Search found 54 matches

by va3rr
11 Aug 2022, 15:09
Forum: General Information
Topic: Use for extra toroids?
Replies: 4
Views: 783

Re: Use for extra toroids?

You can make an EFHW tuner with the powder core toroids, but you might want to stack 2 of them.

https://www.aa5tb.com/coupler2.html

Image
by va3rr
10 Jun 2022, 13:43
Forum: Troubleshooting
Topic: Suggested Mod of T2 for Efficiency Improvement
Replies: 24
Views: 5018

Re: Suggested Mod of T2 for Efficiency Improvement

Just wondering, was 2T/14T not viable for some reason? Just thinking that this turns count would (more) easily fit the core using 0.4mm wire. Robert - it looks like Owen Duffy did the maths on the 2T/14T and it checks out ok. He also has other blog articles about the Tr(u)SDX https://owenduffy.net/...
by va3rr
13 May 2022, 21:19
Forum: Troubleshooting
Topic: Suggested Mod of T2 for Efficiency Improvement
Replies: 24
Views: 5018

Re: Suggested Mod of T2 for Efficiency Improvement

Wonderful out-of-the box thinking! I would have suggested using a binocular core like a BN43-202, as it provides far more inductance with 7 turns than a FT37-43 does. But this allows us to continue to use our existing RF boards!

Well done!
by va3rr
04 May 2022, 12:11
Forum: General Information
Topic: Short Encoder
Replies: 6
Views: 751

Re: Short Encoder

Robert;

I purchased Uxcell short shaft encoders from Amazon that have the correct A/B line phases

https://www.amazon.ca/gp/product/B07R8G ... UTF8&psc=1

Which allows me to use a nice AL tuning knobs from Aliexpress...
by va3rr
27 Apr 2022, 13:05
Forum: Troubleshooting
Topic: Very low output power (0.1W)
Replies: 16
Views: 1807

Re: Very low output power (0.1W)

I also found it interesting that SWR coil is heating up, but there is practically 1:1 SWR as I used dummy load. T2 will heat up, because it's 7 turns are in shunt with the load. Fewer turns provides better sensitivity for QRP levels. Here's a good explanation from Owen Duffy: https://owenduffy.net/...
by va3rr
25 Apr 2022, 14:42
Forum: Troubleshooting
Topic: strange Amidon T37-2 toroids
Replies: 4
Views: 605

Re: strange Amidon T37-2 toroids

Joke aside: The Material is imported and it´s only pressed in China. Once again I´m happy, that we found a really good chinese supplier, that takes it seriously. 73 Manuel, DL2MAN This is a very interesting development. I wonder where they source their cores? I've measured what I think is a Caracol...
by va3rr
20 Apr 2022, 11:47
Forum: General Information
Topic: TOROID T1 T2
Replies: 14
Views: 1431

Re: TOROID T1 T2

You can use magnet wire for the single turn, as well. Some prefer different colours for transformer primary and secondary in case troubleshooting is required...
by va3rr
19 Apr 2022, 19:54
Forum: General Information
Topic: TOROID T1 T2
Replies: 14
Views: 1431

Re: TOROID T1 T2

Perhaps he's asking about extra insulation on the single turn? I wanted to add that the 7 turns should be wound counterclockwise, at least according to what I've read on the Kits and Parts website. https://www.kitsandparts.com/howtowindtoroidswithoutpain.php Here's a colour photo of T2, although it'...
by va3rr
15 Apr 2022, 18:10
Forum: Troubleshooting
Topic: (tr)uSDX power, efficiency and filter optimisation
Replies: 177
Views: 28603

Re: (tr)uSDX power, efficiency and filter optimisation

It appears Owen Duffy has been following the L15 discussion

https://owenduffy.net/blog/?p=24648#more-24648
by va3rr
12 Apr 2022, 16:41
Forum: Troubleshooting
Topic: PURCHASED FROM *Rxxxx* Technologies
Replies: 4
Views: 756

Re: PURCHASED FROM *Rxxxx* Technologies

To be fair, it *does* say on the *Rxxxx* website that the kit has "no bootloader installed or other FW/SW".
by va3rr
06 Apr 2022, 16:26
Forum: Group Buys
Topic: PL/EU Group Buy - SN3AK - I (completed) II (full)
Replies: 354
Views: 49735

Re: PL/EU Group Buy - SN3AK - **FULL/CLOSED FOR ORDERS**

It should be DGS, in my opinion. Also, there is a very minor error on the RF Board, because the Source is grounded, the pin hole should be square. Currently, the Drain hole is square.

sorry to be pedantic...
by va3rr
05 Apr 2022, 00:03
Forum: Troubleshooting
Topic: (tr)uSDX power, efficiency and filter optimisation
Replies: 177
Views: 28603

Re: (tr)uSDX power, efficiency and filter optimisation

Has anyone tried taking a *Rxxxx* kit, reburning the bootloader properly, reloading the software, and then testing efficiency? Maybe they are using the normal Arduino bootloader? Or, try swapping a new ATMEGA? Manuel has connected one of his RF Boards to a *Rxxxx* mainboard, and the efficiency is h...
by va3rr
04 Apr 2022, 19:29
Forum: Group Buys
Topic: PL/EU Group Buy - SN3AK - I (completed) II (full)
Replies: 354
Views: 49735

Re: PL/EU Group Buy - SN3AK - **FULL/CLOSED FOR ORDERS**

Where did you source your BS170? The RF Board BOM specified BS170-D74Z, which has Drain - Source -Gate, which also would be incorrect (I think).

The BS170's I bought from Kits and Parts has Drain - Gate - Source, which was only blind luck on my part...

https://kitsandparts.com/BS170.pdf
by va3rr
29 Mar 2022, 17:58
Forum: Troubleshooting
Topic: Questions about the rotary encoders
Replies: 10
Views: 1013

Re: Questions about the rotary encoders

Just swap the A line with the B line. I would snip the pins, bend them up, and solder insulated wire. WA2T made a board modification, I seem to recall...
by va3rr
29 Mar 2022, 16:50
Forum: Troubleshooting
Topic: Questions about the rotary encoders
Replies: 10
Views: 1013

Re: Questions about the rotary encoders

It's a common problem. When you purchase your encoder, the description should mention "In der Vorwärtsdrehung führt die A Leitungsphase die B Leitungsphase; im umgekehrten Fall führt die B Leitungsphase die A Leitungsphase". "In the forward rotation, the A line phase leads the B line ...
by va3rr
28 Mar 2022, 13:26
Forum: General Information
Topic: (tr)usdx calibration
Replies: 12
Views: 1933

Re: (tr)usdx calibration

Neven; I am also waiting on appropriate DC barrel connectors as well as rotary encoders. After some tweaking of my first RF board, here are my USB RF output and efficiency at 5V. Band pwr eff. dBm 80m 0.77W 84% 28.9 60m 0.88W 88% 28.9 40m 0.67W 88% 27.1 30m 0.84W 93% 28.9 20m 0.73W 81% 28.6 I will c...
by va3rr
25 Mar 2022, 01:37
Forum: Troubleshooting
Topic: C11 or C10?
Replies: 4
Views: 645

Re: C11 or C10?

C10 and C11 are in parallel, so it doesn't matter what slot one places the 68pF capacitor.

Look at the very end of https://dl2man.de/2-trusdx-assembly/ regarding different bands for an explanation why Manuel has this option available
by va3rr
23 Mar 2022, 12:13
Forum: Troubleshooting
Topic: (tr)uSDX power, efficiency and filter optimisation
Replies: 177
Views: 28603

Re: (tr)uSDX power, efficiency and filter optimisation

#43 ferrite has been used in QRP designs for years, as RF chokes and transformers. But if resistive losses are a problem for those contemplating 10 metre operation, perhaps a #52 or even #61 ferrite could be employed.

It's a little above my 'pay grade', though. I just like to solder...
by va3rr
21 Mar 2022, 18:45
Forum: Troubleshooting
Topic: Using nanoVNA to find cold solder joints in the RF board
Replies: 1
Views: 469

Using nanoVNA to find cold solder joints in the RF board

As recommended by Manuel, I've been using my nanoVNA to tweak the Lx2 inductors to tune the 2nd harmonic 'trap'. The RF boards I purchased for our group's 'boards only' buy did not have 1nF capacitors available when i ordered the boards, so I bought some GRM2195C2A102JA01D capacitors. When I was adj...
by va3rr
21 Mar 2022, 16:10
Forum: Troubleshooting
Topic: (tr)uSDX power, efficiency and filter optimisation
Replies: 177
Views: 28603

Re: (tr)uSDX power, efficiency and filter optimisation

Sylvain; With the 2 RF boards I have built so far, all the Lx2 coils were very close to F2 resonance, and required very little adjustment using the nanoVNA. Some of the Lx1 coils needed a turn dropped to increase the power output. I can only power my (TR)uSDX with the 5V USB connector at the moment,...
by va3rr
19 Mar 2022, 17:33
Forum: Troubleshooting
Topic: (tr)uSDX power, efficiency and filter optimisation
Replies: 177
Views: 28603

Re: (tr)uSDX power, efficiency and filter optimisation

I don't have any other FT37-42s, but I'm happy to order some if need be. For now, I've hooked up L15 to the nanoVNA and I'm getting about 200µH @ 50kHz but at higher frequencies the readings become silly, basically purely resistive above 1MHz. I need to check these results. The idea was to follow o...
by va3rr
17 Mar 2022, 14:19
Forum: General Information
Topic: Written assembly instructions
Replies: 7
Views: 3061

Re: Written assembly instructions

Is there any link with high resolution pictures with (tr)usdx PCBs with all soldered components when you are finished with soldering and with empty PCBs without soldered components you get in kit. 73 de Neven, 9A5YY Neven - because of my settings on my browser, I didn't realize that Manuel provides...
by va3rr
15 Mar 2022, 22:08
Forum: Troubleshooting
Topic: (tr)uSDX power, efficiency and filter optimisation
Replies: 177
Views: 28603

Re: Good results with *Rxxxx* kit?

This after tuning L32 for the 14MHz 2nd harmonic. Is this representative?

Image
by va3rr
14 Mar 2022, 12:33
Forum: Troubleshooting
Topic: No display
Replies: 15
Views: 1689

Re: No display

Until you flash the bootloader, there isn't anything to display.

Once the bootloader and firmware are flashed, I would test it first just with USB power only. Then if it is behaving normally, try 12 volts.
by va3rr
11 Mar 2022, 18:30
Forum: Troubleshooting
Topic: No display
Replies: 15
Views: 1689

Re: No display

0x78 is correct. When looking at the front of the OLED the pinout should be:
Gnd - VCC - SCL - SDA

Some OLEDs have them reversed.

Image