Date   

Re: v0.6.3 Correct LPF Coil Values

Pedro
 

Hi Ronald,
Thanks for the info.
I already made the coils and carefully checked the value.
You were right, I had to remove 1 to 3 turns on each coil, in the end thay stay as in picture.
Now I need to check each LPF with the VNA

Abraço
Pedro - CT1CAH


Re

Dave
 

Thanks for the info!

Dave
KC3GPM
Sent using Zoho Mail


Re: v6.3 pa power adjust

Carl Horvath Jr
 

Kevin,

 

Send me an email helichuck at frontier.com

 

From: mcHF@groups.io <mcHF@groups.io> On Behalf Of Kevin
Sent: Wednesday, July 08, 2020 5:28 PM
To: mcHF@groups.io
Subject: [mcHF] v6.3 pa power adjust

 

I'm following the pa power calibration instructions at https://github.com/df8oe/UHSDR/wiki/Adjustment-and-Configuration-Manual .  I get 500ma with the pa bias at 0 and about 998ma with it set all the way up to 115.  The meter isn't the greatest and I'm running it on a 10A scale, so I'm assuming "close" to 500ma rise in current draw is good enough?
Which brings me to the problem.  I'm trying to set the TX RF POWER ADJUSTMENT.  I've tried multiple bands and full settings, but I don't seem to get any output.  I can't even get anything to show on the rf power meter, even if I change the reverse setting on it.
What can I test or do to get some power out?

Kevin
W9KH


Re: Source for buttons

Jim Mcilroy
 

Hi

I used these.

Mouser  101-0364-EV

They are a little taller than the one supplied in some kits but that worked better with the case that I had.

Jim  G4EQX

On 09/07/2020 18:09, Dave via groups.io wrote:

Hello,
I’m looking to replace some of the pushbutton switches on the UI board. I’ve looked at DigiKey, Mouser and Avnet with no luck so far on SMD switches.
Can anyone help?

Thanks,
Dave  KC3GPM
Sent using Zoho Mail


Source for buttons

Dave
 


Hello,
I’m looking to replace some of the pushbutton switches on the UI board. I’ve looked at DigiKey, Mouser and Avnet with no luck so far on SMD switches.
Can anyone help?

Thanks,
Dave  KC3GPM
Sent using Zoho Mail


Re: v0.6.3 Correct LPF Coil Values

Ron De Silva
 
Edited

Hi Pedro

I just finished ny second vsn63.

I was much more careful in the LPF this time.

I found the values of inductance on the coil winding help sheet to be correct.

But,the TURNS on my toroids came out closer by using the smaller  number of turns shown in the schematic  to obtain those inductance values.

Also,I had a NANO VNA to use in checking the coils and the bandpass of the filter.

I found that the actual turns needed for L16,20,24
and L15,19,21 were 2 to 3 turns less than the coil winding informatiom sheet


I'm.not sure if the toroid mixes are a bit different than the original cores.

But the stated inductance values on the coil winding info sheet are pretty close, if you have a way to measure the inductance. 

But sweeping the filters is the best.

On my first MCHF I only had 3 watts on 10 m.

On this one with carefully sweeping and adjusting the LPF, I have a very clean 7 watts now.

Boa sorte!



Ronáld
CU8/NU6F


v0.6.3 Correct LPF Coil Values

Pedro
 

Hi all
I'm building a 0.6.3 and I became confused with the values of some LPF coils, as in document
"MCHF Torroids uH values.pdf" the values for this coils are:
L20 11T 0.51uH
L16, L24 10T 0.44uH
L19 15T 0.90uH
L15, L23 14T 0.77uH
 
But on Schematics and at document “LPF Torroid winding guide.pdf” the values are:
L20 09T 0.32uH
L16, L24 08T 0.26uH
L19 14T 0.78uH
L15, L23 12T 0.58uH
I believe this last values are the correct ones, can someone confirm this?
Still regarding the LPF coils: shouldn’t all this 6 coils use T37-6 Toroids?
I see that on some images….
 
Thanks in advance for the help
Regards
Pedro
CT1CAH


Re: Winding T2/T3 toroids

Pedro
 

Hi Dave
I'm building a v0.6.3 too
Here is how I assembly T2 and T3, I try to get 90º between them but thiis the the best I got.
I hope it helps.

Regards
Pedro
CT1CAH


v6.3 pa power adjust

Kevin
 

I'm following the pa power calibration instructions at https://github.com/df8oe/UHSDR/wiki/Adjustment-and-Configuration-Manual .  I get 500ma with the pa bias at 0 and about 998ma with it set all the way up to 115.  The meter isn't the greatest and I'm running it on a 10A scale, so I'm assuming "close" to 500ma rise in current draw is good enough?
Which brings me to the problem.  I'm trying to set the TX RF POWER ADJUSTMENT.  I've tried multiple bands and full settings, but I don't seem to get any output.  I can't even get anything to show on the rf power meter, even if I change the reverse setting on it.
What can I test or do to get some power out?

Kevin
W9KH


Re: Simple hardware modifications for better the 50db rejection of the Tx carrier Leakage and out-of-band signals

Team-SIM SIM-Mode
 

Hi All

I purpose to test an added Led diode in serial with 3.4 V for lower power supply voltage of the Potatos devider PO74G74A  U11 (1.9 v instead of 3.4 volt as showen on the modified drawing below), knowing that it's showen in datasheet that potatos can run normaly down to 1.65 volt power supply ,  it may  help to have as near as possible to the 50% duty cycle of the I/Q Clock signals and then may involve less distorsions  on Tx out bands and less spurious signals on Rx Mixer results .  i have not tested yet , any hardware tester will be appreciated ...

(Sorry,  i mean R51 , R52, R71 and R72  100 Ohm resistors to be replaced by a 0 Ohm jumper in add of  R22, R23, R24 & R25 ) 

73's  Nizar  


Simple hardware modifications for better the 50db rejection of the Tx carrier Leakage and out-of-band signals

Team-SIM SIM-Mode
 

Hi All 

I experimented a very simple hardware modifications for a very good rejection of Tx LO carrier leakage and out of band signals , more then 50db rejection was obtained what is very nice value for a simple hardware designe as mchf kits (30db rejection only originally designe),  so only 80 mvpp LO leakage was measured on 50 ohm load  by a scope during Txing without any signal modulation, in addition to that the harmonic distorsions out of band signals  was also reduced around 50db rejection on the spectrum analyser what is very nice too. 

1) Add many Bypass capacitors > 1 uf  around Tx-Mixer  (see photo  attached below) with  a very short wire and a Bypass capacitors  between  PIN8  and Pin 16 of U17  Mixer circuit ( the shorten bypass circuit).

2) add two or three Baypass capacitors (10 uf , 4.7 uf and 1 uf) between the middle point of T4  transformer and Pin8 of U17.


3) Replace the 100 Ohm  R22, R23, R24 , R25 by a 0 Ohm jumper (I has the potatos 7474 with 3.3V ),
 
4) Add  many  Bypass capacitors for the Potatos  devider  7474 U11 as shorten as possible .

5) Remove the C107a and C108a capacitors of the Tx Quad preamplifier.

Really very simple to acheive and the result is there. just need some minor hardware works.

it's intended that the  (-24 Khz)  image rejection was already correctly rejected by firmware Tx adjustements on the menu. 

Good Luck   73's  Nizar 


Re: Rx mixer DC measurements

Mike K0JTA
 

AMEN to this, Roeland! Well done. 

This same battle (Friendly, I must stress!) has also been going on in the RS-918 user group for years.  Your very generous action of sending him a USB memory-stick with even return postage is supremely helpful, yet even this was turned down, apparently.  (!!)   Is it time for him to be removed from both user groups..??  I am ready on my end...
--
Mike, K0JTA 
https://www.qrz.com/db/k0jta
https://groups.io/g/Visible-Cell-Phone/topics


Re: Rx mixer DC measurements

Roeland Jansen, PA3MET <roeland.jansen69@...>
 

Nizar,

some time ago you were asked to comply to GPL, do you remember? Even when giving enough space to upload your full source tree (diffs would have been fine too).
You dismissed all the options given including receiving an USB stick to put the sources on and return postage paid. 

Why do you think that someone would help you by measuring stuff for your comparisions?



Re: Rx mixer DC measurements

Team-SIM SIM-Mode
 

Hello All

I just replaced the U15 SN74CBT3253C Rx Mixer by the desoldered U2 BPF Multiplexer  SN74CBT3253C,  but voltage values and dissymetrie between I and Q channels are approximatly the same !!!!!  

helpe will be appreciated 

thanks  

73's   Nizar 


Re: Mic for mcHF V6.3

Patrick Gooden
 

Lucy,

If the mic connections haven't changed since the V6.0, the one that I am using is the tip-ring-ring-sleeve made for a Yaesu handheld (such as the FT-60 radio).And, you can buy it from Amazon online service.

Patrick K6PFG 


Re: Blank screen on power-up - update

Jim Mcilroy
 

Glad to hear it.

Enjoy the build.

Jim

On 05/07/2020 20:01, Dave via groups.io wrote:
Hello,
I just figured out what happened with my screen (insert closest wall to hit head upon). I was so nervous, I didn't hold the power button down long enough! Once I figured that out - by accident, it powered up and the button check passed for all buttons.

Thanks for the suggestions - on to the RF shield and case construction.

73,
Dave

KC3GPM

Sent using Zoho Mail




Re: Blank screen on power-up - update

Dave
 

Hello,
I just figured out what happened with my screen (insert closest wall to hit head upon). I was so nervous, I didn't hold the power button down long enough! Once I figured that out - by accident, it powered up and the button check passed for all buttons.

Thanks for the suggestions - on to the RF shield and case construction.

73,
Dave

KC3GPM

Sent using Zoho Mail




Re: Re

Carl Horvath Jr
 

On Sun, Jul 5, 2020 at 8:32 AM, Jim Mcilroy via groups.io
<gts53@...> wrote:

Hi Dave

Have a look here.

There is lots of other information too about mcHF

https://github.com/df8oe/UHSDR/wiki/Topics:-UHSDR:-SW-Installation-on-SDR


On 05/07/2020 12:13, Dave via groups.io wrote:
Hi Carl & Jim,
I thought it was already loaded when I purchased the kit. To answer your question, I don’t know what version is loaded.
Should I try a reload, and if so, what version? 
Sorry...software isn’t my strong suit when it comes to working with chips.

Dave
KC3GPM
Sent using Zoho Mail


Re: Re

Jim Mcilroy
 

Hi Dave

Have a look here.

There is lots of other information too about mcHF

https://github.com/df8oe/UHSDR/wiki/Topics:-UHSDR:-SW-Installation-on-SDR


On 05/07/2020 12:13, Dave via groups.io wrote:
Hi Carl & Jim,
I thought it was already loaded when I purchased the kit. To answer your question, I don’t know what version is loaded.
Should I try a reload, and if so, what version? 
Sorry...software isn’t my strong suit when it comes to working with chips.

Dave
KC3GPM
Sent using Zoho Mail


Re

Dave
 

Hi Carl & Jim,
I thought it was already loaded when I purchased the kit. To answer your question, I don’t know what version is loaded.
Should I try a reload, and if so, what version? 
Sorry...software isn’t my strong suit when it comes to working with chips.

Dave
KC3GPM
Sent using Zoho Mail

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