Classic band "option" - (tr)uSDX Forum (2024)

Hello,
I am a bit confused by the band descriptions. I understand that via the menu system one can choose the classic bands option, but do the different band options require different PC boards, or is the board stack the same for all band options?
Also, I understand the design is optimized for 80-20m, and not to expect great performance on the higher bands. However, does using the classic menu choice degrade the 80-20m performance?
When ordering a kit from one of the listed vendors, does one need to specify which band option will be the one being used?
Thanks!

Bob WB0POQ

Thanks for the info, but I'm still unclear about if the RF PCB is the same for all band choices and only coil and cap values are different or if there are unique and different (different copper traces, vias, etc.) PCBs for the Classic, High, Low etc. bands.
Some web sites I have visited have verbiage that strongly suggest there are significant layout, trace patterns, via placements etc. for the different band choices, albeit, most appear to be non English first language writers, so it may be due to my poor interpretation of the text.

Bob

It´s the same PCB for all Variants.
Only Filter caps and coils are different as well as PA Fet used.

73 Manuel; DL2MAN

Good Morning,

As mentioned several times before:
High Band and Classical Bands RF Boards are only available as Kits.
There´s too much tuning involved to provide this assembled.

If anyone wants to provide that service, I have nothing against it, but from my side there are no intentions in that direction. After all: (tr)uSDX was intended as DIY Kit and where´s a will there´s a way.
So: If you really want it, maybe it´s time starting to learn how to solder.

73 Manuel; DL2MAN

I’ve built my kit but it did not come with the 3 PA FETs. Am I supposed to de-solder the FETs from the standard board and re-solder them onto the Classic board?

Thanks.

Kevin, KN6WKm

chancekp wrote: ↑20 Jul 2023, 00:13I’ve built my kit but it did not come with the 3 PA FETs. Am I supposed to de-solder the FETs from the standard board and re-solder them onto the Classic board?

Thanks.

Kevin, KN6WKm

Hi Kevin, on the rf board, on the opposite side au toroids, you have to see the fet with three contacts already soldered.
73

chancekp wrote: ↑20 Jul 2023, 13:50The IC marked "DB15AB, 86256" is the PA FET?

The potency FET is usually identified as FDT86256.
73 Luca.

When reviewing the schematics posted for the classic bands, I noticed the number of recommended turns for the toroids differs between the schematic here:

https://dl2man.de/wp-content/uploads/20 ... _86256.pdf

… and here:

https://dl2man.de/wp-content/uploads/20 ... _v1.0n.pdf

For example, L21 is listed as having 7 turns in the former and 6 in the latter. There are other slight differences on some of the other bands. I am guessing the inductance can be tuned to notch the second harmonic in either case, but wanted to mention in case either of the schematics needed to be adjusted.

Thanks for all the support for this device, by the way.

VY 73,

Steve, W4SGN

Hi Steve,

one document is the official schematic by myself and the other document is one from external party, trying to make things more clear. I published that, because I thought people might benefit from it.
I did not check it for each and avery value, but when there´s no reasoning for a deviation from my original schematic, I would stick with the original.
P.S. There´s tolerances in every component from toroid cores over semiconductors to capacitors. This is why in one case, you might end up with one turn less and in another case you might end up with one turn more. In the end, you need to tune your individual PCB for best reults.

73 Manuel; DL2MAN