Date   
Re: Question regarding measuring power output.

Steve in Okinawa
 

For the record I was replying to the surprising idea of measuring input power as a way to know how well the QCX is working. As an old timer like me you probably also used to tune up novice rigs with a 100 watt bulb and single clip lead, but on this forum there is s great gnashing of teeth over 2.8 watts instead of 3.2, followed by surgery to the new build. Believe me, I am not the slightest bit concerned with that, but since many here are technically advanced, I just wanted to insert something about true RMS measurement. 

Re: Upgraded Firmware to 1.04

Gregg Myers
 

I should phrase it correctly like you did, the IF-Q balance and Phase Low and Phase High. That is really the correct wording. Not the BPF and LPF. But those don’t change with firmware.

On Fri, Apr 3, 2020 at 11:14 PM Gregg Myers via groups.io <gregg.w7grm=gmail.com@groups.io> wrote:
Hi Al,

Upgrading the firmware does not change the potentiometer settings (e.g. the BPF  and the LPF alignment). However it could reset the oscillator cal frequency.  This is the 27 MHz cal frequency in menu 8.11, if I’m not mistaken. If you are off frequency, you only need to tweak that ref oscillator value. The correct value is usually slightly higher than 27.000.

Good luck & Enjoy
Gregg
W7grm

On Fri, Apr 3, 2020 at 11:04 PM Allen Lee <alee@...> wrote:
Did the upgrade to firmware. Now wondering if I need to go through the alignment steps again? Seems to be a bit off frequency or Im not reading
it right. Got good low setting on the IF-Q Balance and Phase Lo and Phase Hi. Also had nice high reading on the Peak BPF settings. Had a few bugs
at first but that was my soldering issue not the kit.

Also had fun with the toroids! Dont think Ill do that again. Big fingers and shaking hands didnt help much but got them wound and working. Soldering
then in place was a different matter but struggled through that. Satisfaction was that it worked when I got done. First QSO was on my 40 M ground mounted
vertical with a station in Columbus, GA. with RST of 599.

Thanks
Al WB7SWW

Re: Upgraded Firmware to 1.04

Gregg Myers
 

Hi Al,

Upgrading the firmware does not change the potentiometer settings (e.g. the BPF  and the LPF alignment). However it could reset the oscillator cal frequency.  This is the 27 MHz cal frequency in menu 8.11, if I’m not mistaken. If you are off frequency, you only need to tweak that ref oscillator value. The correct value is usually slightly higher than 27.000.

Good luck & Enjoy
Gregg
W7grm


On Fri, Apr 3, 2020 at 11:04 PM Allen Lee <alee@...> wrote:
Did the upgrade to firmware. Now wondering if I need to go through the alignment steps again? Seems to be a bit off frequency or Im not reading
it right. Got good low setting on the IF-Q Balance and Phase Lo and Phase Hi. Also had nice high reading on the Peak BPF settings. Had a few bugs
at first but that was my soldering issue not the kit.

Also had fun with the toroids! Dont think Ill do that again. Big fingers and shaking hands didnt help much but got them wound and working. Soldering
then in place was a different matter but struggled through that. Satisfaction was that it worked when I got done. First QSO was on my 40 M ground mounted
vertical with a station in Columbus, GA. with RST of 599.

Thanks
Al WB7SWW

Upgraded Firmware to 1.04

Allen Lee
 

Did the upgrade to firmware. Now wondering if I need to go through the alignment steps again? Seems to be a bit off frequency or Im not reading
it right. Got good low setting on the IF-Q Balance and Phase Lo and Phase Hi. Also had nice high reading on the Peak BPF settings. Had a few bugs
at first but that was my soldering issue not the kit.

Also had fun with the toroids! Dont think Ill do that again. Big fingers and shaking hands didnt help much but got them wound and working. Soldering
then in place was a different matter but struggled through that. Satisfaction was that it worked when I got done. First QSO was on my 40 M ground mounted
vertical with a station in Columbus, GA. with RST of 599.

Thanks
Al WB7SWW

Re: QCX interchangeability of toroids

Shirley Dulcey KE1L
 

When you buy a QCX you get two packages. One has most of the parts for the QCX, including most of the parts that you need to build it for any band. The other has the low pass filter components. Those are identical to the low pass filter kit that Hans sells, except that no PCB is included because the parts go on the QCX board.

Low pass filters for 80 and 60 meters contain T37-2 red toroids. LPFs for 40 through 4 meters contain T37-6 yellow toroids. The toriods for an 80m QCX LPF will also work on 60m and vice versa; similarly, the toroids for the kits from 40 through 17 meters are interchangeable. The kit for a different band will not contain the same capacitor values so you will have to come up with replacements for those.

Although each toroid mix has an optimum frequency range, those ranges overlap. You could build a low pass filter for 80 or 60 meters using the yellow toroids, or filters for 40 meters and higher frequencies using the red toroids, and they would work just fine. But you would have to calculate new numbers of turns, and possibly new capacitor values to go with them. If you used the yellow toroids on 80 or 60 meters the necessary number of turns for the inductors might not fit, requiring you to wind them with overlapping turns; the inductors would still work.

Low pass filter kits for 2200m through 160m contain T50-2 red toroids. Those are bigger cores that make it possible to put on the large numbers of turns that are needed for those bands. The QCX is not available for those bands, so you don't have to worry about squeezing the bigger toroids.


On Fri, Apr 3, 2020 at 11:11 PM Phil Frost <indigo@...> wrote:
The iron core materials are color coded. If the cores are the same color and size, they are probably interchangeable. 

If they aren't the same color, you still might be able to make something that works. Check out https://toroids.info/ and see if there's a way to make the right inductance and/or check the inductance with whatever test equipment you have. Sometimes using a different core material results in higher loss, and sometimes that's important. But often performance is good enough with a different material. 

On Fri, Apr 3, 2020, 19:54 Mike Easterbrook <mike.easterbrook.2012@...> wrote:
Hi All
Due to a problem with my keyboard skills (I'm sure it isn't  a sinister marketing ploy ..... joke!) - both times I have ordered a QCX kit I have received two.  No problem - I thoroughly enjoy the construction & troubleshooting challenges, which are good therapy for my age related declining skills (try changing IC1 with shaky hands!) also welcome activity during "stay home" restrictions.

So I have 2 x 30m and 2 x 40m kits.  Question is can I re-purpose the spare kits to other bands by simply winding the coils with the appropriate number of turns or are the toroids themselves only suitable for the original bands?

Sorry if this is a stupid or duplicate question - my searching skills aren't too hot either!

Thanks Mike 9M2LXM/9V1lX

Re: QCX interchangeability of toroids

Phil Frost
 

The iron core materials are color coded. If the cores are the same color and size, they are probably interchangeable. 

If they aren't the same color, you still might be able to make something that works. Check out https://toroids.info/ and see if there's a way to make the right inductance and/or check the inductance with whatever test equipment you have. Sometimes using a different core material results in higher loss, and sometimes that's important. But often performance is good enough with a different material. 


On Fri, Apr 3, 2020, 19:54 Mike Easterbrook <mike.easterbrook.2012@...> wrote:
Hi All
Due to a problem with my keyboard skills (I'm sure it isn't  a sinister marketing ploy ..... joke!) - both times I have ordered a QCX kit I have received two.  No problem - I thoroughly enjoy the construction & troubleshooting challenges, which are good therapy for my age related declining skills (try changing IC1 with shaky hands!) also welcome activity during "stay home" restrictions.

So I have 2 x 30m and 2 x 40m kits.  Question is can I re-purpose the spare kits to other bands by simply winding the coils with the appropriate number of turns or are the toroids themselves only suitable for the original bands?

Sorry if this is a stupid or duplicate question - my searching skills aren't too hot either!

Thanks Mike 9M2LXM/9V1lX

Re: QCX interchangeability of toroids

Paul AI4EE
 

Download the 80 & 20 manuals and find the differences between them and the 40 & 30 manuals. Unless you want some other band(s), of course.


On 4/3/2020 10:53 PM, Mike Easterbrook wrote:
Hi All
Due to a problem with my keyboard skills (I'm sure it isn't  a sinister marketing ploy ..... joke!) - both times I have ordered a QCX kit I have received two.  No problem - I thoroughly enjoy the construction & troubleshooting challenges, which are good therapy for my age related declining skills (try changing IC1 with shaky hands!) also welcome activity during "stay home" restrictions.

So I have 2 x 30m and 2 x 40m kits.  Question is can I re-purpose the spare kits to other bands by simply winding the coils with the appropriate number of turns or are the toroids themselves only suitable for the original bands?

Sorry if this is a stupid or duplicate question - my searching skills aren't too hot either!

Thanks Mike 9M2LXM/9V1lX

Re: Question regarding measuring power output.

Paul AI4EE
 

Bravo, Jim!


On 4/3/2020 9:01 PM, Jim Allyn - N7JA wrote:
I don't think any of us here really need to know the power output of their QCX with accuracy traceable to NIST (or whatever the standards organisation is in your country).  I think what most of us want to know is: is it working?  Is it putting out as much power as it's supposed to?  There are many ways to measure power to the sort of accuracy needed for that.  The original poster's method of observing the waveform on an oscilloscope connected to his dummy load is fine, he just didn't have the right formula to calculate the power properly.  Now he does.  Peak detecting the RF power with a diode and a capacitor and measuring the DC voltage with a voltmeter or a scope is also fine.  You could probably measure the temperature rise in the dummy load, if all you had was a thermometer.  Or put a 50 ohm resistor rated at 2 or 3 watts on the output of the transmitter and see if any smoke rises. If not, repeat the procedure with lower wattage resistors until it does.  Or run the transmitter into an appropriate incandescent light bulb and see how bright it glows.  I think we're all hams here, right?  And hams are resourceful, right?

QCX interchangeability of toroids

Mike Easterbrook
 

Hi All
Due to a problem with my keyboard skills (I'm sure it isn't  a sinister marketing ploy ..... joke!) - both times I have ordered a QCX kit I have received two.  No problem - I thoroughly enjoy the construction & troubleshooting challenges, which are good therapy for my age related declining skills (try changing IC1 with shaky hands!) also welcome activity during "stay home" restrictions.

So I have 2 x 30m and 2 x 40m kits.  Question is can I re-purpose the spare kits to other bands by simply winding the coils with the appropriate number of turns or are the toroids themselves only suitable for the original bands?

Sorry if this is a stupid or duplicate question - my searching skills aren't too hot either!

Thanks Mike 9M2LXM/9V1lX

Re: Did I destroy my Receiver Module?

Bruce K1FFX
 

Just to close this off:

Actually, I didn't damage it at all (!).  Took me a couple of days to get some SDR software
up and running (gave up on Linux, so running HDSDR in Windows in a virtual machine),
hooked up the receiver module and LO and, amazingly, the receiver works fine.

- Bruce K1FFX

Re: Question regarding measuring power output.

Jim Allyn - N7JA
 

I don't think any of us here really need to know the power output of their QCX with accuracy traceable to NIST (or whatever the standards organisation is in your country).  I think what most of us want to know is: is it working?  Is it putting out as much power as it's supposed to?  There are many ways to measure power to the sort of accuracy needed for that.  The original poster's method of observing the waveform on an oscilloscope connected to his dummy load is fine, he just didn't have the right formula to calculate the power properly.  Now he does.  Peak detecting the RF power with a diode and a capacitor and measuring the DC voltage with a voltmeter or a scope is also fine.  You could probably measure the temperature rise in the dummy load, if all you had was a thermometer.  Or put a 50 ohm resistor rated at 2 or 3 watts on the output of the transmitter and see if any smoke rises. If not, repeat the procedure with lower wattage resistors until it does.  Or run the transmitter into an appropriate incandescent light bulb and see how bright it glows.  I think we're all hams here, right?  And hams are resourceful, right?

Re: Question regarding measuring power output.

Steve in Okinawa
 

I didn't want to be the first to say it, but that would be one of the most inaccurate ways to determine power output. Also, we're accustomed to dealing with pure(ish) sinusoids in RF measurements but if it is something other, the only authentic power measurement would use meters that measure true RMS by means of heating effects.

Re: Pre-wound Toroids

Arv Evans
 

Still curous about what you find so funny about introducing kids to ham radio.  

Arv. K 7HKL
_-_


On Fri, Apr 3, 2020, 1:46 PM Gary Bernard via groups.io <garybernard2=aol.com@groups.io> wrote:
LOL big time.


-----Original Message-----
From: Richard Lawn <rjlawn@...>
To: QRPLabs <QRPLabs@groups.io>
Sent: Fri, Apr 3, 2020 1:03 pm
Subject: Re: [QRPLabs] Pre-wound Toroids

Can you hear me laughing!

On Fri, Apr 3, 2020 at 2:25 PM Arv Evans <arvid.evans@...> wrote:
Winding toroids could be an execelent way to introduce kids to ham radio.

_-_


On Fri, Apr 3, 2020, 11:57 AM Richard Lawn <rjlawn@...> wrote:
Thanks guys. I’ve used him before with other kits. 

73
Rick, W2JAZ 

On Fri, Apr 3, 2020 at 1:29 PM Michael N6MST <mthompson.cob@...> wrote:
Mychael AA3WF does exactly this. He is the go-to guy for pre-wound toroids. He will wind to your specs for a fee and he does very good work. You can email him at toroidguy@...
--

Re: Pre-wound Toroids

Arv Evans
 

Wat did you find so funny.
_-_



On Fri, Apr 3, 2020, 1:03 PM Richard Lawn <rjlawn@...> wrote:
Can you hear me laughing!

On Fri, Apr 3, 2020 at 2:25 PM Arv Evans <arvid.evans@...> wrote:
Winding toroids could be an execelent way to introduce kids to ham radio.

_-_


On Fri, Apr 3, 2020, 11:57 AM Richard Lawn <rjlawn@...> wrote:
Thanks guys. I’ve used him before with other kits. 

73
Rick, W2JAZ 

On Fri, Apr 3, 2020 at 1:29 PM Michael N6MST <mthompson.cob@...> wrote:
Mychael AA3WF does exactly this. He is the go-to guy for pre-wound toroids. He will wind to your specs for a fee and he does very good work. You can email him at toroidguy@...

--

Re: QCX Assembly Question #qcx

fred.g3srf@...
 

Why do you need a calculator. It is easy to work out how much wire is needed to each turn and then multiply by the number of turns. You could also wind a piece of thin string in place of the wire, remove it and then measure it.

Re: QCX Assembly Question #qcx

fred.g3srf@...
 

All the assembly instructions for QRP Labs Kits are available online. You must have had time to download the instructions while waiting for your kit to arrive. You should have read the whole document before you even un-packed the kit. Hans spends a lot of time writing the instructions, you can't blame him for your errors.

Re: QCX Assembly Question #qcx

John Brock
 

I had to rework T2. Bought 28ga magnet wire on Amazon. You might decide re-working T1 is easier with new wire.

Also, be sure to scrape off the enamel coating before trying to solder to the PC board. I learned the hard way.

Could not burn off the enamel without first scraping some (most?) of the enamel off at the point I needed to solder.

I like the Knipex coated wire stripping tweezers tool for this. Found it easier than a knife and sandpaper. Also on Amazon or Home Depot (special order).

 

I also bough magnet wire when I assembled the 50W amp. Came in handy there too.

 

John

WA8US

Re: #20m QCX #20m

James Daldry W4JED
 

Hi, Steve

So far, so good on the keeping safe. The XYL and I walk about 3 miles each, morning and afternoon, but try to stay away from folks coming the other way.

Yep, looks like you're in the market for some ChipKwik. My 2 methods are:

(1) Wick off as much solder as possible. If the original is lead-free, drown it in 63/37, then wick it again. Then insert a small jewelers screwdriver between the legs and heat one leg.The solder on the leg pressed at the end will "pop" just before it melts. Once off, wick the pads again.

(2) Wick. Then insert a piece of wire from a bread tie between the legs and the body of the IC, Solder one end of the wire to a nearby blob. Then pull on the wire while sliding the solder pencil along the ends of the legs. It's a little tricky, but faster than the first method.

Back in my TV shop days we repaired both store stock equipment and customer equipment in warranty. Since you never knew when repair parts would come in, and customers expect fast turn around, if you had a stock unit in for repair it became an "organ donor" for the customer sets. The very first time I changed a surface mount IC it was a 64 pin servo IC (square, 16 pins on a side) for a Sanyo VCR. I had to remove the bad IC, pull one off a stock unit, use that IC to repair a customer unit, and put the new one in the stock one after it came in. If you read your equipment warranties you will find that the warranty repair station can use used or rebuilt parts for warranty. It's only after the unit is out of warranty that you can insist on new parts.

73

Jim W4JED

On 4/3/20 10:48 AM, steve Jones via groups.io wrote:
Hi James, 
                 thank you for replying to my query.

Well I decided that it would be good to confirm whether there was an issue with T1 secondary windings in respect of them being either O/C or H/R. So I removed each leg that feeds pins 7 and 9 of IC4, this revealed that the centre tap connected at the junction was 2.5V when power was applied.

T1 secondary is OK.

C1 is OK and not S/C, so I must assume that IC4 is at fault when connected to T1 secondary via pins 7 and 9 and that maybe the method by which it appears to have failed is the reason for it dragging down the 2.5V derived at the junction of R1 and R2, hence  this potential cannot propagate through to bias IC5 tending toward IC8.

On inspection the pins on IC4 look OK in terms of soldering and being free of any S/Cs.

Maybe the next stage is to perform surgery and remove the current IC4 with a new one - fortunately I have one in stock.

Thanks again, I hope you are keeping well and safe at this difficult time.

Steve

Re: QCX Assembly Question #qcx

alexwalters08@...
 

Thanks to everyone who replied,

I brought out the calipers and the multimeter and the wires are the same gauge and are both enamel coated.  Not sure what their difference is besides color.  I also did some digging around a found a picture online that showed the red wire packaged in the LPF bag with L1-3 and the copper-colored wire in the main bag with T1 and L4.  I am going to wind the toroids with the wire that was supplied in their respective bag as is said on page 11.  It is my fault for not noting which wire came in which bag when I laid out all the parts and labeled everything.  Looking forward to finishing this build!

- Alex W3APW

Re: Pre-wound Toroids

Gary Bernard
 

LOL big time.


-----Original Message-----
From: Richard Lawn <rjlawn@...>
To: QRPLabs <QRPLabs@groups.io>
Sent: Fri, Apr 3, 2020 1:03 pm
Subject: Re: [QRPLabs] Pre-wound Toroids

Can you hear me laughing!

On Fri, Apr 3, 2020 at 2:25 PM Arv Evans <arvid.evans@...> wrote:
Winding toroids could be an execelent way to introduce kids to ham radio.

_-_


On Fri, Apr 3, 2020, 11:57 AM Richard Lawn <rjlawn@...> wrote:
Thanks guys. I’ve used him before with other kits. 

73
Rick, W2JAZ 

On Fri, Apr 3, 2020 at 1:29 PM Michael N6MST <mthompson.cob@...> wrote:
Mychael AA3WF does exactly this. He is the go-to guy for pre-wound toroids. He will wind to your specs for a fee and he does very good work. You can email him at toroidguy@...
--