DATV Express on 6M

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G4KLB
Posts: 196
Joined: Wed May 28, 2008 10:46 am

DATV Express on 6M

Postby G4KLB » Thu Jun 22, 2017 12:43 am

The DATV Express is specified to work down to 100 MHz, but I read somewhere that it may work as low as 50 MHz.

Tests tonight proved that it is excellent on 70 MHz, but I've not had it working on 6M so far. Maybe the problem is with my up converter, so posting this to ask if anyone else has tried it.

4M.jpg
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G4GUO
Posts: 461
Joined: Tue Feb 16, 2010 12:51 pm
Location: Worthing

Re: DATV Express on 6M

Postby G4GUO » Thu Jun 22, 2017 4:57 am

Sorry to disappoint you Colin but the lowest it will do is around 65 MHz
this is limited by the internal VCO and the size of the divider chain in the PLL.

LimeSDR (see other thread) will do 50 MHz and 3.4 GHz out of the box and they
(Lime) have plans for an extender board that will also add 5.8 Ghz and 10 Ghz.

- Charles

G4KLB
Posts: 196
Joined: Wed May 28, 2008 10:46 am

Re: DATV Express on 6M

Postby G4KLB » Thu Jun 22, 2017 8:25 am

Thanks Charles,

That confirms what I found, 65MHz was as low as I had it working last night, but now I know why.

The comment ' The DATV Express board will also go to 50 MHz' I read here viewtopic.php?t=3952
Got me over excited :D

G4GUO
Posts: 461
Joined: Tue Feb 16, 2010 12:51 pm
Location: Worthing

Re: DATV Express on 6M

Postby G4GUO » Thu Jun 22, 2017 8:35 am

Look at the source of the rumour :)

I was lying in bed this morning thinking it wouldn't be too difficult to design an
extension board to add 50 MHz, 3.4 GHz and 5.8 Ghz to the board but it
probably isn't worth while as the demand would be too small.

- Charles

g0mjw
Posts: 317
Joined: Sat Sep 20, 2014 9:15 am

Re: DATV Express on 6M

Postby g0mjw » Thu Jun 22, 2017 9:34 am

I think there may be a demand to extend the range upwards if this could work with Portsdown as well. If you made it able to convert up and down it might be even more useful.

Mike

G8XZD-TV
Posts: 74
Joined: Fri Feb 22, 2013 6:41 pm

Re: DATV Express on 6M

Postby G8XZD-TV » Sun Jun 25, 2017 8:27 pm

I'd be interested.


Ian.

G4GUO
Posts: 461
Joined: Tue Feb 16, 2010 12:51 pm
Location: Worthing

Re: DATV Express on 6M

Postby G4GUO » Mon Jun 26, 2017 7:03 am

We are looking at it Ian, the hardware engineering team are working on another project
so I am looking at it as a personal project for the moment.

I am considering using a Hittite (Analog Devices) 9 GHz VCO.
They do one with /2 and /4 outputs which would be suitable for use on
10 GHz / 6 GHz and 3.4 GHz with a 1 - 2 GHz output from Express.
I am not sure how practical adding 10 Ghz would be as current cheap off the
shelf mixer chips only go up to around 6 GHz. 10 Ghz would probably have
to use a Teflon PCB and microstrip mixers and filters.

I already have a ADF41020 evaluation board (contains an 18 GHz PLL and uses an external VCO)
to play with.

https://www.dropbox.com/s/kynd3slo5smz7cl/DALk5oLUQAElikg.jpg?dl=0

It is all up in the air at the moment though and I am open to suggestions.

- Charles


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