BATC Forum

Please post your BATC DTX1 Questions and Answers here for the benefit of other members.

Besides the suggestion for using a temp inline duplexer/triplexer to aid with filtering of output prior to input to final amp, what other methods are easiest for filtering output.

Compared to the SR systems "Hamset" boards - is this a step forward - or essentially the same technology presented in a different way?
(and less hassle to get hold of in the UK)

Might be able to answer a few Qs. Been playing around with a pre-production (Beta FW) DTX1 for some months.
Essentially does the same job as an SR systems DVB-S unit (MPEG encoder is a Fujitsu LSI chipset , onboard 140-2150 mhz synthesizer & QPSK modulator, Xilinx FPGA doing the framing & coding etc.) However its all on one board having been designed for DVB-T commercial distribution use originally (Hotels, corporate etc.) It has a header for external MPEG 2( or possibly MPEG4 soon) encoders, so is expandable to multi TS. Inputs are all on the rear & no multiway ribbon cables or connectors to displays or controllers are required. The only connections required are 6 wires for 5 switches (5+ 1 common) to directly control all parameters - shown on a two row display on the board edge.

I have one here (cased version) & its perfomance is as good or better than the SR unit I also have in most areas. Max RF output level is around -5dBm (as opposed to +4) ....only possible minus, but the level range is much wider (100 steps at ~0.5dB as opposed to only 15 rather coarse on my SR). Close in spectral purity is better (I think sharper (Bessel) filters on the I Q signals) by about 10dB generally. Generally a good piece of kit for generating DVB-S at a very reasonable price(via BATC - board version). Unit additionally has 3 memories which are usefull

A question has been asked by Mans 9H1GB on email and answered as follows -posted FYI:

Question:
Apart from the assembled board, does it come with the 5 switches for up,down, left, right, OK buttons and the RS232 cable.

Answer:
The bare PCB system at £399 only has the display and not the switches nor the RS232 cable – the wiring for the keys is in the user guide at http://www.dtx1.info/

The system with case parts (out of stock until next week) comes complete with case and front panel with switches.

Has anybody tried to set the symbol rate to 4.268 MSym/s, out local ATV repeater requires this symbol rate. I've got the DTX going across the room at 4.2M to a SelectTV STB no problems.

Or ca the Sym rate be set to a custom figure using the RS232 interface?

Hi Peter

Symbol rate can be set in 100kHz steps presently. Do you need more accurate than that?

Please drop an email to support@dtx1.info and we can discuss offline.

Thanks

Laurence M6TTX

4.268 MSym/s .......interesting / strange SR for a repeater input ?

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

vk4xrl-DATV wrote: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!)