Home Build issue

[ZL3TCM]

Hi Guys
I have been following the Portsdown from down under and started construction, one issue I hope you can clarify. The filter components as per cct diagram and parts list vs photos seen here. The first photo of a completed early board I have attached but the component layout of the filter differs from the parts list and diagram can some one confirm the attached photo is old and obsolete ? I have seen a few photos on twitter BATC and they seem to match the component list and diagram

regards Rob ZL3TCM Christchurch NZ

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Edit by G8GKQ: This photo is of an early, incorrectly assembled, board and should not be used as a guide. Photos of correctly constructed boards are in subsequent posts on this Forum. Rob - thanks for bringing this to our attention and we're sorry for the confusion that it has caused!

[G8GKQ]

Rob

Where do you think it is different?

Dave, G8GKQ

[M0SKM]

The board pictured certainly has the filter components in different locations to mine. My higher symbol rate bandwidths look awful and I've been at a loss as to why. All parts are fitted as per the BOM locations.

Which is correct; the E and G inductors are transposed?

[ZL3TCM]

yes my issue was the location of the inductors rows G and I would assume as well that the capacitors maybe also installed differently ( hard to impossible to tell from a photo )

regards rob ZL3TCM

[G8GKQ]

Hi

We clearly have an issue here, as my board looks different

Portsdown Filter Modulator Small.jpg (426.13 KiB) Viewed 7896 times

I'll investigate tomorrow and post back.

Dave, G8GKQ

[ZL3TCM]

I agree Dave yours is a built by the BOM list and overlay

Rob

[G4KLB]

The circuit diagram and parts list are correct, the photo was of the very first prototype (Where we discovered the fact the filter components were transposed)

[ZL3TCM]

thanks for the clarification, wonder why Dave G8GKQ isn't having great sucess with his filters then

regards Rob

[M0SKM]

Hi Rob,

There's a little confusion; it's me that feels the filters on high symbol rates are not working well. As far as I know Dave doesn't have an issue with his Portsdown board.

I'm waiting for analyser pictures of the three higher symbol rates before looking into it any further.

PM replied to.

73 Steve

[g8gtz]

Hi Steve,

I've put some pictures taken from testing at 333Ks on the wiki here: https://wiki.batc.tv/Filter_Modulator_V ... ifications

It's currently still on the test jig - what else would you like to see?

Noel