Date   

Re: QCX-mini update

Michael N6MST
 

Shout out to the Norcal 40A in the background of the QCX Mini video :)


Re: QCX-mini update

namerati@...
 

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
anticipate any major roadblocks.

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

Hans Summers
 

Hi Bob

It's a different pot. Smaller size and green. The pins stick out of the plastic body. More pricey but I needed the small size. See attached.

73 Hans G0UPL 


On Fri, Sep 11, 2020, 22:11 Bob M. <wa1mik@...> wrote:
Looks like a bunch of nice improvements.

From reading lots of posts here, it does seem as if a lot of people had problems with the 5k volume control lugs either disconnecting from the phenolic or losing contact elsewhere. Does your new design address this problem at all, either by a different wiring method or a different pot?

Bob M.


Re: QCX+ mechanical problem

Jim Manley
 

I haven't found it necessary to drill/file/sand any nuts, but I do occasionally find that scratching them to be beneficial during extended build sessions.  Scratching a line on a nut and the PC board helps identify their correct orientation when adequately tightened if I have to disassemble and reassemble boards - what was your mind-in-the-gutter thinking?  I will now return to my hidey-hole to avoid massive incoming flak anyway!


Re: QCX-mini update

Bob M.
 

Looks like a bunch of nice improvements.

From reading lots of posts here, it does seem as if a lot of people had problems with the 5k volume control lugs either disconnecting from the phenolic or losing contact elsewhere. Does your new design address this problem at all, either by a different wiring method or a different pot?

Bob M.


Re: QCX-mini update

Ben
 

Wow, that is a good looking transceiver! For you not a major effort, but man, I am amazed ^_^ Even the alignment pots are reachable. I also like the CAT and PTT ports for when using the rig at home.


Re: Nice power supply for 50 Watt amp

R. Tyson
 

G'day sport,
Thanks for the comment. I like the sense of humour  >:-)

I guess these AC chargers are a few years old so may be better than new stuff.

73's
Reg          G4NFR


Re: QCX+ mechanical problem

Sheldon Hartling
 

Hi Elwood,

I didn’t find It necessary to drill out any nuts/spacers.  I did however find it useful to cut down two of the nylon nuts.
Details (pictures) here.

73, Sheldon VE1GPY


Re: Thoughts on Low Power and fewer turns on LP filter toroids

Steve in Okinawa
 

Very cool project, Hans. Now who will be the first to make a PPP (permeability power peaker) for a QCX? (And I noted the comment about your earthed soldering iron tip, for only today the mains GCFI blacked out the whole house when I attempted to solder some antenna coax braid.)     73,. Steve


Re: QCX-mini update

Brian George
 

Wow! It sounds absolutely fantastic. Can't wait to get one. Well done Hans - all your efforts are greatly appreciated.

73
Brian
G3ZOH


Re: QCX+ RF Power #qcx

Ronald Taylor
 

Hi  David. On the 20 Meter version, some folks find that removing a couple of turns from L1, L2 and L3 will increase power output, if the issue is a lower than expected power output due to lower than expected cutoff frequency of the lowpass filter. You can also spread or squeeze turns on these toroids to get some improvement. I wouldn't remove more than 2 turns unless you have a spectrum analyzer to verify you are still meeting the spurious output requirements.

This turns removal is mentioned in the last sentence before the conclusion in Hans' troubleshooting procedure. https://qrp-labs.com/qcx/qcxtrouble.html
which is a very interesting and informative read..... 73 ... Ron


On Fri, Sep 11, 2020 at 10:46 AM David Griffiths <davidmgriffiths42@...> wrote:
Across the resistors Evan, before the diode.

David
G4DMG


Re: QCX+ RF Power #qcx

David Griffiths <davidmgriffiths42@...>
 

Across the resistors Evan, before the diode.

David
G4DMG


Re: QCX+ RF Power #qcx

Evan Hand
 

David,
Where are you measuring on the dummy load?  If across the resistors and not the power tap, then your power measurement is correct.  If you are using the Power Connection on the dummy load, that is rectified voltage, so you would use the Vp*Vp/100 to get the approximate power out.  That would then be more like 5 watts.

The most accurate would be across the resistors.

73
Evan
A


Re: QCX-mini update

Dave VE3GSO
 

Very exciting.  Just read the full description including photos and sports car and sunglasses.  I know a CW bicycle mobile practitioner who will benefit. (Not me!)

Dave


On Sep 11, 2020, at 12:23, Hans Summers <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 anticipate any major roadblocks. 

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+ mechanical problem

Bill Cromwell
 

Hi,

Filing a nut to get it to fit is good practice for scratch building gear:)

73,

Bill KU8H

bark less - wag more

On 9/11/20 12:57 PM, K3YV wrote:
Thanks much. I did take your advice but still had to file the nut to get it to fit. All ended well. 73


QCX+ RF Power #qcx

David Griffiths <davidmgriffiths42@...>
 

My 20m QCX+ is working quite happily albeit only on receive so far.
I have been measuring the output with a scope across the QRP Labs Dummy load and with a 12 V supply I am seeing 23.2V peak-to-peak, which I calculate at 1.3W.
At 16V supply this rises to 31.2V or 2.4W.  I don't know if it is relevant but the supply current  goes from 450mA at 12V to 580mA at 16V.

This is somewhat lower than expected, any suggestions gratefully received.

David
G4DMG


Re: QCX+ mechanical problem

N3MNT
 

Once it is assembled as best as you can get it, You will never notice it. 


Re: QCX+ mechanical problem

K3YV <eeb3568@...>
 

Thanks much. I did take your advice but still had to file the nut to get it to fit. All ended well. 73


Orders update

Hans Summers
 

Hi all

Some of you may have been waiting for orders involving any of:
  • QCX+
  • QCX+ TCXO
  • Ultimate3S
  • VFO
  • Clock
  • Si5351A
Since we had at various points in the last week or two, ran out of these kits. The latest batches of PCBs reached me yesterday so everyone here has been busy shipping out the pending orders (over 100) as fast as we can. If yours didn't go today, it should by Monday or Tuesday. 

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


Re: QCX+ mechanical problem

Hans Summers
 

Hi K3YV

This is normal. And not as bad as you say :-)   

I was constrained by the dimensions... the necessary relative positions of the LCD and the rotary controls just left very little room for that bolt and its plastic spacers; nevertheless they are necessary. That's why it is all a bit of a tight squeeze. But it DOES all fit! 

These little white plastic nuts are quite susceptible to the application of unreasonable brutality, just a little violence also known as the application of unreasonable torque to the black screw in each corner of the LCD module, will bring those plastic nuts into line. If you wish you can make the job quite a lot easier by drilling out the thread of the 7mm spacer and one set of 4 nuts (NOT all of them!) using a 3mm or 1/8th inch drill bit. This makes them slide on to the screw more easily and move a bit more so that they easily fit into that tight space by the rotary encoder at the bottom right corner of the LCD module. 

Patience and persistance will win the day. No retreat, no surrender. 

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

On Fri, Sep 11, 2020 at 7:32 PM K3YV <eeb3568@...> wrote:
I just finished the 40m QCX+ radio. I had problems assembling the read-out circuit board.
1. The trouble was with the nylon nut (and black screw) located near the volume control. The nylon nut was simply too large to fit next to the volume pot. I had to file down one side of the nut to allow it to sit next to the pot (R1). Doing this allowed the nut to center on the black screw.
2. Also, the nylon nut that is near the rotary counter, sits on top of a solder pad when drawn tight to the PC board. That does not seem right. Did anyone else have this problem? This is production version 1.05. I just received and built it this week.