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QDX First Power Up Help

Bill
 

I just finished assembly of my QDX Rev. 2 and want to power it up to test it. I wired the transformer for 12v, but thought I would hook up a 9v alkaline battery to do the initial power up to avoid burning anything out if I made a mistake.
I have another 12v 3amp power supply that I plan to use if everything checks out OK. I also have a regulator which could drop that voltage to 9v if necessary.
Do you think using the battery first is a good way to go?
Any other thoughts to test it on first power up?
Thanks.

 


Re: If a U4B was to be used as a garden dipole

tony.volpe.1951@...
 

Thanks Dave. I will check it out.

I am hoping Hans will be putting his new U4B in his shop soon. I know he is very busy with meeting other sales requests though, so I can wait to set up my garden U4B project. I have already worked out the solar cells I will use and have a 4.2v cell phone battery that ought to work the thing. I am going to use a series diode to protect the little board from voltages above 5 volts in bright sunshine.


Re: TX and RX Frequency Difference #40m

Ronald Taylor
 

(Measured F / Displayed F) X (Current Reference F) = New Ref F

(7116000 / 7115200) X (27,004,000) = 27,007,036.2

Glad it worked. 73… Ron

On Mon, Feb 14, 2022 at 15:25 Ernie Bailey - N2DGQ <ebrcdddcdc@...> wrote:
I have just completed my QCX Mini Build for 40M.  The RX and TX Freq seem to be off by about 80Hz.  For example, I TX on 7.115.20 and RBN says I'm at 7116.00.  The delta is consistent no matter where I go on the band.  Do I need to tweak the reference frequency or is this normal operation for the QCX Mini's?

Thank you in advance for your helpful feedback.  


Re: New QDX up and running, but we need to talk about FT8 and QRP

Mel Snyder
 

This sums up why CW is still the eternal mode. 

Mel - W3PYF


On Feb 15, 2022, at 06:44, R. Tyson via groups.io <tysons2@...> wrote:

On Mon, Feb 14, 2022 at 07:54 PM, Paulo CT wrote:
However, running QRP on the actual FT8 channels is an exercise in frustation. Long have gonne the days that a 25w signal was considered QRO.
That's why I don't use FT8.  It was supposed to be a way of sending/receiving weak signals. Now it's just turned into computers talking to each other and stupid amounts of RF power being used. What is the challenge/interest in running high power so your computer can conduct a very brief and minimal QSO on your behalf  ( I don't mean you personally    >:-)   )

Reg               G4NFR


Re: New QDX up and running, but we need to talk about FT8 and QRP

R. Tyson
 

On Mon, Feb 14, 2022 at 07:54 PM, Paulo CT wrote:
However, running QRP on the actual FT8 channels is an exercise in frustation. Long have gonne the days that a 25w signal was considered QRO.
That's why I don't use FT8.  It was supposed to be a way of sending/receiving weak signals. Now it's just turned into computers talking to each other and stupid amounts of RF power being used. What is the challenge/interest in running high power so your computer can conduct a very brief and minimal QSO on your behalf  ( I don't mean you personally    >:-)   )

Reg               G4NFR


Re: New QDX up and running, but we need to talk about FT8 and QRP

Vojislav [YU4HAK]
 

Yes it is extremely annoying. In my opinion, only thing to do is to spread the word, and endlessly argue with QRO folks about what "weak signal mode" actually means. That it is ok to use 1kw when shooting at the moon, but not really on HF.


Use FT1XD GPS as input for QCX

Jan Brink
 

Anyone has tried to use Yaesu FT1DX GPS output for QCX (WSPR operation) ? Cable CT-170 should fit ?


Re: Cheap HB dummy load

tmmlrd
 

I don't know the device you are speaking about.  Could someone please post a ref or link? I surfed the web with "cheap HB dummy load" but didn't find an exact match... thanks
73


Re: Just saying thanks

Alexander Korotkevich
 

I can tell you for sure, that at least me used the QCX mini order to stimulate myself to finish the Koch lessons. So it really works this way!

73!

de Alex, W5KAO/RV3DFL.


Re: If a U4B was to be used as a garden dipole

VE3KCL
 

Attached is an interesting site for wspr spot tracking.  https://wspr.live/gui/d/LmMd4oUiz/station-activity?var-sign=VA3UAL&var-mode=tx&var-not_mode=rx&var-band=10&var-band=14&var-band=28&from=now-30d&to=now&orgId=1
It is set up for the dipole, but you can enter your own call (or two calls) and use the many wonderful features to visualize wspr transmission and reception.
The U4B fan dipole's Basic program looks at the battery voltage and transmits from 2 to 3 times an hour depending on the voltage, and only one time an hour, if the solar voltage is low.
The above Grafana site is quite interesting and fun to use. By changing the variables, you can visualize different things relating to your wspr spots ,your rx antenna profile or other data.
In Canada the month of December is a poor source of sunshine, so the solar dipole would not transmit 24/7 and would go to sleep early and wait till about 10 am local when there was enough winter light to transmit. Looking at the recent days spots graph, the solar cells have been able to charge the lipo battery to get 3 transmissions per hour, so the number of spots have come up and hopefully this frequency will continue through summer to late fall.
73 Dave VE3KCL VA3UAL 


Re: Second Best location for an antenna tuner #antenna #tune

Jim Allyn - N7JA
 

I used random length wire antennas for several decades before there was such a thing as an autotuner (or at least, I was unaware of their existence if they did exist).  So, the manual tuner was always right at the rig where I could tune as needed.  The best place for a tuner is wherever it allows you to get on the air.  Easy peasy.  At the other end of the scale, the impedance of an antenna will vary with frequency, therefore the SWR will vary with frequency.  The loss in a transmission line will vary with frequency and will vary somewhat depending upon the SWR present on the line.  Then you have the losses in the balun, which will vary with frequency and with the impedances presented to it at either end.  Of course the losses in the tuner will also depend upon frequency and SWR presented to it.  So, if you really want to know the best place for your tuner, you need to know the impedance of the antenna at several frequencies in each band of interest, the loss in the transmission lines at every frequency and SWR that will be presented to it, and the loss of the balun and the tuner at every frequency and SWR (and power level) presented to it.  You could probably do the measurements on all that in a month or two.  Then you could write a program to calculate which combination of transmission lines, balun location, and tuner location and settings results in the best efficiency.  If that sounds like a lot of fun to you, then that's what you should do.  Otherwise, put the balun and the tuner wherever they are most convenient, and get on the air and have fun.  And maybe now and then, when you feel like it, change something in your system and see if it works any better.  Or don't.

But to answer your question, yes you are presenting a reasonable degree of understanding, as far as it goes.  Now go get on the air.


Re: TX and RX Frequency Difference #40m

Ernie Bailey - N2DGQ
 

Ron and George,

Thanks for you for thoughtful input.  I do not have a GPS.  Setting the ref freq. at 27,0047,036 worked.  If I may ask, what is the math you used to calculate the new ref. freq.?  


Re: TX and RX Frequency Difference #40m

Ronald Taylor
 

Hi Ernie. If you have the 27 MHz reference crystal in there, and if you don't have a GPS, try setting your reference frequency to 27,007,036 and see if that helps.... You are actually 800 Hz off per the numbers you mentioned. Good luck ... Ron


On Mon, Feb 14, 2022 at 4:02 PM George Korper <georgekorper@...> wrote:
 
Hi,
Calibration by GPS will correct this. Did you purchase the QLG2 SE GPS accessory. I can't help you with manual calibration. I'm sure other posts will follow. 
The GPS option is critical for Beacon mode and WSPR. It turns the Mini into a real powerhouse, and each software revision has made it better! 


Re: TX and RX Frequency Difference #40m

George Korper
 

 
Hi,
Calibration by GPS will correct this. Did you purchase the QLG2 SE GPS accessory. I can't help you with manual calibration. I'm sure other posts will follow. 
The GPS option is critical for Beacon mode and WSPR. It turns the Mini into a real powerhouse, and each software revision has made it better! 


TX and RX Frequency Difference #40m

Ernie Bailey - N2DGQ
 

I have just completed my QCX Mini Build for 40M.  The RX and TX Freq seem to be off by about 80Hz.  For example, I TX on 7.115.20 and RBN says I'm at 7116.00.  The delta is consistent no matter where I go on the band.  Do I need to tweak the reference frequency or is this normal operation for the QCX Mini's?

Thank you in advance for your helpful feedback.  


Re: New QDX up and running, but we need to talk about FT8 and QRP

Mike Besemer - WM4B
 

On Mon, Feb 14, 2022 at 02:54 PM, Paulo CT wrote:
Should we start talking about a new spot for digital QRP ops?
No... the QRO guys will just take that over too.

Mike
WM4B


Re: New QDX up and running, but we need to talk about FT8 and QRP

N3MNT
 

I agree completely, however in today's ego driven world I am not sure this is fixable.  For me the challenge/thrill is miles/watt and no simply miles. 


Re: QCX-Mini 20m build complete - couple of issues #20m

@DL2COM
 

Thank you everyone for your comments which have been very helpful! For now I will assume that my QCX is working as it should (no mistakes building it) and I will do my best to avoid the RF issues. 

vy 73 de Leo (DL2COM)


Re: Added Folder /Cheap HB dummy load #file-notice

Pat - N0SHU
 

I've got an idea for an inexpensive dummy load:  


Re: 160m WSPR worked great for me on 1.09 firmware overnight

 

Oh dear, I didn't want to cause trouble :-(

Yeah, "Save State", that works; my troubled mind can handle that.

No, don't change a thing unless you need the space: it ain't broke, so you shouldn't feel the need to fix it!
--
Julian, N4JO.

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