Date   
Re: QCX Challenge 20m

Hans Summers
 

Hi Erich and all QCX fans 

Small correction: the third session is at 0300Z (UTC) Tuesday morning (Monday evening in US). 

I shall participate in all three sessions on 40m and 20m, as TA4/G0UPL. Most likely mainly 20m at 1300Z and mainly 40m at 1900Z and 0300Z. This is how I've historically found bands tend to be cooperative though Miss Propagation is an unpredictable mistress indeed, so who knows.

72 Hans G0UPL 


On Sun, Sep 29, 2019, 21:23 HB9FIH <erich.rieder@...> wrote:

Hi QCX fans

Tomorrow Challenge, QRV..from TA3 (KM39ii) - CobWeb Antenna, with my QCX 20m on abt 14 060 with Call TA3/HB90FIH

13:00 UTC

19:00 UTC

00:00 UTC no Condx...

Hope I am able to catch some... 73 de Erich

Re: 18650 batteries for QCX

Irv W4IWK
 

allow me to cease operations before the voltage drops to the point that any of the cells is discharged to the point that it’s damaged. Professionals monitor each cell but that’s too complicated for me 
There's a weak cell in every lithium battery.  It's voltage frequently drops sufficiently below the others that it gets damage.  Pack voltage doesn't tell you much.   Li-Ion or LiFePO4 Battery management boards can be found on Amazon for about $15.  That will make your battery easier to build and a lot safer--especially if you're using Li-Ion batteries--you could burn down your house!   Plus, you'll be learning to build it the right way and give yourself a foundation to build your skills on.

Re: QCX power

Irv W4IWK
 

 The TalentCell battery pack is nice at ~$35, not as light as a Bioenno but also not the same price.
Realize that this is a Li-Ion pack and not a LiFePO4 one. 
• Li-Ion are the ones that catch on fire
ª LiFePO4 have less energy density but won't catch on fire.

Keep in mind that, a short in your wiring with any Lithium chemistry battery will put a lot of amps into your wiring and set it on fire.  That's easily solved with a fuse directly at the battery connection.

QCX Challenge 20m

HB9FIH
 

Hi QCX fans

Tomorrow Challenge, QRV..from TA3 (KM39ii) - CobWeb Antenna, with my QCX 20m on abt 14 060 with Call TA3/HB90FIH

13:00 UTC

19:00 UTC

00:00 UTC no Condx...

Hope I am able to catch some... 73 de Erich

Re: Using the LM34 temp sensor with the Shack Clock

Phil N6WKZ
 

Hi Dennis!

Thanks for your response!

I used the 66 and 94 values.

I'm monitoring the LM34 with three different gauges and it seems like the LM34 is about 3 degrees (F) LOW. I checked the LM34 with a known accurate meter and it's spot-on 10MV/1 degree F.

Any ideas?

Would anyone else like to weigh-in ?

73

Phil N6WKZ


On 9/29/2019 8:57 AM, kk5db@... wrote:
This is the method Ii used to change the calibration values from centigrade to Fahrenheit. I got these from a previous post someone made a while back. I saved the information so I could use it for my clock. Sorry I can't credit the original poster.These calibration factors seem to yeild accurate values on my clock thermometer but I haven't checked them against a calibrated source.

0°F = -17.8°c = 500mv + (-17.8°c * 10mv/c) = .322mv
1024 * .322mv / 5 =
66 (ADC value at 0°F)

25°F = -3.9°c = 500mv + (-3.9°c * 10mv/c) = .461mv
1024 * .461mv / 5 =
94 (ADC value at 25°F)

Dennis
KK5DB

 

Re: Using the LM34 temp sensor with the Shack Clock

Dennis Rieger
 

This is the method Ii used to change the calibration values from centigrade to Fahrenheit. I got these from a previous post someone made a while back. I saved the information so I could use it for my clock. Sorry I can't credit the original poster.These calibration factors seem to yeild accurate values on my clock thermometer but I haven't checked them against a calibrated source.

0°F = -17.8°c = 500mv + (-17.8°c * 10mv/c) = .322mv
1024 * .322mv / 5 =
66 (ADC value at 0°F)

25°F = -3.9°c = 500mv + (-3.9°c * 10mv/c) = .461mv
1024 * .461mv / 5 =
94 (ADC value at 25°F)

Dennis
KK5DB

 

Re: U3S pin ID?

John
 

Mike, you are correct. I have examined the foil on the underside of the board and they have a direct connection to the 2,3,4 pins.
Thank you for your reply.

--
Pura Vida

John W Clark
73
TI4JWC   TI4/N0URE  N0URE

Re: U3S pin ID?

John
 

Mike, I do see those markings for the 11 marked points  at the edge of the board. My question is about  the second row that only has holes, The most left is marked 'Key' bit the other 3 are not marked
--
Pura Vida

John W Clark
73
TI4JWC   TI4/N0URE  N0URE

Re: QCX Frequency Memory

Hans Summers
 

Hi Don

To select a preset frequency to load into the VFO:
Dounle-press (quickly) the right button. Then rotate the encoder to find the preset you want. On one side of the screen is "L", press the corresponding button to load that preset frequency into the VFO; on the other side of the screen is "S", pressing the button on that side lets you save the current VFO frequency into the chosen preset frequency memory.

73 Hans G0UPL 

On Thu, Sep 19, 2019, 20:50 Don DeGregori <don1mh@...> wrote:
Push Left button, Preset, and again. Select a memory #. I see what I put in. How to get back to VFO mode with memory frequency I just selected?

Re: 18650 batteries for QCX

Alan de G1FXB
 

AFAIK,
the differences in cell length are because cells may be unprotected or protected terminal construction which give rise to the different physical "standards"


Alan

On 28/09/2019 23:29, Daniel Sloss via Groups.Io wrote:
I?ve learned that 18650 batteries come in both Li-Ion and LiFePo4 models and are slightly different sizes (LP4 batteries are a few mils longer) and also different voltages. For example, LiFePO4 are 3.2V each, at least the ones that I bought through Jaycar. Charging profiles are also different. The good thing about standards is that there are so many of them. Forearmed and forewarned.. Dan VK2NAD
--
Light travels faster than sound this is why some people appear bright until you hear them

Re: 18650 batteries for QCX

Daniel Sloss
 

I’ve learned that 18650 batteries come in both Li-Ion and LiFePo4 models and are slightly different sizes (LP4 batteries are a few mils longer) and also different voltages. For example, LiFePO4 are 3.2V each, at least the ones that I bought through Jaycar. Charging profiles are also different. The good thing about standards is that there are so many of them. Forearmed and forewarned.. Dan VK2NAD

Re: U3S pin ID?

Mike Berg
 

I connects power to the transmitter power amp from the +5v rail.

It gives the option of using a separate, higher voltage at the PA, assuming I read the instructions correctly.

U3S pin ID?

John
 

Just to the left of C1 are 4 post holes.What are the functions of these connections? I see in the assembly instructions that there is a bridge connection for the center pair but I have not found a description in the same instructions. Can anyone enlighten me?
--
Pura Vida

John W Clark
73
TI4JWC   TI4/N0URE  N0URE

Re: 18650 batteries for QCX

Daniel Sloss
 

I’ve learned that 18650 batteries come in both Li-Ion and LiFePo4 models and are slightly different sizes (LP4 batteries are a few mils longer) and also different voltages. For example, LiFePO4 are 3.2V each, at least the ones that I bought through Jaycar. Charging profiles are also different. The good thing about standards is that there are so many of them. Forearmed and forewarned.. Dan VK2NAD

Re: 18650 batteries for QCX

HF
 

Hi Steve,
I also used 4 18650 cells for my QCX.  They're mounted to a piece of acrylic under the QCX, making a compact assembly.  I also included a tiny voltmeter along with a toggle switch so that it indicates voltage only when I want to spend the 30 mA needed to light it up.  There's a 1N4000 series diode in series with the batteries to drop a little bit of voltage because they can charge up to 4.2 V each which gives a voltage higher than the 16.0 V which is the maximum voltage one of the chips in the QCX (I forget which one) can tolerate.  Another switch enables me to short out the diode after the first several minutes of operation during which the voltage per cell drops to 4.0V.  It turns out that the run time is longer than I need; if there's a next time, I'll use the same circuit with 14050 batteries to reduce the assembly's mass.
I also charge the cells individually.
Halden VE7UTS

Re: 18650 batteries for QCX

Jim W8JD <jimd2002@...>
 

Here is a picture of my rig and yes there there are 4 18650s in there, 2500 mah Panasonic's.  One is hidden stacked under the BMS (Battery Management System) board.  I built this into a Neat-gear router case.  This works awesome and averages just under 16v which nets 4.9 watts from my QCX-40.  I ran it for 24 hours on the first test "mostly receive" and the 18650s just sat at roughly 15.6v as measured by the QCX built in test equipment, (a nice characteristic of lithium technology).  They have a very flat discharge curve until depleted, then fall off rapidly. The BMS I used does not seem to "balance charge".  By that I mean as soon at one cell reaches 4.2v (max charge), the entire charger shuts down so the other three batteries may not reach max charge.  For that reason, I don't recommend it.  Since It does do a nice job of  protecting against over discharge though so I am going to roll with it and I have a hobby balance charger to keep it in shape.  You can find dozens of BMS boards on Amazon and eBay but the specs can be sketchy.   Lithium's are great but they cannot be overcharged or undercharged so a BMS is almost essential.  All lithium batteries in consumer equipment use some sort of BMS and that's good news because that makes them very affordable.  I mean less that 10 bucks for a 3s or 4s charger, (3s and 4s meaning 3 cells or 4 cells in series).  

The 18650 cells are normally "lithium cobalt oxide" technology (LCO) "3.6v nominal" as opposed to "lithium iorn phospate (LiFePO4 or LFP)" technology "3.2v nominal" which are usually come in flat pouches and prism shapes, more for RC hobby use.  The reason I bring this up is because there are dedicated chargers for each technology and with 18650 you will want the 3.6v per cell BMS which actually charges to 4.2v at cutoff.  The LiFePO4 chargers are 3.2v per cell and typically cutoff at 3.65v.  

Sorry this my may be information overload but suffice it to say that most of the BMS boards you will find on eBay and Amazon are designed for the 18650s 3.6v per cell so you should be OK.  I have a lot of experience with both technologies in my camper and e-bikes so if you have questions I am happy to help.

Properly executed, these LIPOS are nothing short of awesome.  You can thank the vapers for making the 18650 (180mm x 650mm) format so popular otherwise they would be carrying around motorcycle batteries for their e-cigs..

Like your call W4JED

73

Jim Davis W8JD  

Re: 18650 batteries for QCX

Steve in Okinawa
 

They seem popular with the Vapers, too, who aren't so concerned with weight but don't want to be caught without a light.

Re: 18650 batteries for QCX

James Daldry W4JED
 

Hi, Stephen

10 volt low cutoff would probably be all right, but if the cells aren't matched, your 10 volts could be 3 three volt cells plus a 1 volt cell. By doing this several times and throwing away the over-discharged cells, you can come up with a matched set of cells. Or, more simply, buy a 4 cell "brain" on Ebay and charge the thing with a common 12 volt battery charger.

73

Jim W4JED


On 9/28/19 7:02 AM, Stephen Farthing G0XAR JO92ON97 wrote:
Greetings Gentlefolk, 

I’m making a 4 x 18650 battery pack for my QCX. According to the seller each cell is rated at 3400 mAH but we shall see. 
I’m planning to make a charger using four TC4065A charging modules fed by a 4 port USB charger rated at 1.5 amps per port. That should give enough headroom for the 500 milliamperes charge rate for the TC4065a. To avoid cross charging (where a cell at higher voltage charges one at a lower voltage) when charging the cells won’t be connected together. 

When the battery pack is connected to the QCX I intend to monitor the overall voltage of the cells rather than each cell. And also the temperature of the pack. This should allow me to cease operations before the voltage drops to the point that any of the cells is discharged to the point that it’s damaged. Professionals monitor each cell but that’s too complicated for me and besides, I’m an Amateur. 
If I must I will but if I can I want to avoid complexity and weight. 

Any comments? 

Thanks, 

Steve G0XAR

Re: QCX power

Dan Hughes
 

Thanks Charles.   I just picked up one of these on Amazon.   I’m thinking it should do the trick.  

73,
Dan




On Sat, Sep 28, 2019 at 4:37 PM -0400, "Charles Mims" <chmims@...> wrote:

I have two of these. They work well, with no RF noise.  They are American made and well supported.  True they are more expensive.

Charles


Re: QCX power

Charles Mims
 

I have two of these. They work well, with no RF noise.  They are American made and well supported.  True they are more expensive.

Charles