Date   

Re: Shortage of Si5351A

Paul WB6CXC
 

Jim, thanks for this.  I needed some '5351's and yes, the distributors were definitely out of stock.  I was able to use Chipmail (as "guest", no registration needed), and ordered 50 of the Chinese equivalents.  I will report back on the performance -- I'm especially interested in the spur filtering behavior.
--
Paul Elliott - WB6CXC


Re: QCX Mini for 17M - usability on 20M & 15M? #qcxmini

HF
 

Hi David,
Is there room in the Mini's filter to install a pair of those square posts with 0.1-inch spacing?  If yes, then maybe the capacitance in the filter could be changed when changing bands.  I'm quite keen to hear about what you do to achieve this and how well it works.  I wish to do something similar with my 17m Mini.
Cheers
Halden VE7UTS


Re: QRP Field Day

Gwen Patton
 

There are lots of small solar panels that are already set up with the necessary charge controller to charge a USB power bank. If you get a Power Delivery or Qualcomm Quick-Charge power bank (or two, one to use, one to charge) and the necessary trigger cable or circuit, you can use one of those power banks to power your QCX+ just fine. I've been doing it for over a year now, and others have replicated my work and achieved good results. That's one of the benefits of using a USB power bank for your radio's power -- there are lots of charging options already configured to work with it.

You can find all the particulars on my ham blog, at https://www.ng3p.com. I also have some links to suitable power banks, though if you're in VK-land, you might have better luck looking for them locally. Just make sure that the supported PD and/or QC output voltages contain 12V. I've found that my QCX (original, not +) works just fine on 1-1.5A. I tested it on my workbench's compromise antenna (a QRPGuys "no tune" 40m end-fed, run from my porch to a tree out front) and routinely get RBN responses from halfway across North America. I don't bother fellow hams with responding to my tests, they've got better things to do, so I just send testing calls for RBN to pick up and report. There are plenty of links and search terms on my blog for the special cables that will request the power you require from the power bank and pass it on to your radio. (This is NOT a buck-boost circuit. There's no RF birdie generated by the cable's circuitry.) The blog also points to a recent presentation on this system that I gave to my local ham radio club.

I usually bring either a Wolf River Coils vertical, a different end-fed wire with a built in QRP tuner, or my 40/30/20 pre-tuned linked dipole when I work in the field. I bring an Elecraft T1 tuner, though I rarely need to use it, and an MFJ color display antenna analyzer to make sure the Wolf River vertical is tuned properly. My goal is to build the QCX-mini I have waiting on my bench, make a custom antenna for it, pre-cut for the band segment I want to use, and a dedicated PD or QC power bank. For that setup, I plan to do what you did, and use field expedient support systems (aka "trees") whenever possible, though I do have a couple of 7.2m telescoping fishing poles. One of them, some micro-paracord, and a few thick wire stakes would do just fine as the high end of an end-fed, or the center of a dipole. I have 150 feet of Kev-Flex wire I've been saving for an antenna that needs a lot of tensile strength, and given that Kev-Flex is tinned copper wire wrapped around a Kevlar core, it should work well for a 40m dipole.

-=-=-=-=-=-=-=-=-
73,
Gwen, NG3P


Re: QRP Field Day

K9NUD-Steve
 

My home power setup is a set of four solar panels that charge a LiFePO battery harvested from a wind farm. I have it set up with 24v battery power and I use a buck converter at my desk to get it to 13.8V for the radios, lighting, and soon the PC. I am building a power wall using a bunch of harvested 18650 cells in stacked boards (Jehu Garcia design). This will likely replace the LiFePO battery, which appears to have a bad cell or two.

I have an inverter, but it puts out a ton of RFI. I'd prefer to run everything using DC to avoid conversion losses. Modern PC monitors often have a 12V input, and I can run my laptop from a USB-C board connected to the 24V feed. The goal is to have the entire shack on solar/battery. 

I run the QCX Mini from a smaller 12.6V 3S board. It also stacks, so I went the whole weekend on that battery pack.


Re: QRP Field Day

wa8yan.radio
 

Amen!  Me too !



Sent from my Verizon, Samsung Galaxy smartphone


-------- Original message --------
From: VK5EEE <vk5eee@...>
Date: 6/28/21 2:38 AM (GMT-05:00)
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] QRP Field Day

Can anyone recommend reliable solar panels that can be portable but also used long term at QTH and what they could best charge with QCX? And where to get the entire set up (panels, batteries, charger circuitry)? Or what various options there are, where can I do some reading into this and options? New to all this, thanks.

On 28 Jun 2021, at 04:47, Tony McUmber <1tonymc@...> wrote:

Great fun, yes?

I don't exactly have a go kit, but I can collect coax, a Z-match, 2 X QCX+ (40, 20), a random sort of dipole I use for both bands (straight for 40, with Z-match for 20, a solar game-camera charger and a 12-V gel-cell battery along with assorted odds and ends into a standard briefcase and a small canvas grocery bag.  Hauled all of this to my screened-in porch (for 'roughing-it' effect), and threw up the antenna between a couple of trees.  Made 100 contacts between the two, with bonus points for solar power.  Great fun, yes!

p.s - I copied the FD message from ARRL also, with a little help from the QCX+ decoder.


--
Love 30m and CW?
http://www.30cw.net


Re: QCX Mini for 17M - usability on 20M & 15M? #qcxmini

Ian MM0GYX
 

Oops, I talked about return loss but didn't copy the correct screengrab, here's return loss and transmission from Elsie:


Re: QCX Mini for 17M - usability on 20M & 15M? #qcxmini

Ian MM0GYX
 

Dave,

Maybe you are familiar with a program called Elsie, if not, it makes designing various filters quite straightforward. W3NQN mentions it when he wrote the article in QST about his BPF design using trifilar and quadrifilar resonators. Anyway, it's available for free download from Tonne Software, you may find it helpful.

I don't have a QCX mini, but I notice the kit uses the standard W3NQN design LPF for 17m, see the screenshot below. Assuming the LPF is terminated at each end with 50 ohms (which is what this design implies) you can see that it would have good return loss upto 17m band, but things look less good as you approach 15m. It's possible 20m 2nd harmonic suppresion may not be adequate possibly.



You could try it, but you might like to monitor for that emissions problem associated with 20m band (I don't know the strength of the 2nd harmonic without the LPF, maybe the 17m filter would be okay, until measured, who knows?), but perhaps there's an alternative? This cauer-ised version of the 17m filter might suite you better, it certainly would be a better choice 17m LPF for running up to 15m, return loss looks okay. http://www.gqrp.com/Datasheet_W3NQN.pdf

Good luck.

Ian MM0GYX


Re: QCX Mini for 17M - usability on 20M & 15M? #qcxmini

Daimon Tilley
 

I cannot comment on your specific band query, but I can tell you that following a facebook post by another OM, I tried my 20m QCX Mini on 30m and it works beautifully on both. My original QCX 40  was no good on 60 or 30m however. Hope that helps a bit unless someone can give you a definitive. 


Re: QCX Challenge - June 2021

N3MNT
 

US is very quiet this am.  Guess everyone is radioed out from FD.


Re: ProgRock serial interface

Syd
 

Thanks, that's what I did. Good to know anyway.
syd/wt1v


Re: QCX Mini for 17M - usability on 20M & 15M? #qcxmini

David Feldman
 

If some person with 17M QCX MINI wishes to perform experiment and consider result, that will be helpful!

I think three basic parameters of interest:

1. Receive MDS (minimum detectable signal)
2. Transmit spectral purity (harmonics and possible other spurious output)
3. DC power consumption during transmit (to see if thermal artifact in final amplifier stage due to efficiency change)

Approximate frequency ratio 18.1/14.0 = 29%, 21.0/18.1 = 16%

I do not expect optimization of performance, just curious circuit survivability and basic usability at reduced specification (=better than carry 3 radios!)

73 Dave WB0GAZ wb0gaz@yahoo.com


Re: QCX Challenge - June 2021

John Pagett G4YTJ
 

I hope to be on 40m for the 1300z session.
73
John
G4YTJ 

On 27 Jun 2021, at 19:19, ON7DQ Luc <on7dq@...> wrote:

Hi Folks,

Sorry for the late announcement, but I just came home from a short SOTA tour.

Tomorrow is the last monday of June, so it's time for the QCX Challenge, see
http://www.qrp-labs.com/party.html

Not sure if I will be in the 1300Z sesion, but I should be QRV for the 1900Z one.
You all have fun !
 
73,
Luc ON7DQ


Re: QCX Mini for 17M - usability on 20M & 15M? #qcxmini

Curt wb8yyy
 

Dave

If you examine multiband rigs you will see that they employ a low pass filter typically for 2 adjacent bands. When properly adjusted for harmonic suppression I suspect in should do 20m. On 15m it would be operating into mismatch not ideal. Best way to see this is looking at filter response for the 17m filter, the rsgb article referenced by Hans may have the plots.  The tuning of the class E transmitter is another factor. Receive on 15m might be reasonable with just a few dB of loss. 

Curt


Re: QRP Field Day

 

Can anyone recommend reliable solar panels that can be portable but also used long term at QTH and what they could best charge with QCX? And where to get the entire set up (panels, batteries, charger circuitry)? Or what various options there are, where can I do some reading into this and options? New to all this, thanks.

On 28 Jun 2021, at 04:47, Tony McUmber <1tonymc@...> wrote:

Great fun, yes?

I don't exactly have a go kit, but I can collect coax, a Z-match, 2 X QCX+ (40, 20), a random sort of dipole I use for both bands (straight for 40, with Z-match for 20, a solar game-camera charger and a 12-V gel-cell battery along with assorted odds and ends into a standard briefcase and a small canvas grocery bag.  Hauled all of this to my screened-in porch (for 'roughing-it' effect), and threw up the antenna between a couple of trees.  Made 100 contacts between the two, with bonus points for solar power.  Great fun, yes!

p.s - I copied the FD message from ARRL also, with a little help from the QCX+ decoder.


--
Love 30m and CW?
http://www.30cw.net


Re: dummy load to attenuator mod #dummyload

 

Good suggestions WA8YAN. I got it right but had to keep double checking. That'd be an easy way to not get mixed up. However, I did once put a large component like a BNC or whatever, on the wrong side ox a board only to laugh at my mistake when I realized lol. So one might then also have the wrong "up and down" :) but yes, it is a dummy load project hehe

On 27 Jun 2021, at 21:32, wa8yan.radio via groups.io <wa8yan.radio@...> wrote:

Yup

Lead dummy
WA8YAN



Sent from my Verizon, Samsung Galaxy smartphone


-------- Original message --------
From: Arv Evans <arvid.evans@...> 
Date: 6/27/21 4:48 PM (GMT-05:00) 
Subject: Re: [QRPLabs] dummy load to attenuator mod #dummyload 

In a lame attempt at humor, perhaps someone should point out 
that it is a "dummy" load project.  8-/

Arv
_._


On Sun, Jun 27, 2021 at 1:10 PM wa8yan.radio via groups.io <wa8yan.radio=yahoo.com@groups.io> wrote:
Perhaps it would also be better to say "do not install on the board the BNC connector is on" rather than top board, bottom board since top and bottom are relative to how you are holding it.  (I'm saying that was my error..... even though I'm sure it wasn't) HI HI.
73 Phil WA8YAN



Sent from my Verizon, Samsung Galaxy smartphone


-------- Original message --------
From: "KEN G4APB via groups.io" <lfoofui.nbz42=ntlworld.com@groups.io> 
Date: 6/25/21 4:14 PM (GMT-05:00) 
Subject: Re: [QRPLabs] dummy load to attenuator mod #dummyload 

Note to Hans and potential builders;
3.4 Fit jumper W2-W3 on the top PCB
Fit a jumper wire at W2-W3 on the TOP PCB only.

But,  the picture shown is the bottom board with the bnc connector fitted!
Confused me for a while!!!!
73 Ken g4apb 




--
Love 30m and CW?
http://www.30cw.net


Re: QCX Challenge - June 2021

HB9FIH
 

Will be QRV from Samos
as SV8/HB9FIH
13 / 19 on 20m
GL
--
---
73 de Erich

HB9FIH

HS0ZLS


QCX Mini for 17M - usability on 20M & 15M? #qcxmini

David Feldman
 

I am interested in using a QCX Mini primarily on 17M, with secondary use (without modification, just changing VFO frequency) on 20M and 15M bands.

Can a QCX Mini configured for 17M be used on 20M and 15M bands with some (how much?) compromise in RF performance in receive (sensitivity), transmit (spectral purity, insertion loss), or both?

Manual version 1.05 section 6.7 (regarding receive bandpass filter behavior) suggests to me that the roll-off of the receive bandpass filter for 17M is a few dB at 20M and 15M bands, which represents a loss of sensitivity that would be OK with me.

Manual version 1.05 section 6.6 (regarding transmit low pass filter behavior) refers to a page discussing Ultimate 3S, however, it is not so clear to me to what extent the low pass filter is effective (or perhaps has excess insertion loss) in this situation.

Thank you for any advice,

73 Dave WB0GAZ wb0gaz@yahoo.com


Re: QRP Field Day

Tony McUmber
 

Great fun, yes?

I don't exactly have a go kit, but I can collect coax, a Z-match, 2 X QCX+ (40, 20), a random sort of dipole I use for both bands (straight for 40, with Z-match for 20, a solar game-camera charger and a 12-V gel-cell battery along with assorted odds and ends into a standard briefcase and a small canvas grocery bag.  Hauled all of this to my screened-in porch (for 'roughing-it' effect), and threw up the antenna between a couple of trees.  Made 100 contacts between the two, with bonus points for solar power.  Great fun, yes!

p.s - I copied the FD message from ARRL also, with a little help from the QCX+ decoder.


10W Linear Bias Setting

Mark M
 

Greetings all...

Just a quick question to be sure I did it correctly...

I assembled the QRPLabs 10W linear amp kit I bought a while back. I'm planning to use it with the µSDX I built a few months ago. I powered it up and no smoke came out so I went ahead and set the bias. With both pots counterclockwise (anticlockwise) it was drawing 70 mA. I turned one of the pots until it read 195 mA. Then I turned the other one until it went up another 125 mA, to 320 mA. Is that correct? I believe so but want to sure I read it correctly. Just me overthinking something, as usual.

Thanks...

--
73...      Mark     AA7TA


Re: ProgRock serial interface

Mont Pierce KM6WT
 

Here's another view showing the pins soldered to and dupont jumpers connected:


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