Date   

Re: QCX 30m: L2 and Power Drop

 

Well I have an unfortunate outcome to an additional test:

I now tested the QCX-2017-2 at 19V and on key down was surprised to see 4.5W, actually less power than at initial key down at 15V. I kept the key down for 3 seconds and watched the power drop to 3W then suddenly to 0. Yes, I must have blown the final! Lesson learnt: if power is LESS at higher voltage, something is seriously wrong, so don't tranmit further at 19V.

In regards to my below, for when I can order another, I'd still appreciate any comments :)

On 4 Jun 2021, at 14:58, VK5EEE <vk5eee@vkcw.net> wrote:

Greetings All,

2 questions please regarding the QCX-2017-2: :

1) I got power out to 3.7W at 12V effectively doubling the output power by removing 2 turns from L3, and 2 or 3 turns from L1. However:

L2 would increase power when bunching the windings together, so I added 1 turn and power still decreases when the windings are spread out, and only achieves maximum when completely bunched together winding to winding. Does this mean I could add another winding to L2 bringing it to 22? I'm only asking in theory, because this already meets the spec. But it may be relevant to my second question:

2) When I key down for 3 seconds, the power drops 1 Watt during key down. Say at 15V I'm getting 5.5W out, the power progressively drops to 4.5W during these 3 seconds. If I keep holding the key down it continues to drop to 3.5W thus dropping 2W steadily over 10 seconds. Could the cause of this be L2 being so titely bunched together? What should I be looking for? I don't think the power should drop like this.

Thanks for any advice,

73 ES 77 de Lou

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




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


Re: QCX 30m: L2 and Power Drop

jerry@tr2.com
 

Without looking at the schematic in question, I could guess that something
is heating up - maybe the final transistor? And changing its parameters
as it heats. I know that Hfe of a transistor is dependent on the current
density - in general, the more current, the lower the beta. But that wouldn't
explain why the power sags. Could it be that your power supply is marginal?
And when the transmission starts, the filter cap is full? But then it sags?

- Jerry KF6VB

On 2021-06-04 07:58, VK5EEE wrote:
Greetings All,
2 questions please regarding the QCX-2017-2: :
1) I got power out to 3.7W at 12V effectively doubling the output
power by removing 2 turns from L3, and 2 or 3 turns from L1. However:
L2 would increase power when bunching the windings together, so I
added 1 turn and power still decreases when the windings are spread
out, and only achieves maximum when completely bunched together
winding to winding. Does this mean I could add another winding to L2
bringing it to 22? I'm only asking in theory, because this already
meets the spec. But it may be relevant to my second question:
2) When I key down for 3 seconds, the power drops 1 Watt during key
down. Say at 15V I'm getting 5.5W out, the power progressively drops
to 4.5W during these 3 seconds. If I keep holding the key down it
continues to drop to 3.5W thus dropping 2W steadily over 10 seconds.
Could the cause of this be L2 being so titely bunched together? What
should I be looking for? I don't think the power should drop like
this.
Thanks for any advice,
73 ES 77 de Lou
--
Love 30m and CW?
http://www.30cw.net


Re: QCX Amp Complete...

R. Tyson
 

Hi,
I have been using a laptop power supply for several months with my 50w amp. It is 19v 7A. I have only ever used the HP power supplies as they are well screened so can't speak for the rest.

Reg                        G4NFR


Re: TNT Shipping

Al Holt
 

On Thu, Jun 3, 2021 at 04:12 PM, Al Holt wrote:
I got an email today from Fedex' Customs Trade Coordinator about my QLG-2 shipment:

"Good Afternoon, I am working to pre-clear a package for you through US Customs........."
I'd like to answer this correctly so it won't delay the shipment.

Below is a draft of my reply:

"The kit in question is a group of electronic parts needed to make a GPS receiver designed for private use with amateur radio equipment. Here’s a picture of it I downloaded from the kit manufacturer, QRP Labs:

  (inserted a pic of the kit's components)

I’ll itemize a list as you requested:

1. 80x37mm Printed Circuit Board (PCB) 

2. SMA RF connector

3. USB data connector

4. Magnetic-mounting Active-Patch GPS antenna with coax and SMA connector.

 

I don’t have any idea what the HTS Tariff number might be. The “main component” of the kit might be considered the E108-GN01 GNSS receiver module, an electronic part, that is soldered to the PCB.

 

I hope this will help you determine how to classify the shipment.

How well do you think this will work? Am I going to have to pay a tariff on this????

--Al


customized SDR

gammaiotamu@...
 

Hello. I'm looking for someone to build a customized SDR transceiver with unique specifications. If technically competent please contact me by email. gammaiotamu@gmail.com
Thanks!
Gregory, W2/*


QCX 30m: L2 and Power Drop

 

Greetings All,

2 questions please regarding the QCX-2017-2: :

1) I got power out to 3.7W at 12V effectively doubling the output power by removing 2 turns from L3, and 2 or 3 turns from L1. However:

L2 would increase power when bunching the windings together, so I added 1 turn and power still decreases when the windings are spread out, and only achieves maximum when completely bunched together winding to winding. Does this mean I could add another winding to L2 bringing it to 22? I'm only asking in theory, because this already meets the spec. But it may be relevant to my second question:

2) When I key down for 3 seconds, the power drops 1 Watt during key down. Say at 15V I'm getting 5.5W out, the power progressively drops to 4.5W during these 3 seconds. If I keep holding the key down it continues to drop to 3.5W thus dropping 2W steadily over 10 seconds. Could the cause of this be L2 being so titely bunched together? What should I be looking for? I don't think the power should drop like this.

Thanks for any advice,

73 ES 77 de Lou

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


Re: QLG1 Bit the Dust?

Larry Weaver
 

Hi Alan,
     I certainly will when I have the time. I really appreciate the response to my question from Eike and Dean. I can't help but think the slight cost of the componet(s) that could be bad plus shipping might not make it worth it but I certainly do want to know the problem for future reference. I was hoping it was some dumb thing I might have done wrong but I think I'm safe this time.

Thanks again,
Larry


Re: U3S Auxiliary Outputs

John Baines
 

Thanks for that Roger. I knew I’d seen something like that somewhere.

It’s now printed out and filed in my U3S folder.

Thanks again.

73
John
M0JBA

On 4 Jun 2021, at 15:21, Roger G4IUP <rogerlimbert14@...> wrote:

Hi John.
Think you will need to use a transistor as a switch to drive the relay. Hans gives info in AN003 page 4.
73 Roger.


Re: U3S Auxiliary Outputs

Roger G4IUP
 

Hi John.
Think you will need to use a transistor as a switch to drive the relay. Hans gives info in AN003 page 4.
73 Roger.


U3S Auxiliary Outputs

John Baines
 

Hi All,

I am planning to use the auxiliary outputs to operate relays to switch attenuators .

What is the current rating for these outputs?

Thanks in anticipation for your help

73/72
John
M0JBA


Re: QCX Amp Complete...

jerry@tr2.com
 

Ick. Oh well, it is what it is. We'll see. I have a baggie of big Palomar
ferrite cores in my ham junk.

- Jerry KF6VB

On 2021-06-04 05:32, Daniel Conklin wrote:
Those HP laptop supplies are also noisy, sorry to inform you. The
solution for mine was to wrap the DC cable seven times through a large
ferrite toroid. That killed the noise almost completely.
--
73, Dan - W2DLC
Links:
------
[1] https://groups.io/g/QRPLabs/message/66734
[2] https://groups.io/mt/83297980/243852
[3] https://groups.io/g/QRPLabs/post
[4] https://groups.io/g/QRPLabs/editsub/243852
[5] https://groups.io/g/QRPLabs/leave/10312280/243852/1190336630/xyzzy


Re: TNT Shipping

wa8yan.radio
 

Fabulous cartoon.... I know that little old lady !



Sent from my Verizon, Samsung Galaxy smartphone


-------- Original message --------
From: Al Holt <grovekid2@...>
Date: 6/4/21 8:39 AM (GMT-05:00)
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] TNT Shipping

On Fri, Jun 4, 2021 at 08:35 AM, David R. Hassall WA5DJJ wrote:
It looks to me that TNT has hired a new "little old lady in tennis shoes" who is taking her job pre-clearing packages through customs very seriously. 
David,
This cartoon from Charles Addams sums it up pretty well.....


LOL!!

--Al


Re: TNT Shipping

Al Holt
 

On Fri, Jun 4, 2021 at 08:35 AM, David R. Hassall WA5DJJ wrote:
It looks to me that TNT has hired a new "little old lady in tennis shoes" who is taking her job pre-clearing packages through customs very seriously. 
David,
This cartoon from Charles Addams sums it up pretty well.....


LOL!!

--Al


Re: TNT Shipping

David R. Hassall WA5DJJ
 

Dear AL, 

It looks to me that TNT has hired a new "little old lady in tennis shoes" who is taking her job pre-clearing packages through customs very seriously.   This will probably cause a whole new problem of getting our treasured QRPLABS kits from Turkey to the USA.   I am not sure the Pre-clearing of packages is a necessary step in the shipping but all the extra checking and rechecking packages is probably not going to be helpful in the transit process.    What I thought was interesting was there was another message from a ham in Australia that got exactly the same message as you did.   So, that means that she is slowing down the shipping in the whole world and not just to the UNITED STATES OF AMERICA.   Lord help us.   

Take care and have fun.   GOOD LUCK.   I have a package on the way to me and it just says "in transit" whatever that means. 
73/74 Dave WA5DJJ
SUPER GRABBER: http://www.qsl.net/wa5djj/


Re: QCX Amp Complete...

Daniel Conklin
 

Those HP laptop supplies are also noisy, sorry to inform you. The solution for mine was to wrap the DC cable seven times through a large ferrite toroid. That killed the noise almost completely.
--
73, Dan - W2DLC


Re: QCX Amp Complete...

jerry@tr2.com
 

On 2021-06-04 05:14, Paul wrote:
Be aware those cheap switching supplies are exceptionally noisy - use
Yeah, I heard about that AFTER I ordered it. I cancelled that order, and
got on Ebay & ordered a 230W HP laptop supply.

- Jerry KF6VB


Re: QCX Amp Complete...

Paul
 

Be aware those cheap switching supplies are exceptionally noisy - use
a line filter and good grounding.

On Thu, 3 Jun 2021 at 22:15, jerry@tr2.com <jerry@tr2.com> wrote:


On 2021-06-03 18:07, ke9uw wrote:
I bought one of these...
*** OK, I ordered one. It'll be more generally useful than a laptop
supply.
And it's surprisingly small. And light. I still have space under the
desk.
The desk has metal skirts, and I've been sticking stuff to it with super
magnets.

- Jerry KF6VB





Re: CQ WPX CW 2021 with QCX+

John Kirby
 

  Thanks Cristi

""So no fancy "tuner", just an L-match circuit.""

Fancy or not :) hi HI
The Smith chart proves the "simple L"  can match d-c to day-light

72 73
John
N3AAZ


Re: QLG1 Bit the Dust?

Alan G4ZFQ
 

On 04/06/2021 10:56, Dean Smith wrote:
The leds go thru a 74ls08 maybe this is faulty?
If you answer Eike's questions it will help.


Re: Amplifier build adventures

Greg Walters
 

On Thu, Jun 3, 2021 at 02:13 PM, jerry@... wrote:
Instead, I used an AMASS XT60 connector. This is a really elegant, tiny & cheap connector rated at 60A continuous. Sparkfun claims that they will tolerate 65A. They have a round gold-plated pin and a round receptacle. When you plug them together, they inspire confidence. I soldered a couple of short silicone-insulated wires to the circuit board, brought them out through the "DC Power" hole, and soldered them up to the XT60.
That is a great idea, Jerry. I fly RC planes and such and use those XT60 all over those batteries. They are good connectors and can't be plugged in backwards, nor shorted (given that they were soldered correctly). I have used these connectors on other projects as well. 

I still have my QCX+ to build, and may consider doing the XT60 there as well. 
 
--
73,
Greg
KY4GW

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