1 Apr 2013

Tripods for optical comms

The one I missed on eBay
This evening I was annoyed with myself for not bidding for a tripod on eBay in time that went for just £6.50 in the end.  It had a nice solid structure and a 360 degree marked calibration on the horizontal pan adjustment and would have been ideal for my non line-of-sight optical comms over the horizon, where the ability to return accurately to a know bearing is important when hunting for weak signals.

So, can readers make any recommendations for something similar?
My requirements are:
  1. Solid construction so it won't wobble around in wind with the optics and detector mounted on top.
  2. Some way of calibrating the direction to within a degree or so horizontally so that known directions can be confidently returned to. Ideally a large 360 degree marked scale.
  3. A way for leveling the head assembly so it can be aimed just above the horizon.
  4. Low cost as I am looking for an inexpensive solution (don't want the tripod and mount to cost much more than the rest of the kit, which is about £5-10 total!)
Not being a great photographer, I know little about tripods and heads. Looking on eBay I didn't find anything close to the one I missed. It was SO annoying as I only missed it by 5 minutes having been out treating a fence in the (rare) sunshine today.

4 comments:

Graham said...

Roger, you have a tall order in your requirements of a tripod and at an inexpensive price too. Usually the two are at odds with each other.

Manfrotto is a top notch name in tripods and would server you well for many years but at a cost.

Keep in mind that the heavier a tripod the better it will be, generally speakig, stability wise. In this case heavy and portable are at odds.

Something you can do to enhance the stability of a lightweight tripod is to hang something heavy (rock, camera or equipment case, etc) from the center of the tripod underneath between the legs. This is an old photographers/astronomers trick and it does work.

Something to look for that might just fill the bill is an old used surveyors tripod. Often with wooden legs and metal fittings, usually stand several feet tall without extending their legs. Their feet have pointy ends which can be pushed into suitable soil. The challenge then becomes mounting whatever you have to the tripod.

cheers, Graham ve3gtc

xlsage said...

Hi Roger,

Here are a couple of items that I have on my shopping list for my own planned experiments in optical communications. Note that I have not tried either yet.

For monitoring elevation adjustment I thought this little inclinometer looked like a bargain at:
http://www.tool-net.co.uk/p-348112/tool-net-100mm.html?gclid=CKvx7-i8rLYCFeXLtAodmzIA6Q

And for adjusting elevation only this might be of interest:
http://www.wexphotographic.com/buy-manfrotto-234-monopod-tilt-head/p11018

For directional adjustment the following rotating head might suit (although a bit pricier):
http://www.cromwell.co.uk/STX5855350P

The above would, for instance, fit on this tripod (again a bit costly):
http://www.cromwell.co.uk/STX5855330M

Regards Jeremy (sorry I have no callsign)

Anonymous said...

Buy a department store telescope. You can use it to teach your grand kids about sun spots and nature. When they are not around, use the tripod for your experiments.

-Rupert, Florida USA

Roger G3XBM said...

Thanks for the suggestions. A surveyor's tripod sounds a good investment although I'd still need to find a way of being able to calibrate direction accurately.