Date   

Re: QRP Guys are OK

Braden Glett
 

I just ordered a QRP trap antenna with built-in tuner and SWR indicator from them, yesterday. I understand that they can be a little slow but they are performing a great service to the QRP Ham community for little reward. God bless them all. 


Re: New 20 Meter QCX failure

James Daldry W4JED
 

Hi, Floyd

Pin 8 of IC3 is connected by R43 to the antenna jack. It is the source of the signal you use to align the bandpass filter and the sideband filter. Being that it is shorted to ground would indicate either a shorted IC or a wire clipping, solder whisker, etc shorting the pin to ground. If it is a shorted IC, it could either be an early-life failure (the reason for 90 day warranties) or something overloaded / overvoltaged the IC and blew it. In the first case replacing the IC will fix the set. In the second case replacing the IC wil result in failure of the replacement.

Looking at the schematic we have one connection to IC3 that appears capable of damaging the IC - the one to Q1 thru Q3, pin 3 of IC3. Since the IC is shorted it needs to be removed before any further testing can be done. This can be done with either (a) solder wick, extra solder, patience, and care or (b) a desoldering tool like the Velleman desoldering pencil that's $10.45 on Amazon. Once you have the IC out, check the resistance from the pin 3 hole of the board to ground and to the collector of Q6. If either reading is less than infinite you need to replace Q1, Q2, Q3, and Q6 as well as IC3. Since you had low power before the failure, you might want to replace C25 and 26 while you're at it.

The 74ACT00N is identical to the 74ACT00NG which Arrow has 24000 of at 18 cents each, free overnight shipping.

Jim W4JED

On 2/4/19 4:43 PM, Floyd Abrames wrote:
My recently finished QCX 20 failed after maybe 30 minutes of use.  The only problem at that time was the common one of low power.  I was studying the testing procedures when the lcd display went blank.  I happened to touch the 7805 voltage regulator and it was extremely hot.  I took power off immediately.  No smoke or burned smell. I put a ampmeter in line and added power just long enough to get a reading which was 600ma.  Not wanting to burn up the 7805 I did some checking power off.  I found resistance from 5volt supply to ground to be 14 ohms and pin 8 of IC3 was 1 ohm to ground.  Pin 8 has a short lead to R43 {120K).  I looks to me that IC3 has failed internally. IC2 controls the lcd so it may have died.  The lcd was checked on an arduino and is ok.  I hate to change IC3 but looks like the best starting place.
I can find no supplier for the 74ACT00N.  Any help?  Any disagreement with my logic?  
Thanks for any help

Floyd AA0GU


Re: QCX kit -- Use of IC Sockets

Steve Nichols
 

Hi Al,

I used sockets on mine, mainly because I had to cut out one of the chips after a failure and didn't want to have to do that again!

I haven't noticed any extra noise etc. I think that Hans was concerned that sockets could just introduce another potential source of bad connections.

Steve G0KYA


Re: Power supply for clock kit #clock #supply

Art N4EZZ
 

I have used a power supply obtained from Jameco as well but a slightly
different one.

Their part number is #1919043. I went for something hard wired to reduce
the potential for errors in the future. Lots of choices.

Have fun with it, I am waiting on my next kit an Ultimate3S.

Art N4EZZ <n4ezz@...>
GnuPG key ID 0x6712DD0E
=============================
"Wink at small faults; remember thou hast great ones."
BENJAMIN FRANKLIN, Poor Richard's Almanack, 1738

On 2/5/19 6:46 AM, Curt M. wrote:
I've built two clock kits and I'm using a Jameco 1953612 to power each of them.  One of them has been on 24/7 since I built it.

If you give Jameco your email address I think they will give you $10 off your order.

https://www.jameco.com/z/DDU050100M2270-AC-DC-POWER-SUPPLY-WALL-ADAPTER-TRANSFORMER-SINGLE-OUT-5V-1A-5W_1953612.html




Re: Power supply for clock kit #clock #supply

Roger Hill
 

Hi Dave

Don't chop the plug off. Get yourself a suitable chassis-mounted power socket to match the plug. Wire that to the clock. Then you can use the power supply on more than one item of kit.

I used a raspberry pi supply rated at 2.5 amps..and fitted my own plug to match the socket I had.

Roger

Roger


On 5 February 2019 13:32:31 GMT+00:00, "Dave Capstick via Groups.Io" <cappers1001@...> wrote:
Hi All,
first time post and a relative newbie to construction.  I've recently purchased 3 kits to get me going, these are:
- clock kit
- QLG1 GPS kit
- QCX80

I've eventually got round to building the first one of these (clock kit) and i was wondering what other people have used as a power supply and how they've connected this up to the clock power pins?  The manual states that you should use a well regulated power supply - what's considered well regulated? Also, most of these end up with a barrel type socket at the end, do you simply cut this off and solder on a connection pin, like you have with jumper cables?  How about a 5v battery?  I have one that i use to power a raspberry pi, but that has a usb socket - so would i have to split the cable and again connect the ends up to a jumper cable.
I'm sure this is a really simple job, but i just need to clarify what the best solution might be

Thanks for your help

Dave
M0IKT

--
Sent from my Android device with K-9 Mail. Please excuse my brevity.


Re: IMHO a great YouTube video on understanding toroidal cores

 

W0QE, Larry's videos are very good. He has a firm understanding of RF and SimSmith and he presents the info in an understandable way.
--
73
NE5U

Mike


Re: Power supply for clock kit #clock #supply

Curt M.
 

I've built two clock kits and I'm using a Jameco 1953612 to power each of them.  One of them has been on 24/7 since I built it.

If you give Jameco your email address I think they will give you $10 off your order.

https://www.jameco.com/z/DDU050100M2270-AC-DC-POWER-SUPPLY-WALL-ADAPTER-TRANSFORMER-SINGLE-OUT-5V-1A-5W_1953612.html 


Power supply for clock kit #clock #supply

Dave Capstick
 

Hi All,
first time post and a relative newbie to construction.  I've recently purchased 3 kits to get me going, these are:
- clock kit
- QLG1 GPS kit
- QCX80

I've eventually got round to building the first one of these (clock kit) and i was wondering what other people have used as a power supply and how they've connected this up to the clock power pins?  The manual states that you should use a well regulated power supply - what's considered well regulated? Also, most of these end up with a barrel type socket at the end, do you simply cut this off and solder on a connection pin, like you have with jumper cables?  How about a 5v battery?  I have one that i use to power a raspberry pi, but that has a usb socket - so would i have to split the cable and again connect the ends up to a jumper cable.
I'm sure this is a really simple job, but i just need to clarify what the best solution might be

Thanks for your help

Dave
M0IKT


Re: 2 x 20m WSPR/QRSS balloons launched back to back

Jim .....
 

Now just need some WSPR spots for telemetry !



Re: 2 x 20m WSPR/QRSS balloons launched back to back

Jim .....
 

rellekevets - Yes,you can go here and see details of payloads and balloons.Everything you need is there -
http://radio-signals.com/forum/
There is a lot there to look over and get familiar with designs.
Drop me an email anytime...QRZ.com email good.
WD4AH once again is hearing BOTH signals this morning...just amazing and one heck of a receiver he has there!!
Thank you Al...you made my day.
Jim,N2NXZ


Re: 2 x 20m WSPR/QRSS balloons launched back to back

Steve AE8AT
 

Neat!

Do you have a description of the balloons and payloads posted somewhere?  I'm preparing a launch and would be interested in what balloon, gas, battery, etc.


Re: New QCX 20 - looking for sanity check on transmit power please #qcx

David Wilcox
 

Thanks everyone about the infrared thermometer info.  Somehow I thought the HF one would not be accurate enough but now will pick one up when the next sale flyer comes.

Dave K8WPE since 1960.

On Feb 4, 2019, at 10:35 AM, jjpurdum via Groups.Io <jjpurdum@...> wrote:

Hi Jerry:

One of my Christmas presents was the infrared thermometer from HF. It works well (e.g., I now know I like my coffee at 127.5 degrees!) and I use it often to check heat sink and component temperatures. It costs about $20, but I think it's worth it. You may find it a little more "directional" than the other one. I don't see the model I got listed now, but it looks similar to:


Jack, W8TEE



On Monday, February 4, 2019, 10:25:16 AM EST, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:


I find my Harbor Freight item 93983 to be well worth $12.
And sometimes it's on sale.
  https://www.harborfreight.com/non-contact-pocket-thermometer-93983.html

I suppose if you wanted to verify it for ceramic caps, you could heat the cap
with a soldering iron until drops of water start to boil away, then check if it's close to 100 C.

A real infrared camera would be fun, but out of my budget.
Each pixel can tell you the temperature of the object
in that part of the view to within a degree or so.
And if you get the right one, you have an excellent excuse to play with liquid nitrogen.
 
The hobby shops sell some cheap near-infrared cameras, basically cell phone cameras
with glass lenses, but the IR filter removed, I'm curious if anybody has had any luck
using one of those for finding PC board hot spots.

Jerry, KE7ER


On Mon, Feb 4, 2019 at 03:14 AM, geoff M0ORE wrote:

If looking for a temperature rise, the accuracy is not that important. An accurate IR thermometer is only as good as setting the Emissivity  for the material being checked. This has a direct bearing on the temperature being measured.

If you can find a value for ceramic capacitors, please let me know.

A better indicator would be a thermal camera to look for hot spots.

Geoff

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Re: Replacement part for IC4 #fst3253

Alan G4ZFQ
 

While not related to the chip in question, components can and do fail for no reason.
Andy,

I realise this particular one under discussion was damaged by some mishap.

I have a QLG1 which was happily running for weeks, Problem was traced to the IC, there was a pulsed input but a constant output instead of pulsing. New chip ordered from a reputable supplier, fitted into a socket and GPS is now happy again.
As Hans has said, can you be absolutely sure another fault was not rectified by the disturbance of the replacement? Did you test the IC after removal, or was it damaged by that unknown fault? It might just take a solder or wire remnant to short something before it drops never to be found. It sounds unlikely but much of our complex modern electronics run for years without failure.
Yes a few components do die but on the other hand I am amazed just how robust many are. ICs getting really hot due to being the wrong way round, complex SM ICs removed/replaced a number of times still working apparently normally.

73 Alan G4ZFQ


Re: Replacement part for IC4 #fst3253

M0RON
 

While not related to the chip in question, components can and do fail for no reason. 
I have a QLG1 which was happily running for weeks, then I noticed that the red and green led's were permanently lit, green led should pulse, also no pulsing yellow led.
Problem was traced to the IC, there was a pulsed input but a constant output instead of pulsing. New chip ordered from a reputable supplier, fitted into a socket and GPS is now happy again. 
No reason for the failure, it just did. Maybe it was slightly out of tolerance when manufactured or poor materials. But I do agree, it is rare for good chips to fail. 
Andy.
--
The universe is made up of Protons, Neutrons, Electrons but contains only one M0RON.


Re: New 20 Meter QCX failure

Alan G4ZFQ
 

Just wish I knew why the failures
Floyd

I'd be very careful with the repair.
Remove the damaged components.
Replace the regulator IC11.
Check for shorts on the 5V output.
Check you get 5V before replacing the ICs.
One component failure is just possible, two is very likely due to overvoltage or reversed polarity.

73 Alan G4ZFQ


Re: QCX-SSB: SSB with your QCX transceiver

Jerry Gaffke
 

I'd imagine a very abrupt change in frequency would not work.
But slewing at a reasonable rate between the two might.

And that "reasonable rate" may have to be slow enough that we spend
most of our time in the middle anyway.

Jerry


On Mon, Feb 4, 2019 at 07:33 PM, Jerry Gaffke wrote:
if we could get by with just two frequencies for the square wave.
One on the lower edge of the normal SSB passband, one on the upper edge.


Re: QCX-SSB: SSB with your QCX transceiver

Jerry Gaffke
 

> And a scope is far from the best tool to see frequency variation.

Not what I was looking for.
I was looking for an occasional ghost from a short or long clock pulse
when the output made the transition on small changes to
the si5351 output multisynth fractional divider.  Wasn't there.

Lots of folks using the si5351 in communications gear beyond the uBitx.
Including a bunch of stuff from Hans. 
Some of the Si53** docs suggest jitter when using multisynth output divides
within a factor of two of jitter when using integer divides, and I'm convinced
that's clean enough.
 
> Well you have to wonder ...

Indeed.  I had been thinking it was important to keep the frequency 
of the transmitted signal as close as possible to where it "should" be.
But if phase is all we really care about, perhaps it's ok to have the
square wave frequency push the edges of what is normally the passband.

I wonder ....  if we could get by with just two frequencies for the square wave.
One on the lower edge of the normal SSB passband, one on the upper edge.
Control the phase by adjusting the amount of time it spends at the low freq
vs the high freq.  My gut feeling is that it would not work well, but then
my gut has often been wrong about this EER stuff.  Would be an interesting
experiment, see what it does to audio quality, and to a spectrum analyzer display.
If it works well, imagine the guy at the far end, staring in disbelief at his waterfall.

Jerry, KE7ER



On Mon, Feb 4, 2019 at 06:30 PM, ajparent1/KB1GMX wrote:
And a scope is far from the best tool to see frequency variation.


Re: QCX-SSB: SSB with your QCX transceiver

ajparent1/KB1GMX
 

On Mon, Feb 4, 2019 at 10:48 AM, Jerry Gaffke wrote:
>>>Nobody's mentioned an issue with phase noise on the uBitx, and that uses output multisynth dividers.<<<

No body has looked and likely buried under the IMD.

>>>Abrupt small changes in frequency are probably ok, the clock pulse at the moment of transition
from the output multisynth divider is indistinguishable from its neighbors on a scope,
But if we are doing updates at only 8khz, those frequency changes could be large enough
to cause trouble.<<<<

Well you have to wonder does changing he frequency say 400hz (phase change) have more
effect than the the act of changing it 8000 times a second?  Both modulate the oscillator
by changing it.

And a scope is far from the best tool to see frequency variation.  If the setup is for an
eye pattern then you can see the eyes close (fill) when there is phase changes but even then 
I has to be fairly pronounced.

Allison


Re: QCX-SSB: SSB with your QCX transceiver

Jerry Gaffke
 

You're right, not much FP.

I've been looking at his older RPi code:
    http://pe1nnz.nl.eu.org/2013/05/direct-ssb-generation-on-pll.html

Jerry



On Mon, Feb 4, 2019 at 05:29 PM, ajparent1/KB1GMX wrote:
Pulled from the code,  The only floats are outside the TX loop for the display.  Everything is integer
and there is little reason for floats as they take a long time and offer precision that is not usable by
5351 or PWM.


QRP Guys are OK

Kadicha
 

My order, placed 11 January, arrived to my QTH, Australia, on 5 February.  Previous orders were also quite quick.
Dermy
VK1FDHA