I'm still waiting for resistors from China, silicon has all been mounted, but I'm still worried by the negative comments about Chinese semiconductors. The FPGA is programmed, so once resistors are in and fitted, I'll look at sourcing caps and inductors. The problem with SMT components are the multiples they are sold in; I could get all the passives from RS and they'd be in next day, but this would cost me over £100 and I' have loads of components I'm unlikely to need left over, so its trawling ebay for cheap components from China that takes weeks to arrive.
I haven't received my copy yet. I owe a huge thank you to Jeffrey for all his help and advice with the article. Jeffrey is a genius at technical writing. Among other things he edited it for me making some subtle changes that made it vastly more readable.
I had wondered if its the first time SMD had featured in a project or restoration within the magazine, I have only subscribed for a few years so not up on the past history. If it is the first time then its a milestone compared with the usual genre.
Again looking through the excellent data library on this site I came across this link to a BBC document about standards converters. Gives an very good insight into early designs.
Something to read with the drink of your choice in your hands, that could be tea or coffee.
Hi Frank The BBC research and development site is a great resource. We are so lucky to have it. It has many papers on standards conversion. A couple more example are:
Yes I saw those papers, I must admit a lot of it is over my head but I take in what I can.
The list on the Data part of this forum gives an easy to find link to the papers. Yesterday I spent reading about the site survey for what would become the Holme Moss Ch 2 BBC transmitter site and how they decided on that location. Then to Les Platons in the Channel Islands and how a 1Kw TX on Ch 4 would cover both islands.
A document on 3 cheap FM converters to be used with a MW radio to evaluate how well they worked, not very well was the outcome.
The BBC did a lot of R&D, presume it’s now very little if any.
I have been ask a few times if I would supply complete Hedghogs but as I have said right through this project I am not in a position to do that. Forum member Freya(Stephen) has stepped into the breach as he has told me that he is willing to supply complete Hedghogs. So anyone looking for a complete one, can get in contact with him.
I have updated the program so the converter can convert from 16:9 to both 4:3 and 5:4 as well as converting from 4:3 to 4:3 and 5:4. To facilitate this the top two positions of the tone switch are now used to switch between 4:3 and 16:9 input. The selection of 400 Hz or 1KHz tone is now done on the DIP switch SW8-D. The new program file and legends to suit can be downloaded from the Hedghog web page.
I have updated the program so the converter can convert from 16:9 to both 4:3 and 5:4 as well as converting from 4:3 to 4:3 and 5:4. To facilitate this the top two positions of the tone switch are now used to switch between 4:3 and 16:9 input. The selection of 400 Hz or 1KHz tone is now done on the DIP switch SW8-D. The new program file and legends to suit can be downloaded from the Hedghog web page.
After many months of collecting the components mostly from China, I finally had enough parts fitted to enable me to power up the board to see if anything would work. Much to my surprise it did ! As I'd mounted everything using standard workshop solder and iron, I was expecting some issues, but other than the R2R resistors which needed a few touches with the iron, everything else seemed in order. As I've not fitted the hex switch yet, I used an external modulator to test, however there was a spike at about 150Mhz so something is happening at RF. Now that I'm happy its serviceable, I'll get some switches and a box.
As you might notice, I mounted the crystal and 1N4001 on the wrong side of the board.
The power LED also flashes, is this normal ?
These are on the old 1400, with various linearity issues.
With regard to the cases there is another case that I believe does suit it is a Hammond RM2015S Available from Mouser and Rapid and probably more suppliers as well. I haven't tried it but the from the data sheet it looks identical and even the part number is similar.
With regard to the flashing LED it will depend on what version of firmware you have. looking at the test card you haven't got he latest version. You are probably better to up grade to it. But regardless of which version you have having all the DIP switches in the off position should stop the LED from flashing.
