Digital ATV

Digital Video Broadcast or DVB comes in many forms and fashions:

DVB-C - This is the DVB standard used by cable providers.
DVB-S - This is the DVB standard used in Europe by the Satellite Broadcasters.
DVB-T - This is the terestrial standard used in Europe and many parts of Asia for local HDTV
ACSB or 8VSB - This is the standard chosen by the US Broadcasters

After a great deal of research, study and talking with hams in Europe, I have decided to build this ATV repeater based upon the DVB-S standard. There are many reasons for this. I looked very hard at 8VSB(common HDTV) and I concluded that it is just too expensive to construct. The modulators are not found surplus yet and the A3C audio is hard to come by. Although the Divicom encoders can do it, a software upload is required. I dont have the funds needed to buy the software ($8,000). So here is the idea. We have all the parts needed to do DVB-S tx, there are still decisions to be made as to what the final output freqs will be and what the inputs will be.
It will not matter what standard is used, to receive DATV some form of set top box or converter will be required to demodulate the QPSK signal coming from our transmitter. I regularly see Free to Air (FTA) Satellite receivers on EBAY daily for less than $50. These units are what the hams in Europe are using with very good results. I would love to put the primary tx on 1255 mhz, but getting clean high power up there is not going to be easy. I am looking at 2395 mhz, 3440 mhz and 10280 mhz. Right now I can put all three of these freqs up at the same time, but do we really need to? the answer is YES, why?
Because we dont know what freq band will have the best performance. I am guessing that 3440 mhz will be a good contender because low cost expanded range LNB's are available. There are pros and cons to all I have discussed. There will be much input from people who will be testing this thing trying to determine what will work the best.

I wish to thank the following people for the contributions and information given to me so far:
KD6W - Joel Wilhite, without Joel this simply would not be happening!
N6OLD - Bill Kasier, Bill has been an inspiration to me through out the years, he has been a big help.
WB6ASU - Fred Coe, Fred has spent the better part of last month in interdigital filter 101 and linear amplifier 101
KJ6KO - Greg Stahlman, Greg is the source for information on surplus amplifiers and parts.
F4DAY - Jean Franqois Fourcadier. Jean is hard to follow his English is no better than my French, but we have had some good interaction on building a low cost DATV uplink tx'ers for the shack.
M0DTS - Rob Swinbank, Rob and I are working together with F4DAY to build low cost DATV Tx for the shack.

Testing has begun now on our Digital ATV repeater!!!!!

Here is what we have done so far:
08/10/2008 -
Setup International Datacast DVB-S modulator to test mode, started testing different FTA receivers.
So far all receivers look good and can decode the modulator.

09/15/2008 -
WOW!!!!! such a deal, the ultimate find....
I have aquired a Divicom MV-10 MPEG2 ENCODER and a Harmonic DVB-S modulator.

09/18/2008 -
Setup new encoder and modulator to a video camera. I now have datv transmitting on 1250 Mhz on the bench. The 1 second delay is new to me. But the picture clarity is awsome.

09/24/2008 -
I have setup my Sony commercial satellite receiver to recieve on 1289 mhz. I now have my 1.2 ghz Mobicomm TX programmed to 1289 mhz. The picture on the Sony is less than desireable. I tried another satellite rx, different mfg., same result. I modified the Mobicomm 1.2 ghz tx, this made all the difference in the world.

09/26/2008 -
I have the output of the Sony satellite rx feeding the Divicom encoder. I now have DIGITAL ATV working in the repeater mode. I am receiving on 1289 mhz FM and rebroadcasting at 1250 mhz DVB-S. I am running about 6 watts on 1250 mhz

10/8/2008 -
I have taken the Globecast RX, the Sony Trinitron monitor and the Mobicomm 1.2 ghz FM tx on the road, I have been as far as 3 miles, I still have a P5 picture from the DVB-S Tx. I am putting in a P4 picture into the Sony satellite rx, but I did not bother to put an LNA on the satellite rx because I have no duplexer as of yet, but WB6ASU is working on that right now.

10/12/2008 -
What to put all this in....the Divicom encoder is 27 inches deep. All my repeater cabinets are way to short. I have bolted 3 separate, 42 inch Micor repeater cabinets together, I have an ugly 30 inch deep cabinet but it works. I now have the encoder, modulator and all the pre-wiring completed. I have made the brakets for the Sony satellite rx, I do plan to have multiple outputs and inputs to the repeater. I have aquired a quad color video processor for simultanious inputs.

10/15/2008 -
I now have 40 watts operational on 3440 mhz
I now have 60 watts operational on 2395 mhz.
The spectral purity on 3440 mhz is very clean. 2395 mhz shows just a little re-growth.

10/17/2008 -
I now have 2 watts solid state on 10280 Mhz, this is a longshot, to receive up here we will have to use Dish TV LNB's and I dont know how well they will work without modification.