for 40 and 20 and a g5rv with atu mainly for use with 80 m.

my test equipment is fairly limited ie a scope, dummy load, a frequeny counter but only four sig decimal digits, a dvm,

i am currently looking for a project to keep my soldering iron busy and wspr may be the answer.

terry gm4dso




Re: #u3s Relocating R5 #u3s

Hans Summers
 

Hi Nik...

I don't have a particular opinion on it... unless I tried it out myself... but that would involve having an RD-whatsit. And having some time :-//    If you do try it out, then let me know how it goes!

73 Hans G0UPL

On Thu, Jul 25, 2019 at 9:20 PM <nik@...> wrote:
What do you reckon to replacing the BS170s with one. Is there enough level from the XO to drive it?  Obviously the connecting to the U3S would be a faff. 

Re: QCX R36 Replacement Needed-Volume Control

Ted 2E0THH
 

Hi Brian

I think you will find the 5k pot supplied is linear (even though the schematic says log).
Ideally log, but the difference is not that alarming.
5k logs are actually quite hard to find and expensive (UK)

73s Ted
2E0THH

Re: 5 Watt PA

M0RON
 

Hi Vernon,
as you are building the amp simple style, have you installed the wire links as per the manual?
73
Andy
--
The universe is made up of Protons, Neutrons, Electrons but contains only one M0RON.

Re: 5 Watt PA

KEN G4APB
 

 with the 4.7k trimmer completely off and then slowly bring it up during TX but I get nothing.
with no rf input you should see the dc current input rise as you increase the pot. if this is not happening start checking dc volts around the PA device.

73 Ken g4apb 

Re: qcx calibration

Alan G4ZFQ
 

do not really want the gps receiver
can i calibrate the qcx by a ) setting the time dailey
                                         b )  looking at my own signals on wsjx and setting the frequency
to be on the waterfall
Terry,

Look at the manual. Section 8.6 for example tells you how to set the clock reference so it stays on time for a good while.
Similarly the frequency reference may be set so the display is accurate.

73 Alan G4ZFQ

Re: QCX: Calculation of low pass filter for PA?

Alan G4ZFQ
 

is there a design tool in RFSIM99 with which this can be done?
Axel,

A search found "There are even built in calculators in the Tools menu which can automatically design and simulate filters for you."

Now to look at the program...

73 Alan G4ZFQ

Re: QCX: Calculation of low pass filter for PA?

Axel
 

Karlis, I did many trials with https://home.sandiego.edu/~ekim/e194rfs01/jwmatcher/matcher2.html , but I cannot get to the values of the NB6M miniboots PA. I think, you tried it, too.

RFSIM99: I have placed the parts into RFSIM99 and did successfully run the simulation. Now, how can I get the right parts' values? Just by manually setting different values and see what the simulation gives? Or, is there a design tool in RFSIM99 with which this can be done?

Axel, DF1ET

Re: QCX R36 Replacement Needed-Volume Control

Brian N7BKV
 

Yes, I used cleaner.  No joy.

Re: 5 Watt PA

Ham Radio
 

Try measuring the DC  current draw on the one that works versus the one that does not work.  That test will tell you quite a bit.

An o-scope will tell you the true story on what is going on ...
--
73, Bernie, VE3FWF

Re: 5 Watt PA

Vernon Matheson
 

I just got one going. I touched up all the pads with the iron and I think I had a cold joint where the 10 ohm resistor connects to the IRF510 pad on that mod. It started working.

 

The other one is beyond hope as it was the very first one I built and I have added and removed so much stuff on it that I screwed a couple of pads trying to install another toroid tonight.

 

Will scavenge the parts and buy another.

 

Cheers

 

Vernon

 

Re: QCX R36 Replacement Needed-Volume Control

Ham Radio
 

Did you try contact cleaner on the pot?  That pot should last for years ...

--
73, Bernie, VE3FWF

Re: qcx calibration

N3MNT
 

I am reading into your questions that you are interested in doing WSPR. You can set the clock manually and it will be work OK for a while, but you will need to reset it the next time you use it.  As for the freq that can be set without the GPS.  At the low cost of the GPS and the hour or so to build it, I would add the GPS module simply for convenience.  Download the build/setup instructions for more details on WSPR and freq calibration.

qcx calibration

terryhugheskirkcudbrifght@...
 

i am thinking of buying a qcx but i do not really want the gps receiver

can i calibrate the qcx by a ) setting the time dailey

                                         b )  looking at my own signals on wsjx and setting the frequency    
to be on the waterfall

terry gm4dso

Re: 5 Watt PA

m0bmn
 

Hi Vernon

I was just  thinking, I know you have checked and double checked but could you have possibly mixed the windings on the output transformer, it could still bell out but be wired wrong. Like you say there is not a lot to go wrong. I have built a couple of my own IRF510 amps , slightly different output transformer but I had to put a small inductor in series with the resistor from the trimer to stop the RF from taking the easy path to ground. I’m sure Hans’s amp , on its nice PCB doesn’t have this problem, I bet there are near a 1000 out there working like champs.

They should work well, I find it can copy with full time key down with a suitable heatsink and even with a small (ish) heatsink and a cheap 40x40mm fan it seems to run cool. Hope you get them sorted.

Its going to be something daft I bet.

73 Paul

 

Sent from Mail for Windows 10

 

From: Vernon Matheson
Sent: 25 July 2019 20:55
To: QRPLabs@groups.io
Subject: FW: [QRPLabs] 5 Watt PA

 

Resend with correction

 

I have 3 of the 5 watt PA units and are of simple build. For the life of me I can only get one to work.

There are 5 #105 capacitors, one 3.3k resistor, one  78L05 100ma voltage regulator, a FT50-43 trifilar toroid, a 4.7k trimmer potentiometer resistor, and a IRF510 and the 10 ohm resistor used in the mod on the bottom side of the board plus 4 jumpers that are in the correct position.

I am running it at 13.8 volts and that is what is shown at the board input pads.

I have changed the IRF510's,  78L05 regulators, and 4.7k trimmer potentiometer resistors on both the ones that do not work..

I am feeding them with the same U3S that feeds the one that does work. All 3 have similar RF in and out connections.

The FT50-43's check out with the meter as shown in the manual.

Looking for any insight as what could be wrong. There is hardly anything on the board to go wrong with.LOL!!!

I was going to change out the rest of the parts that hadn't been already changed but thought I would check here first.

I set the U3S  and working amp for say 3 watts on 40M. I replace the working amp with one of the others with the 4.7k trimmer completely off and then slowly bring it up during TX but I get nothing.


Vernon - VE1VDM

 


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Re: Pico Balloon Launch LightAPRS N6CVO-11

BrianB
 

Flight Day 6 (maybe)

25-JUL-2019 21:30:00 UTC

Contact with the balloon was expected today but nothing was received :-(

This is not looking good for the flight but don't loose hope yet. FL300(30,000') winds off the European coast have not been friendly for our flight and there are three different things could have happened:

1) The balloon went down due to wind sheer or just fatigue from its days in the air.

2) It stayed in the Jetstream and swung north over Ireland where airborne Amateur Radio transmissions are forbidden and the GeoFencing software shut the transmitter down until it clears the area. From there it would head further North then either turn Northwest towards Iceland or it will turn East towards Norway where there are ground stations to pick up the transmissions.

3) It dropped out of the Jetstream as it was approaching the European coast. This would trap it in a low pressure zone and send it west again for another lap around the Atlantic where there are no ground stations.

Looking at the wind charts I think it went over Ireland then north, but whether it turns West or East after that is anyone's guess. Lets just hope it's still floating around up there.

We will keep looking for a few more days before declaring end of flight.

73,
BrianB
N6CVO