3.4 GHz Transverter Conversion (3.5 GHz WiFi transceiver)

[VK2KYP]

Hi All,
I plan to bring my Panel down to Gippstech, I am travelling by car with Steve 2xde.

it is running low power about 250 mW due to one of the output FETS is faulty and I have disconnected it.

Is there any plans for other bands. I can bring down 1296 and 2400 MHz if there is interest.

73 Gary

[VK4CZ]

So close... but yet so far.

The 3.4GHz panel repurchased into a full tvtr with 20w PA... PA heatsink yet to be refitted and awaiting last couple of parts!

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[VK5ZT]

Scott

If you are ever going to want to move the IF to 432 or similar, put some pins in those six large holes near the micro
so you can reprogram at some stage. I will be explaining the process at Gippstech.

Cheers
Tim VK5ZT

[VK4CZ]

Tim... Tnx.... will be there taking notes.

[VK5ZT]

No worries Scott...

Also consider removing the stubs on each of the filters. They are useless for our application and only skew the filter response.

See the diagram below for how they are wired. Just a simple coupling loop inside the filter unit.

There should be a small bit of the loop poking through the solder near the point where the coax is soldered.
I think this was used to adjust the size of the loop. If you cut it flush then melt all the solder around the coax and wire you can push
the coax in to disengage the wire then pull the whole lot out.

Stub Removal

Stub Removal.png (4.79 KiB) Viewed 6392 times

You end up with a couple of bits of semi-rigid you can use elsewhere

Cheers

Tim VK5ZT

[VK4CZ]

Tnx Tim... be heading to the workshop this afternoon... will complete that then.

[VK1JA]

Tim, thanks for the tips, I'll do the same to the panels I have here.

If anyone has anymore tips, feel free to share here

[VK4CZ]

Coupling loop removed.





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[VK5ZT]

And another thing....

These boards can be extremely microphonic....they ring like a bell if not rigidly supported. (FM-ing of the pll)
I have had acoustic feedback from the radio speaker to the board causing howl-round!!

There's a reason there is three screws in immediate proximity to PLL1 when its bolted to the panel.
I would be inclined to put some foam behind the board when you bolt it down to dampen vibrations.
I even potted the pll in wax on one board...that did not fully stop the issue either!

Just so you know......

Cheers

Tim VK5ZT

[VK4CZ]

Micro programming pins added.... tnx again Tim. .



Looking word to hearing the updates at Gippstech.

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[VK2KYP]

Hi All,
Has anyone swept and measured the loss of the Panel filters? Before and after modifications

Thank you Gary

[VK7JG]

Hi Gary.
I did a Sinad measurement before removing the stub and for all practical purposes could not measure any difference in performance after removing them .
I don't have the capability of doing a swept response .

73
Joe
VK7JG

[VK2JDS]

Well, Steve vk2kfj, Steve vk2xde, Gary vk2kyp, Roger vk2zrh and myself have our panels here at Gippstech and are looking for expressions of interest in activating 3.4ghz sunday arvo.
Are any vk3's available, eg vk3mat, vk3amb or any others?
We can listen 147.225 repeater
73 Dave vk2jds

Edit :

We had a great afternoon out and about at churchill, morwell, tyers . Plenty of stations on air on 3.3982, and also a handy beacon on 3.400434 which was strong and gps locked !
13 operators with multiple panels set up ,on 3 different sites.

[VK3ALB]

Thanks to Dave Gary Steve & Steve for bringing your gear down for an excellent afternoon of 3.4GHz activity. We had a number of interested onlooker from our end and some of us even managed to work a US station all of 3m away

[VK3MAT]

Thanks all a lot of fun working on 3.4ghz

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[VK2KFJ]

Thanks to Dave Gary Steve & Steve for bringing your gear down for an excellent afternoon of 3.4GHz activity. We had a number of interested onlooker from our end and some of us even managed to work a US station all of 3m away

yes, very pleasing that others got to see them in action and try them, especially for those who have the panel but not completed them.
Mark VK5AVQ came over to The Ridge and we did some "workshop" testing comparing our panels against the VK3RGI beacon, we found Mark has a fault in his panel, suspect antenna, so he able to go home and fix it up, so it should work better next time.
I also learnt that VK1's JA and DA have incompleted panels, so I know I can throw my 3.4 gear in the car if I go to VK1 once they have finished them

[VK2JDS]

Yes it was a great afternoon after a very interesting Gippstech.
At the sunday lunchtime pizza munchathon I was chatting to Peter Freeman vk3pf and he was exhausted after all the work and had to head home asap. Thanks very much Peter and the crew for the great weekend !

The experience Mark had with his panel raises an interesting point . He found no change from horizontal to vertical pol when we were aiming at that handy beacon thats running about 30kms away from our test firing range.
Steves panel clearly nulled, as did both of mine, so it got me thinking about another panel antenna i had which had water inside it. Maybe Marks one had corrosion from water entry.

One of the panels i got was soaked in water, rusted out and stuffed, the antenna was same. From memory i think it did similar to what Mark is getting with his. It would be worth checking out before you all go out in the field just to see if yours nulls properly on polarisation change.

73 Dave vk2jds

[VK5ZT]

Hi Dave et al

Interesting about the water getting to the panel antenna. That is one of the issues with those things. It is too easy for water to get into the antenna in the right circumstances. I have a panel that appears to be 'non directional' so may have the same issue. They should drain if vertical but it very possible they were left piled up somewhere outside and water allowed to remain in the vicinity of the antenna pcb.
There is a gasket seal to try to protect the antenna but I have seen instances where water has seeped past this if left in contact for a long period.

I know how easy it is to fill them with water!

I will add that to my list of faults we have encountered....

Cheers all

Tim VK5ZT

[VK1JA]

G'day Tim,

Great talk you did on the panels at Gippstech, thanks for sharing the progress you've had with them and the software

Just as a quick update on the fault I have with a panel that the filters aren't peaking the rx - after hearing what Tim mentioned that in some cases the tracks go open circuit with heat (maybe removing the tin covers?) it's possible that one of the tracks on my board have gone open circuit between the tuneable rx filters and the first rx stage. It still receives the test (3.4Ghz) signal, but he test signal seems to be still getting into the circuit via the air ie not via the filters, as it makes no difference if the signal source is connected to the antenna port or not. And waving my hand around the input cable source makes the signal fluctuate.

More to come - when I get time....

[VK2KYP]

Hi I am looking for contact details for Mark vk5AVQ.

Thanks Gary vk2kyp