BATC DTX1 Questions and Answers

[vk4xrl-DATV]

4.268 MSym/s .......interesting / strange SR for a repeater input ?
Why so its a valid SR input?

Just seems an odd number - i.e. why not round up or down to the nearest hundred e.g 4.2MS or 4.3MS (or even just 4MS/s ) etc.
The extra 68KS or 32 less, wouldn't make any practical difference to the effective video quality for DATV purposes. Many coders / modulators will only cater for a fixed spread of rates, often at multiples with 0s e.g. 2000, 3000, 4000 etc.

http://www.spectra-bv.nl/dvb_modulator_lband.html . DTX1 also is adjustable to the nearest 100KS/s (at the moment - I hasten to add - sounds from one of the replies like a FW edit. might be in the pipeline!)

Thanks for your reply, however we have been using that SR for sometime now. It was set to that figure has we can have 3 x 6 MHz DATV channels within our 18 MHz FM band. Therefore according to the Excel chart for nearest 6Mhz bandwith and to provide the correct ratio SR/Fc, 4286 was the closest one. Some repeaters are using 5000 others 7500 so adjustment should be provided to make this happen. I am not sure what others so in Europe or USA are using?
Thank you, Richard VK4XRL

[2E0DTX]

Hi everyone -

Yes, a firmware upgrade is indeed in the pipeline. As it happens we had no idea that anyone would want to control the SR to such a fine degree but the beauty of having a flash micro in the DTX1 is you will be able to re-flash the unit to allow SR to be set to 3 decimal places. So rest assured this will be dealt with soon. We''l post a message when new FW is available.

We've just got back from a terrific time at Finningley - thanks all

73's

Laurence M6TTX & Carl M6GRD

[peterschrader2]

And another feature request if I may, HDMI input (or SDI), staying digital from PC to RF.

Perhaps a new expansion board can be designed to accept SDI or HDMI?

Cheers,
Peter
VK4EA

[g4wvu]

[quote="peterschrader2"]And another feature request if I may, HDMI input (or SDI), staying digital from PC to RF.

Perhaps a new expansion board can be designed to accept SDI or HDMI?

Hi Peter - interesting ( as I commented ) 3 x DVB signals in the original FM channel - sound good !

Yes agree about an expansion board with HDMI input idea - It had crossed my mind also - inevitably analogue video (composite or S ) is going to disapear eventually & this would future proof the general design / DTX1 unit. Not sure how technically difficult it is to implement but the DTX1's analogue input is obviously converted by an A to D to some standard (ITU656 ?) but I don't know much about HDMI ....

I'm sure laurence will know more

[peterschrader2]

http://www.vklogger.com/forum/viewtopic ... 567#p39567

A bit of cross promotion.

It's been fun so far, looking forward to getting a signal from our repeater sometime.

[2E0DTX]

Regarding DTX1 Symbol Rate;

We are testing a new firmware release candidate, which addresses the previously mentioned concerns over the fine setting of Symbol Rate. The new firmware will permit the rate to be set in 1kHz steps. It will also automatically preserve previous settings including those in any presets which may have been set up previously. Unless you need this fine adjustment there is no need to upgrade the firmware. We will post news when the release is available and put it on the support site www.dtx1.info as well.

73's

Laurence M6TTX

[2E0DTX]

Hi all

Please go to the support site www.dtx1.info for the new Firmware version 01.00.03 This firmware will adopt the new symbol-rate settings in KSym/s rather than MSym/s. Existing symbol-rates that are stored in the unit will be preserved and converted to the new standard. Note in this version, this value is also editable the same way as the frequency i.e. one digit at a time.

NOTE this is a feature enhancement not a bug fix, so users need not load it unless they require very fine SR adjustment.

73's

Laurence

[g4wvu]

new Firmware version 01.00.03 This firmware will adopt the new symbol-rate settings in KSym/s rather than MSym/s. Existing symbol-rates that are stored in the unit will be preserved and converted to the new standard. Note in this version, this value is also editable the same way as the frequency i.e. one digit at a time.

NOTE this is a feature enhancement not a bug fix, so users need not load it unless they require very fine SR adjustment.

73's

Laurence

I downloaded 01.00.03 - seems to work nicely ; I haven't run blind scans to check it empirically yet - but moving the SR up or down 5-10% results in out of lock until the new SR is entered on the STB so looks good (STB seems to lock over quite a wide range although it could be different when the signal is near the limit).
The SR is also quicker to enter by the digit replace method (rather than scrolling through all the intervening rates)
Thanks laurence.

[peterschrader2]

New firmware in, and good results from across the room testing. Thanks to the firmware team for a speedy response. I should be on air through our local repeater very shortly.

[2E0DTX]

OK Great!

Does anyone else have any comment on the new firmware?

We are about to program the next batch of boards, so feedback now would be very welcome!

73's

Laurence M6TTX