Portsdown boxing/build thread
Posted: Wed Sep 19, 2018 1:26 pm
After seeing several installations at CAT18 I'm now progressing my own build. Thought it would be a good idea to start a build thread (mechanical) rather than electrical/electronic although its all intertwined somewhat
One very neat idea I saw was mounting the RF switch output SMAs on the back of their PC board, then mount this board on the inside back cover. Thus saving a lot of connectors and coax. Yes you can still screw on the connectors.
I have the PE4302 attenuator in and working, having tested it by using the Portsdown signal generator function. From what I've read this uses a different output from the DDS so needs its own cabling and socket on the back to provide a handy attenuated (by up to 31dB) test signal.
I've uncased my RTL dongle - they run hot anyway and that then allows direct plugin to the RPi USB without obstructing the port above. I'll probably do the same with the VideoDVR dongle for similar reasons.
I found these on eBay https://www.ebay.co.uk/itm/USB-2-0-Pane ... 2749.l2649 and these https://www.ebay.co.uk/itm/RJ45-Cat5e-M ... 2749.l2649 which will do a neat job of externalising RJ45 and a spare USB.
SInce it all runs off 5 volts I found a nice 5 volt 5 amp mains SMPSU in my big box of old SMPSUs. That will be load checked and tweaked up if required. A facility to provide 12 volts nominal from e.g. a car will be added, probably feeding a buck converter from ebay.
Finding a suitable box proved tricky, not sure how much I might ever end up adding etc etc but I settled on this one. https://www.ebay.co.uk/itm/ABS-Instrume ... 2749.l2649 Not cheap, but hopefully a tidy solution. Its roughly the size of an A4 sheet of paper.
Wondering how much the final 4 way electronic switch can handle - I can't find a figure for pass-through watts....correction, 16dBm = 40 mwatts? Is that right?
Finally, do I need a sound-card dongle for the RPi? The webcam has audio input, so does the Video capture device. I'm guessing YEs for the RPi camera which I also have hooked up. I've some 'Daffodil US01' USB sound adaptors that include volume buttons and a mute i/p &o/p button. ANyone used this?
Now to give some thought to front and rear panel layouts......
Gareth
One very neat idea I saw was mounting the RF switch output SMAs on the back of their PC board, then mount this board on the inside back cover. Thus saving a lot of connectors and coax. Yes you can still screw on the connectors.
I have the PE4302 attenuator in and working, having tested it by using the Portsdown signal generator function. From what I've read this uses a different output from the DDS so needs its own cabling and socket on the back to provide a handy attenuated (by up to 31dB) test signal.
I've uncased my RTL dongle - they run hot anyway and that then allows direct plugin to the RPi USB without obstructing the port above. I'll probably do the same with the VideoDVR dongle for similar reasons.
I found these on eBay https://www.ebay.co.uk/itm/USB-2-0-Pane ... 2749.l2649 and these https://www.ebay.co.uk/itm/RJ45-Cat5e-M ... 2749.l2649 which will do a neat job of externalising RJ45 and a spare USB.
SInce it all runs off 5 volts I found a nice 5 volt 5 amp mains SMPSU in my big box of old SMPSUs. That will be load checked and tweaked up if required. A facility to provide 12 volts nominal from e.g. a car will be added, probably feeding a buck converter from ebay.
Finding a suitable box proved tricky, not sure how much I might ever end up adding etc etc but I settled on this one. https://www.ebay.co.uk/itm/ABS-Instrume ... 2749.l2649 Not cheap, but hopefully a tidy solution. Its roughly the size of an A4 sheet of paper.
Wondering how much the final 4 way electronic switch can handle - I can't find a figure for pass-through watts....correction, 16dBm = 40 mwatts? Is that right?
Finally, do I need a sound-card dongle for the RPi? The webcam has audio input, so does the Video capture device. I'm guessing YEs for the RPi camera which I also have hooked up. I've some 'Daffodil US01' USB sound adaptors that include volume buttons and a mute i/p &o/p button. ANyone used this?
Now to give some thought to front and rear panel layouts......
Gareth