On 21/06/2013 14:33, cecco.delprete wrote:

I notice that on 20m the power output drops dramatically (~50%).

Hi Francesco

I noted a drop in power after 10MHz in my tests but didn't worry about it, not 50% at 14MHz but a full drop 50% at 18MHz which the rises to give more power on 28MHz. It is a simple design, not optimised for any band, QRP, and after all its only a 3dB drop.

Necessary fine-tune the LP filter?

I don't think you do do anything to optimise the LPF.

Or are other problems: eg. DDS-VFO?

Have you got results above 14MHz, adjustment of the blue Mark Space adjustment pot is quite critical, I find adjusting for max RF power out to the antenna on 28MHz is as good as anything.

73 Eddie

Nice and neat, and compact.
Thanks for sharing.

73 de Andy

On 19/06/2013 15:56, andyfoad@... wrote:

have just put my U2 in a box, I will get round to some pictures and a
few words in time.

Come on - hurry up !

OK Slave Driver

The quickest way was a Web Cam video which does give an accurate impression of size.

Thoughts were:- Small size, light weight for portable use, ergonomic 2 thumbs operation of the Menu Buttons, internal 5V regulator, all sockets on the rear. No visible fixings, take the LCD display, those 3 odd fixing points, clearly it was not made to be through panel mounted.
The LED indicator above the Right Hand push button does not flash on and off, it is a spy hole down to the DDS LED, a job for a light pipe when I can find one.
On the rear:- SO239 antenna skt., 6pin miniDIN GPS socket, 2.5mm 7.5 to 15V DC in.
Band LPF changing is easier than when the board was laying on the bench being presented edge on at the top right of the case. Temporary operation on a band with an external LPF is via a plug in adapter lead which can sneak out of the top of the front panel.



73 Eddie G3ZJO

To forum, help me please.

Have a question.
I notice that on 20m the power output drops dramatically (~50%).
Necessary fine-tune the LP filter?
Or are other problems: eg. DDS-VFO?
TKS Francesco, HB9AFZ

On 19/06/2013 23:25, Hans Summers wrote:

It's great fun operating from locations you don't normally operate from

Yes and with the U2 being capable of knowing where it is (although I might be unsure) and inserting the QRA Loc. automatically. I am looking forward to the Trimble GPS compatibility being restored.

Time is running short now before I leave these cold soggy shores, touring in search of better climes and I was looking forward to pulling up and throwing the U2 into a bush with an antenna and activating some 28MHz WSPR.

Eddie G3ZJO

--- In QRPLabs@..., Hans Summers <hans.summers@...> wrote:

locations you don't normally operate from, and being QRSS it is
automatic operation so it doesn't subtract too much from your
family holiday either!

I think that's the key to it all.

Throw up a wire in the nearest coconut tree, leave a U2 running
and come back later after the beer has run out to check the
results.

Said in jest but true.

Building QRSS kits satisfies the need to build something as well
as providing the insight to radio propagation and investigations.

73 de Andy

LOL!

Maybe this one would be suitable for Eddie's hot 6m PA ..?



;-)

I'm now considering an old fashioned WOODEN box for a picnic
portable, just to be different ;-)

Nah!

It's got to be one of these to house it...
Room for some boiled eggs and soda pop too :)




Philip G4JVF

开云体育

--- In QRPLabs@..., g3zjo <g3zjo@...> wrote:

On 19/06/2013 14:14, andyfoad@... wrote:

Yes I suppose it all depends upon how the individual likes to
design their gear.

I do like to see the various approaches to boxing the same project.

It's why I also like SPRAT. Always good to see how others innovate
their unique contraptions ;-)

have just put my U2 in a box, I will get round to some pictures and a
few words in time.

Come on - hurry up !

The Picnic Portable has sparked the imagination, what a wonderful
idea, plenty of room in the cabinet for a flask and sandwiches,
couple of bananas etc.:-)

I've got a few ideas, anything could happen in the end.

I was hoping to have something ready to take on holiday but I don't
think time is on my side.

I like the idea of stringing up a wire for 600m /P and playing WSPR
sometime. Assuming the sandwiches and the bananas don't get in the way ;-)

My box is the opposite very compact.

Said the actress to the Bishop !

Regards,

Andy

Ooops, I forgot. I hope that this is working now:

But it is not a U2 :-)

72 de
Hajo

---
... indessen wandelt harmlos droben das Gestirn
...

On 19/06/2013 15:12, andyfoad@... wrote:

Unfortunately I cannot see the photo.

Wooden is no good, its got to be fire proof for when you try to run it on 50MHz.:-)

Eddie

On 19/06/2013 14:14, andyfoad@... wrote:

Yes I suppose it all depends upon how the individual likes to
design their gear.

I do like to see the various approaches to boxing the same project. I have just put my U2 in a box, I will get round to some pictures and a few words in time.
The Picnic Portable has sparked the imagination, what a wonderful idea, plenty of room in the cabinet for a flask and sandwiches, couple of bananas etc.:-)
My box is the opposite very compact.

73 Eddie G3ZJO

Unfortunately I cannot see the photo.
Yahoo groups has blanked it out :-(

73 de Andy

Andy, Something like that?

72 de
Hajo

---
... indessen wandelt harmlos droben das Gestirn
...

Hi David,

Yes I suppose it all depends upon how the individual likes to
design their gear.

Personally I like the all in one approach where ever possible.

I hate carrying box, batteries, cables, more accessories and
anything else with me, so I tend to go for the everything in the box
approach.

Although my current GPS intended for home use by default used a
waterproof gasket sealed plastic box simply because it was the
only box I could find that had the right size for the PSU + GPS
and output connectors (dual output to run both a U1 and a U2 at
the same time.

I'm now considering an old fashioned WOODEN box for a picnic
portable, just to be different ;-)

Happy building !

73 de Andy

Andy, et al

Well, of course you could glue a lid on, but that raises more problems than
it solves for me.
If you just want a radio-transparent waterproof annexe to the U2 case,
gluing a lid over the GPS module would work. But a waterproof box is
probably cheaper (less than ?8 for 5 on ePay), has a complete seal, and is
easy to open for access to the module.

I wanted to tuck the U2 out of the way, with its antenna running away as
usual and with the GPS antenna in a place where it has a clear view of the
sky. For example, the U2 keeping dry with me in the car with the antennas
fed out of the window.
Of course, I could extend all the leads to the GPS module and put it in my
waterproof box, but GPS antennas are designed for this when the PPS signal
is not. Heaven knows, we are having enough problems with this aspect of the
U2 as it is ;-(

So, I'll wait for my new software, and hope to get one of the 'separates'
working with it.
Of course, I was silly enough to order an additional U2 at the same time as
the replacement software, so I am at the mercy of Hans' suppliers for
timings.

David
G8XBZ

The reception reports will have to wait until the updated firmware chip arrives so that I can get a 6 meter signal out of the U2... Else, I have a design that will fit. Also, waiting the filter boards so that I can build the design to fit the U2... They should be in the same shipment.

Good challenge, though!

Paul KE7HR