UpTech Store Efficiency Kit Lo

Post Reply
thewanderer
 

Posts: 3
Joined: 15 Oct 2022, 03:19

UpTech Store Efficiency Kit Lo

Post by thewanderer »

Hello all,

I recently purchased the kit from UpTech store through aliexpress. I assembled the boards as per "(tr)uSDX #2 - complete assembly Instructions" video and the schematic. I have flashed both the bootloader and the firmware (stable) onto the board following the steps on the website. I've setup the features in the menu as per DL2MAN's video "(tr)uSDX #4 - How to use it" and I've followed the "(tr)uSDX - Tuning the RF Section for Output Power and Efficiency" utilising a nanovna and a 50ohm dummy load.

My first readings after aligning the second harmonic (running 12V/1A PSU) for each band was:

Code: Select all

Name, Band (M), Freq (Mhz), Power (w), Efficiency (%)
L1, 20, 14.06, 3.19, 69.37
L2,30, 10.106,4.73, 73.75
L3, 40, 7.03, 3.38, 73.6
L4, 60, 5.351.5, 3.72, 72.75
L5, 80, 3.56, 6.35, 74.34
After removing one turn form L12, L31, L42 and realignment with nanovna. I was able to get this. (I intend to add another turn to L51 to lower the power but I haven't done that yet.)

Code: Select all

Name, Band (M), Freq (Mhz), Power (w), Efficiency (%)
L1, 20, 14.06, 4.3, 70
L2,30, 10.106,4.73, 73.75
L3, 40, 7.03, 4.7, 74
L4, 60, 5.351.5, 4.99, 74
L5, 80, 3.56, 6.35, 74.34
After a number of times going back with nanovna and adjusting coils I wasn't able to get above 74% efficiency. I read through the forums and I noticed some people mentioned lowering windings on L15 from 22 to 19 improved efficiency. There was also a link to a video by DL2MAN talking about the wire diameter originally being 0.4mm and the kit now had 0.54. Therefore 19 windings should be fine. So I got out my calipers and measured the wire which turned out to be 0.5mm. I lowered the windings to 19 and remeasured. I noticed a slight increase in power but no change in efficiency.

Right now i'm unable to get above 74% efficiency. Does anyone have any recommendations on what to try?

Update: I haven't tried the "Suggested Mod of T2 for Efficiency Improvements" I just followed the windings as detailed in the schematic/iBOM. I'll give that a shot but if anyone has anything else I should look at , please let me know.
dl6sez
 

Posts: 399
Joined: 30 Dec 2021, 22:54

Re: UpTech Store Efficiency Kit Lo

Post by dl6sez »

Hello OM,

your (tr)uSDX is really bad OM!

No, sorry your tx efficiency seems to be good....
Do you have really measured rx current and substracted from measured tx current? Than calculated Pin
Have you done measurements of rf voltage at a dummyload and calculated the real rf output power?
Have you than adjusted R shunt in the menue to get readings in range of your real calculated efficiency?

I think you are hunting mice... :)

73 de Chris
Chris DL6SEZ, JN48XL near Ulm, Southern Germany
DL2MAN
 

Posts: 706
Joined: 30 Dec 2021, 19:18
Contact:

Re: UpTech Store Efficiency Kit Lo

Post by DL2MAN »

dl6sez wrote: 27 Nov 2022, 21:22 your (tr)uSDX is really bad OM!
You made my day !
dl6sez wrote: 27 Nov 2022, 21:22 I think you are hunting mice... :)

73 de Chris
Exactly ! Calibrate your internal measurements before judging your rig s efficiency based on that.

73 Manuel; DL2MAN
thewanderer
 

Posts: 3
Joined: 15 Oct 2022, 03:19

Re: UpTech Store Efficiency Kit Lo

Post by thewanderer »

I'm waiting on a oscilloscope but I've done some measurements using the QRP-labs dummy load and a DVM. Obviously it's not as accurate, but it's what I can use ATM.

Outout power = vpeak^2/100.
Pin= Input Voltage*(TX-RX)
Eff = Pout/Pin*100

Here are my measurements

Name, Band (M), Freq (MHZ), Input Voltage (V), Input Current RX (A), Input Current TX (A), Output Power (W), Eff (%), Voltage Peak (V),

L1, 20, 14.06, 11.98, 0.076, 0.509, 4.301, 5.19, 82.9, 20.74
L2, 30, 10.106, 11.98, 0.074, 0.55, 4.298, 5.702, 75.36, 20.73
L3, 40, 7.03, 11.98, 0.072, 0.56, 4.297, 5.846, 73.5, 20.74
L4, 60, 5.351.5, 11.98, 0.07, 0.55 4.301, 5.75, 74.803, 20.74
L5, 80, 3.56, 11.98, 0.071, 0.6, 5.626, 6.337, 88.78, 23.72

Edit: Just reading through the posts again. I wasn't assuming anything wrong with the kit, I was assuming I had made some mistakes with the build and was looking for suggestions for debugging it. I'm very appreciative of the work of Guido and Manuel in making this project.
thewanderer
 

Posts: 3
Joined: 15 Oct 2022, 03:19

Re: UpTech Store Efficiency Kit Lo

Post by thewanderer »

Hello all,

Okay got the CRO. Measurements are now above 80% eff for all bands. Just need to adjust the r-shunt to match.

Thanks for the advice.
Post Reply

Users browsing this forum: Bing [Bot] and 1 guest