My now quite dated DIY 'scopeless'NV build.

[Dave-G]

To avoid further de-railing Bob's home build rear add-on NV thread I thought it best to bring any further interest in crosshair generator rigs or 'scopeless' builds as they have been dubbed into it's own thread.

 

I can also post up the build details of my Watec 902H add-on rig if anyone wants to see it.

 

Here is a copy and paste of the first post in my thread which was originally made over a year ago on another forum which can be found by googling this:

Watec based dedicated NV home brew rig.

 

 

I first thought about extending the possibilities of our Watec based homebrews (and mentioned it on the BBS) several months ago (that's now about two years ago) - but baulked at the idea of sticking some thin black 'go faster' car trim tape on the monitor to act as a crosshair. A member of another forum brought a Crosshair Generator device to my attention a few weeks ago which re-awakened my interest on omitting the day scope which blocks so much light from our various Digital homebrew projects.

http://www.ebay.co.uk/itm/170698288339? ... 1438.l2649

Well here it is all fitted up for a preliminary trial which will hopefully improve as I go along. Minor issues I have at the moment is the vertical crosshair has what looks like ghosting around it. It seems to be a black curser placed into a thicker white one. It didn't show up in this clip very much but it's very apparent on the small LCD viewing screens I have tried thus far - as well as on my PC monitor. I suspect the issues would be less apparent with a thicker crosshair and the producer has in fact implemented that into revised software on currently available retail ones.

An unforseen issue is that our Watec 902 camera's are black and white - so the choice of black or white crosshair may result in it disappearing on a dark or light target. I rather hope a red crosshair becomes available. Despite this I am very very impressed at the potential now available. Unfortunately I won't be videoing very much of it because the PV110 DVR I used here only has a 2.5" screen that isn't very kind to my 60 years old eyes. The other DVR I have is that ****ty effort called JXD990 which blooms out at any decent level of light that doesn't affect other viewing or recording devices.

A peek in the cupboard under the stairs after building it:

I discussed the ghosting with the crosshair generator manufacturer who advised me it's it's known as 'video bounce'. It's something to do with low cost video camera's not being exactly the 75 ohm resistance they are supposed to be. After a quick Google I found this site offering supporting information, but I've not yet found the fix:

http://www.fmsystems-inc.com/index.cfm? ... ail&pid=17

I did some more Googling and found this:

http://www.hinesight.com/video/videosetup.htm

If I've understood that correctly the 75 ohm termination needs to be as it says on the box - at the terminal end which in this case is the monitor. At the moment Ithink there are 75 ohms at the camera outlet and the crosshair generator input. I don't know yet if the monitor has one too.
Screwdriver is on standby for taking the back off the monitor but I'd need to find what resistor value will do the deed. I'm waiting to hear back from the producer of the XH300AS crosshair generator first.

Just as I was about to pop out for a zeroing session it started raining so I took some pics instead.

http://img.photobucket.com/albums/v695/ ... Rifle0.jpg

http://img.photobucket.com/albums/v695/ ... Rifle1.jpg

http://img.photobucket.com/albums/v695/ ... Rifle2.jpg

http://img.photobucket.com/albums/v695/ ... Rifle3.jpg

It's not as heavy as I thought it would be. The monitor will swivel for transit in the rifle bag and to
let a passenger in the 4WD see the shot. The crosshair adjustment increments look nice and small.

It's still too mucky to go out for a zero session but I lashed up/swapped the monitor for a PV110 DVR.

http://img.photobucket.com/albums/v695/ ... 110DVR.jpg

I've trimmed down the high gain of the Watec a tad and I'm pleased at the results so far. Being as the crosshair is such a prominent black it doesn't get lost as much as I thought it would against dark backgrounds - when I have the IR on. The 1 watt IR drop-in looks like it'll do me for at least FAC air ranges if I'm using the DVR - or rimfire ranges when using an LCD monitor which gives vastly superior image qualities.

I anticipate not needing any IR at all for FAC air ranges when there is half decent star or moonlight about (as seen in real time on the monitor - before the image is de-graded by upload, compression then download from youtube).

 

That's where I'm at so far, I'll update as and when I can get out with it again but the weather don't look too good at the moment in regard to getting electrical stuff wet.

I realised the battery got locked in the gun cabinet every time i put the rifle away so removed it so i could recharge it as needed. It now gets Velcro'd to the side of the project box.

 

http://img.photobucket.com/albums/v695/Dave-G/CvcloneDedicatedNV2.jpg

 

Here's a link to it's christening;

 

http://forums.pigeonwatch.co.uk/forums/topic/225424-dedicated-night-vision-home-brew-rig-christened-this-morning/

Edited September 14, 2013 by Dave-G

[boo]

Disapointed Dave! No nicely venerred plywood in sight......

[Davyo]

Hi boo, I am realy interested in having a crack at this using the sony sj230 that has the facility to created cross hairs and I am sure Rolaids said its also poss to create mil dots.

[boo]

Easiest thing to do is get over to the NVUK forum,there are a few guys building scopeless,using the ej230 others cross hair generators,some really clever stuff on builds,mounts,lenses,etc would be your best bet,a lot of info is already on there,and just ask,they don't bite....