Re: QCX-mini update

Glenn ODonnell

Hans, you are a genius!

I own three QCX Classics (30, 20, and a recent 80 build). I love them all! I have been contemplating a QCX+ but the mini looks so cool, that my next unit will be a mini! One for 40m would complete my QRP family and I'll then retire my trusty old MFJ-9040. I can't wait to retire so I can play with them more!

Thank you for all you do! You are a fabulous asset to the ham radio community!

VY 73 de Glenn K3PP
now ... about that QCX Pico ... hmmmm, intriguing if my old eyes were better 😊

Re: Orders update

Joe

Got my clock yesterday. Thanks, Hans. Joe, KC4ONU

Re: QCX+ T1 Toroid Wire Length? #20m #qcx+

geoff M0ORE

I really don't know why so many builders seem to have a problem finding out how much wire is needed when winding a toroid.

A simple bit of maths will give you the length required.

Measure the height of the core, then measure the thickness of the core. Add these two measurements together and multiply by two. Now multiply again by the number of turns, add 10% for terminating and loss through the radius of the bends.

DL5SWB passed away in 2014 but his mini programs live on.

On 12/09/2020 13:09, Al Holt wrote:
I've been using "mini Ring Core Calculator" (mRCC) software by DL5SWB for toroid winding info. It also has the reverse, turns-to-inductance, mode which then can be plugged into its main calculator to get wire length.

For a 20 meter T1 with 39 turns (30 plus 3-3-3), mRCC reports that as 7.453 uH on a T50-2 core and the length will be 58 cm. I'm going to stick with metric to make adding it all up  easier.

But you need to add the additional loop lengths and the start and end lengths. Hans says have about 3cm for the start length.

For the loops figure between 10 to 15 cm (5-7.5 cm out and back) for each loop. So, worst case here, an extra 45 cm for the three loops.

That gives us: 5 + 58 + 45 + 5 =  113 cm (~44.5 inches). You'll probably wind up with a few extra cm's, but you bought that spool, right? Always a good idea to have the extra wire!

That's the method I use. PLEASE, check the math and download the software! An extra set of eyes and grey matter always helps!!

Good luck!

--Al
WD4AH

Re: QCX+ T1 Toroid Wire Length? #20m #qcx+

Al Holt

I've been using "mini Ring Core Calculator" (mRCC) software by DL5SWB for toroid winding info. It also has the reverse, turns-to-inductance, mode which then can be plugged into its main calculator to get wire length.

For a 20 meter T1 with 39 turns (30 plus 3-3-3), mRCC reports that as 7.453 uH on a T50-2 core and the length will be 58 cm. I'm going to stick with metric to make adding it all up  easier.

But you need to add the additional loop lengths and the start and end lengths. Hans says have about 3cm for the start length.

For the loops figure between 10 to 15 cm (5-7.5 cm out and back) for each loop. So, worst case here, an extra 45 cm for the three loops.

That gives us: 5 + 58 + 45 + 5 =  113 cm (~44.5 inches). You'll probably wind up with a few extra cm's, but you bought that spool, right? Always a good idea to have the extra wire!

That's the method I use. PLEASE, check the math and download the software! An extra set of eyes and grey matter always helps!!

Good luck!

--Al
WD4AH

Re: QCX+ RF Power

David Griffiths

I took one turn off L1, 2 and 3 but it made absolutely no difference to the RF output.
I don't think I want to take another turn off as I don't like too much rework on the pcb.

David
G4DMG

Re: Low Pass Filer Board Timing.

Phil Crockford

I have checked this and when a slot transmission ends all BPF select lines go high and remain high until the start of the next slot in the frame.

Thanks for the thought.

Phil G8IOA

From: QRPLabs@groups.io [mailto:QRPLabs@groups.io] On Behalf Of KEN G4APB via groups.io
Sent: 10 September 2020 07:39
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] Low Pass Filer Board Timing. #U3s #bpf #wspr

Hi Phil, I think the way it all works is the lpf is selected prior to the next transmission slot as soon as the last transmission finishes. I.e, in the case of wspr transmissions, there are a few seconds gap so the next lpf/relay in sequence is selected and so has no time delay before start of the next transmission.
73 Ken G4APB

Re: QCX-mini update

Alan G4ZFQ

When can we pre-order this new postage stamp QRP radio?
Yes! Better than a smart watch, a QRP watch!

73 Alan G4ZFQ

Re: QCX-mini update

namerati@...

On Fri, Sep 11, 2020 at 11:42:29PM +0300, Hans Summers wrote:
If we could have a 5W
radio the size of a postage stamp, would it be all that practical to squint
at the tiny screen and operate it?
When can we pre-order this new postage stamp QRP radio?

Re: QCX+ Resistor hot

Alan G4ZFQ

I find that R48 (270 ohms) on the readout display board is quite hot. With a 13.8v source, I measure 8.57v across the resistor. This is 0.27 watts dissipation.
It feeds the backlight.
And, indeed you would expect about that dissipation. Seems a lot but must be normal.

73 Alan G4ZFQ

QCX+ Resistor hot

K3YV

Hi everyone. I find that R48 (270 ohms) on the readout display board is quite hot. With a 13.8v source, I measure 8.57v across the resistor. This is 0.27 watts dissipation. That is rather marginal for a 1/4 watt resistor. I checked the resistor, it is indeed 270 ohms. Do I have something misassembled, or is this normal? Thanks all.

Re: 30m QCX+ and QCX+ Enclosure for sale

Michael N6MST

Re: QCX+ T1 Toroid Wire Length? #20m #qcx+

ke9uw

I actually used this...

https://toroids.info/
took me awhile to find it again. But it’s pretty handy. Just put in the # of turns and press calculate

Re: QCX Mini Upgrde ...

Mark Garrisi

On the paddle conversation, I purchased the DCP paddles from American Morse. It went great with my QCX build...
On Sep 11, 2020, at 5:03 PM, namerati@mailo.com wrote:

﻿On Fri, Sep 11, 2020 at 08:37:53PM +0100, Andrew Cunningham via groups.io wrote:
Hans ...

Loved the video ... will watch it over & over I know

Can we have a “ Micro CW Key “ from Brass or Alu ... maybe to go along with the radios
I agree, especially as the Pico Paddles are no longer in production!

( Use & Love My KK5PY Micro Te-Ne-Ke )

http://g0mwt.org.uk/skills/cars-skills-aug2015.htm?LMCL=H7gKGd

Dunno if you’ve implemented “ Continuous Drive Control “ Yet with the aid of a Linear Pot Switch or Flick Switches

But I still think this a great, neat idea ... particularly for folks wanting to really push the challenge both in & outdoors

Up The Mountains Of Our World-Audience with this

“ Easy To Achieve dB Cut-Back “ Feature would be a great selling point

I’m a REAL QRPp Freak As well as QRP who hasn’t tried QRPp yet but is dyin to go -

Just can't find “ An easy minimalist way of achieving this “

From the confines of my Bed ! Due to health issues

Before I go Hans - What QCX’s On HF Bands as selling point are still available I have few Bands I’d love to fill

Thanks Man For All The Years Of Excellent Work

Sent From Andy - GM0NWI’s iPhone

Re: BPF 80m

geoff M0ORE

Just to be pedantic and I appreciate that English is not everyone's first language ( and this will result in a lot of comments to give me something to read now we are in a lockdown situation again ), a negative loss is a gain.

Hence "-5dB insertion loss" is a 5dB gain.

Have a good weekend.

On 11/09/2020 21:42, DL2ARL wrote:
Hello group,
well... not wanting to stay theoretical, I implemented the thoughts  in the message above #43560 and cascaded the Low Pass Filters (LP) sitting on the filter switch board of the U3S with static, non-switchable HighPass FIlters sticking into the Rx PinHeaders where a BandPass is supposed to go to.

What I was curious to see is what the difference is between this combo and the standard, official BandPassFIlter (BP). From these I only built one for 80, but it is enough for the question here.

This is what I got:

The picture below should be self explaining. Important are the red (BP) and the green (LP&HP) curves. The other two curves are the "root" of the LP&HP combo, the individual frequency responses of the original LowPass from qrp-labs and my own HighPass based on the same idea, but with nervous coefficients (Cheby instead Butterworth). Cascading the filters yields the green curve.
Compared to the red BandPass filter.... well there is no free lunch. I could have pulled the skirts of the two filters nearer to each-other, but the combo depicted here perfectly fits my needs, for a while...

About the -5dB insertion loss of the original BandPass.... there is somewhere in this net an ongoing discussion. Some said that you might need "heavy" groundplanes below the filter when measuring it. I did the experiment, with and without "heavy" groundplanes and must say that I do not subscribe to this oppinion, without wanting to start a chest-beating discussion here (the coupling cap used is thea standard one prescribed by the manual.. I recall 47pF).

This is what I got, your mileage might vary. I need this configuration of cascaded filters NOT as a big improvement (because it is obviously not a betterment), but because this is what I need at the moment. For dedicated setups on single bands I will probably build other and other U3S and corresponding Rx'es. It is so much fun!

Yours friendly, Razvan DL2ARL

Re: QCX+ RF Power

David Griffiths

Thanks Ronald, Actually after winding L1, 2 and 3 they measured about 10% high on my Peak LCR45 so I took a turn off, they were still over the nominal inductance.

I will read Hans' troubleshooting guide again.

David
G4DMG

Re: QCX-mini update

Jim Manley

Hi Hans,

As for the postage stamp sized "QCX Pico" that you just "announced" (I claim dibs on the first production unit!), I only have one word to say in regards to how to view such a tiny display: PROJECTION! :D

Jim  KJ7JHE
Lame Deer Montana High School Amateur Radio Club  KJ7JKU

On Fri, Sep 11, 2020 at 1:42 PM Hans Summers <hans.summers@...> wrote:

Almost, but not quite small enough to fit in an Altoids tin...
Have you considered 402 parts???
But, the hard part is getting the height thin enough....

There's not much point going to 0402. It has to be big enough to hold the LCD and have space for the controls below that. Or do something much more radical which would be an out-of-scope redesign. If we could have a 5W radio the size of a postage stamp, would it be all that practical to squint at the tiny screen and operate it?

73 Hans G0UPL

Re: QCX Mini Upgrde ...

namerati@...

On Fri, Sep 11, 2020 at 08:37:53PM +0100, Andrew Cunningham via groups.io wrote:
Hans ...

Loved the video ... will watch it over & over I know

Can we have a “ Micro CW Key “ from Brass or Alu ... maybe to go along with the radios
I agree, especially as the Pico Paddles are no longer in production!

( Use & Love My KK5PY Micro Te-Ne-Ke )

http://g0mwt.org.uk/skills/cars-skills-aug2015.htm?LMCL=H7gKGd

Dunno if you’ve implemented “ Continuous Drive Control “ Yet with the aid of a Linear Pot Switch or Flick Switches

But I still think this a great, neat idea ... particularly for folks wanting to really push the challenge both in & outdoors

Up The Mountains Of Our World-Audience with this

“ Easy To Achieve dB Cut-Back “ Feature would be a great selling point

I’m a REAL QRPp Freak As well as QRP who hasn’t tried QRPp yet but is dyin to go -

Just can't find “ An easy minimalist way of achieving this “

From the confines of my Bed ! Due to health issues

Before I go Hans - What QCX’s On HF Bands as selling point are still available I have few Bands I’d love to fill

Thanks Man For All The Years Of Excellent Work

Sent From Andy - GM0NWI’s iPhone

Re: QCX-mini update

namerati@...

Edge mount would be quite alright, though the edge mount SMA connectors I have used were designed for slightly thinner microwave boards and did not fit standard FR4.

I also notice that you managed to match the dimensions of the MTR3b almost down to the millimetre :)

On Fri, Sep 11, 2020 at 10:35:51PM +0300, Hans Summers wrote:
Good point, I forgot that. Thanks for fhe reminder. I must see if I can put
them in. Edge mount? How can that work... the edge is up against the
enclosure wall.

73 Hans G0UPL
http://qrp-labs.com

On Fri, Sep 11, 2020, 22:31 <namerati@mailo.com> wrote:

No alternate pads for an SMA connector?

On Fri, Sep 11, 2020 at 07:23:16PM +0300, Hans Summers wrote:
Hi all

I am excited to provide an update on the QCX-mini project
http://qrp-labs.com/qcxmini.html

Again to stress: QCX-mini has the same schematic (almost), firmware,
operation and performance as QCX and QCX+. It is just a different physical
manifestation. This is not a major R&D effort. It is a pleasant breather.
The tasks are limited to mechanical re-engineering and some
re-documentation later. So please don't all start yelling at me about what
I ought to be spending my time and energy on instead.

To summarize: I laid out a PCB. Two in fact (it's a sandwich). And got
some
made. I have ordered two sets of components and one set arrived yesterday;
the other (the bulk of the R and C, SMD parts from Farnell UK) will arrive
in about 1 week. I designed an enclosure and made technical drawings, and
my usual enclosure factory has produced a prototype to my specification,
which is in the post and will likely get here in about 2 weeks from now.

So far everything fits together very well and at this stage I do not

It's a really beautiful little radio! I am looking forward to hauling
myself to a nearby mountain to try it out.

73 Hans G0UPL
http://qrp-labs.com

Re: QCX-mini update

The Crunchbird

Hans, we have no mountains in Florida but I would love to take one to the beach, Dave. N2SN

Re: QCX Mini Upgrde ...

Hans Summers

Hi Andy

Get well soon OM, all my best wishes...

Before I go Hans - What QCX’s On HF Bands as selling point are still available I have few Bands I’d love to fill

There are no more QCXs here. Only QCX+.

We have some assembled QCX+ (i think this is what you're asking) in the shop, see http://shop.qrp-labs.com/assembled

If you need a particular band that you don't see available then if you email me, I can help arrange it.

73 Hans G0UPL

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