I know how you feel as I have done similar. You don't want your cameras at soffit height though, unless you live in a bungalow. The cameras will be too high and you'll just see the tops of people's heads. Ideally you want them around 2.5m off the ground.
I bought some electricians rods. I run my cables up inside the cavity of the house to the loft. They come up just behind the soffit. What I do is drill an 8mm hole where I want the camera at as steep an angle as I can and go through the outer brick, I then feed the rods through until they reach the top (sometimes there is insulation in the way). I then go into the loft and get the end of the rods and attach my CAT5e cable (you could use CAT6 but CAT5e is cheaper and easier to work with and fine for PoE cameras). Then back outside I pull the rods back down and the cable through the hole. RJ45 end fitted and camera on the wall. I then need to go back into the loft and run the cable to where I want it and fit another RJ45 end (if connecting directly to the NVR/PoE switch) or punch it down on a patch panel.
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Funnily enough I actually bought THIS kit a few months ago, to hopefully help me:
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But it's actually too stiff to use to get round the bend enough
For the record, yes, It's a bungalow
I literally just went outside with a tape measure to double check
The holes I've made to take the cable (will be the middle of the camera) is exactly 2.4m from the ground.
I hear your recommendations and know what you mean, it's just really hard.
If you can imagine, I'm at the very front of the roof, in the loft, so it's all down to almost no height, and laying on stomach, with arm outstretched can just feel over the edge of the internal brickwork.
So the cable has to go down this gap, and into the soffet area, then move away from me, past the end of the brickwork, and then loop around, and back up to find my hole!
It's hard to explain without pictures!
I got lucky elsewhere. I got two flexi rods with a strong magnet taped to the end, poked out in from outside, and went fishing (blindly) in the loft, and managed to get them to connect.
However at this location I just did not get lucky.
I could be literally 1" away or 18" away I don't know.
LED's on sticks and Camera's on flexible rods will be next attempt I guess...
I could tie the cable around a mouse, poke thru hole and place cheese in the loft and hope!