Date   
USB to Serial (TTL) Converter

Dave, W0DF
 

What are people using for the USB to Serial converter for CAT control of the QCX's?  Can anyone make a suggestion please?

Dave, W0DF

Re: QCX Not-A-Case

Shirley Dulcey KE1L
 

Shielding mostly matters if you are in a noisy RF environment, as many modern homes are nowadays because of the plethora of electronic devices. A SOTA operation is probably about as quiet an RF environment as one can find on land in the modern world (in the HF spectrum anyway; I'd expect to see a lot of microwave RF from relays and cell towers), so I wouldn't expect RF shielding to have a lot of benefit there.


On Sat, Dec 14, 2019 at 1:58 PM Dan Pflugrath <dpflugrath@...> wrote:
I have made several cases out of poly carbonate sheet, two uBITX and a QCX.  Not sure how much of a difference metal shielding would have made but have made hundreds of contacts with these radios backing them up to many SOTA summits.  The material machines easily without cracking, can be drilled and taped, is almost indestructible, is light weight and the adhesives used for this material make the joints permanent.   See my QRZ page.  73, Dan KA7GPP

Re: QSX

Andrew K8AKC
 

Great writeup, thanks for taking the time to update us on what is going on. As a poor, but tech-minded ham, I am very looking forward to this radio. Keep up the good work!

Re: QCX Not-A-Case

Brent DeWitt
 

Glad you asked.  For 45 years or so, until last April,  my professional engineering specialty was electromagnetic compatibility, so I have my strong opinions about grounding and shielding.  I only have two rigs; the QCX and SoftRock RXTX Ensemble (1 watt out).  In my case, it simply doesn't matter.  The Softrock is connected to 120' end fed long wire and the QCX feeds and OCF dipole, both out the same window.  I can see the L.O.s from one unit to the other, but, for all practical purposes, it's all coming through the antennas.  The only hassle with the QCX is 120 Hz hum if my finger tip hits the wrong resistor on the AF gain stage!

Have fun, it's all small stuff!
--
Brent DeWitt, AB1LF
Milford, MA

Re: QCX Not-A-Case

Wes AE6ZM
 

Now that is thinking "out-of-the-box"! Well done!
--
> I finally got it all together...now I can't remember where I put it<

VY 73,
Wes

AE6ZM

Sierra Vista, AZ

 

50 watt PA @20 VDC Power Supply #pa

Rick Williams - VE7TK
 

So I'm considering the new amp and was slowed somewhat by the 20 VDC power supply requirement. Yes I know it will run at 13.8 VDC but another 3dB output would be nice.

Now my wife, Doris, is always asking if I REALLY need all those "wall warts" that are in a box in the laundry room. Well today I went through that box and I found a few 19 VDC @ 7 amp laptop computer power supplies. As I remember I kept these switching supplies when I upgraded computers because they seemed to be reasonably RF quiet.

If it was good enough for HP hopefully it will work for me!!
--
73, Rick
VE7TK

Re: QCX Not-A-Case

Dan Pflugrath
 

I have made several cases out of poly carbonate sheet, two uBITX and a QCX.  Not sure how much of a difference metal shielding would have made but have made hundreds of contacts with these radios backing them up to many SOTA summits.  The material machines easily without cracking, can be drilled and taped, is almost indestructible, is light weight and the adhesives used for this material make the joints permanent.   See my QRZ page.  73, Dan KA7GPP

Re: QCX Not-A-Case

Bill Cromwell
 

Hi,

Besides physical strength a metal cas provides shielding which is helpful for transmitter AND receiver. Most people are too timid to try and shape metal. The printed or molded plastic cases can be really *pretty* but off no shielding at all. You can use one of the heavy aluminum baking pans to form an internal metal case. The aluminum is easily formed by hand and heavy enough to hold it's shape well. Wash and re-use the aluminum pan your frozen dinners are packaged in or just buy new pans at your local grocer. When installed in the pretty store-bought or home printed plastic case you get a *pretty* radio with good shielding. Nobody will be seeing the possibly ugly shields:) I have used it to place additional shielding between stages inside store-bought radios.

I fold new sheet steel for mine but I admit those plastic cases are attractive:)

73,

Bill KU8H

On 12/14/19 9:59 AM, Jon wrote:
Nice!
I usually see people using a metal case.  Your "not-a-case" makes me wonder if the metal case provides some benefit or is a plastic case or no case just as good?  Does the answer vary if the xcvr is low power or higher power?  Are there other factors to consider when choosing a case material?
73, Jon KE5URU
--
bark less - wag more

Re: New kit: 50W PA for QCX

Hans Summers
 

Hi Richard
 
My LibreOffice (6.3.3.2) has English (UK). This is on Windows 10 - are you on Linux? I don't know if that makes a difference.

I am on Linux yes. I am sure I can easily load the dictionary for English (UK). I think it is probably on English (USA) because I must have selected US defaults when I initially installed the OS. Probably because I use a US keyboard. I got used to the US keyboard during my Japan years (2011-2016) because that was what we had at my employer's office. Can't change back now :-/ 

73 Hans G0UPL

Re: New kit: 50W PA for QCX

K9WIS
 


so do I make the check out to QRPLabs   or Labs...

hi hi

72, Brian K9WIS

-----------------------------------------

From: "Hans Summers"
To: qrplabs@groups.io
Cc:
Sent: Thursday December 12 2019 4:59:49AM
Subject: [QRPLabs] New kit: 50W PA for QCX


Hello all QRP Labbers.. (don't forget to VOTE QRP LABS!)

Here is a new kit, this is a 50W PA kit for the QCX. See http://qrp-labs.com/50wpa . Price is $29.50 (approx £22 or 26€) which includes the PCB, all components and connectors, and two large black anodized aluminium heatsinks. The amplifier produces up to 50W power with full break-in (QSK), with 20V 5A supply. At 13.8V supply on 40m CW the measured power output is 25W. 

A beautiful enclosure for it is also available, price $16 (approx £12 or 14€), see http://qrp-labs.com/50wpabox . It is made from black anodized extruded aluminium with front and rear panels drilled and printed to match the 50W PA. 

A key feature of the kit is fast solid-state transmit/receive switching (relays!) - which allows full break-in (QSK) operation using the QCX. 

The kit can be built for 40, 30 or 20m bands, which covers 90% of QCX kits. It can also be built for other bands if you supply your own Low Pass Filter components. Multi-band would be possible if you connect your own switched external Low Pass Filters. 

Please refer to the FAQ on the 50W PA page http://qrp-labs.com/50wpa if you have any questions. The 68-page manual is very detailed making construction un-daunting, and the manual also also includes a substantial section detailing the circuit theory. 

Despite our dedication to QRP (5W and under), there are occasions when a bit more power is needed, and this kit provides it. For example, you want to QSO a particular station on a sked at a particular date and time; or when conditions are poor, or you want to work particular DX... any number of reasons. 

During the summer of 2019 the 40m version of this amplifier was tested extensively here in QTH KM46, with well over 500 QSOs in the log. Despite the poor band conditions and my very mediocre antenna and location, QSOs ranged from New Zealand and Japan in the East, to US in the West; Finland in the North, down to Saudi Arabia and everywhere in between. (500+ real QSOs averaging 10 minutes, not contest exchanges). During QSOs I estimate around 90% of correspondents are using power in the 50-100W range, the remaining 10% operate with higher power than that or a few of them, with QRP (5W and below). This 50W PA kit puts you and your QCX on a level playing field with the majority of CW operators on the bands.

So pimp your station, pump up the watts... have some fun with a new project... the 50W PA kit http://qrp-labs.com/50wpa 

73 Hans G0UPL

Re: Help with T1 voltage differences.

Albert Rowe
 

Understood, thanks again.

Re: QCX Not-A-Case

Jon <7xSUAZLHhtls@...>
 

Nice!

I usually see people using a metal case. Your "not-a-case" makes me wonder if the metal case provides some benefit or is a plastic case or no case just as good? Does the answer vary if the xcvr is low power or higher power? Are there other factors to consider when choosing a case material?

73, Jon KE5URU

Re: Help with T1 voltage differences.

N3MNT
 

They are individual windings, but some of the legs are connected to common points. so the other ends may appear to be connected ( through winding) once soldered to board.

Re: Help with T1 voltage differences.

Albert Rowe
 

Hi Thanks for that, I wound it as 4 individual windings with the required inner legs pointing straight down and cut in 3 steps so as I lowered it onto the board they each in turn went into their required holes, then the outer ones the same after which I pulled them down to lower the toroid to the boards (having burned and sanded beforehand of course). So assumed they would be individual windings which is how they look to me on the schematic!.

Re: QCX Not-A-Case

jjpurdum
 

Slick!

Jack, W8TEE

On Saturday, December 14, 2019, 8:54:51 AM EST, Brent DeWitt <bdewitt@...> wrote:


I should have mentioned that I uploaded the two photos to the photo section of the groups .io site rather than attach them to the email.  Hope that helps!
--
Brent DeWitt, AB1LF
Milford, MA

Re: Help with T1 voltage differences.

N3MNT
 

Before you pull T1 and rewind it, check the schematic.  Once installed on the board, the windings will not all show as separate.

Re: Help with T1 voltage differences.

Albert Rowe
 

Hi Alan thanks for the reply, I did leave a list of all suggested voltage points the other day with the pictures I uploaded but not sure if they came up, voltages C43, 1.40v, C44 1.83v, C45, 1.71v, C46, 1.50v R2 voltage (wire end) 4.7v, board end 1.8v, Colour code Brown Black Black Red Brown checked with DVM before installation, I have checked T! Several times (each separate winding!), just discovered point 4 centre is making contact with point 2, I assume the coating is damaged somewhere. I will rewind and try again, I had to add 2 turns at point 1 end to achieve the required setting of C1, thanks again.

Re: QCX Not-A-Case

Brent DeWitt
 

I should have mentioned that I uploaded the two photos to the photo section of the groups .io site rather than attach them to the email.  Hope that helps!
--
Brent DeWitt, AB1LF
Milford, MA

Re: QCX Not-A-Case

Don--AE4DW
 

Ok, so maybe I'm the only one missing something here, but..I don't see any photos. And I always love seeing creative "casing" ideas.

Re: Help with T1 voltage differences.

Alan G4ZFQ
 

1.46v points at 5,6,7,8, what factor alters this voltage value please?.
This comes from the potential divider R1/R2.
Have you 5V at R2 opposite end? Are they both 10K? Resistors and T1 soldered well?
It is possible that something at the switch outputs of IC4 might affect this, what are the voltages across C43, 44, 45, 46?

73 Alan G4ZFQ