Moved from http://www.thereminworld.com/Forums/T/27484/big-briar-91-series-technology?Page=1
"Thanks! What are those end caps like? Can they be secured well enough to hold a Theremin antenna?" - Dewster
No. This is the weak link IMO, as they are just clip on and certainly wouldnt handle any stress. I have looked at drilling some holes in the extrusion and the end caps and having caged nuts or rivet / glued nuts to secure the ends.
For antenna mounting (both pitch and loop) I have seperate rigid ABS square profile extrusion inside the main extrusion, so that there is no stress in the main extrusion except on the reinforced base to which the square support is mounted.. This also allows the ends to be removed and the panels to be opened (you cannot get the seperate panels out with the ends in place) without having to worry about wires etc, as everything is fixed to the base assembly - One has seperate panel at the rear for sockets and seperate sloping panel for controls, and the mid-section panel that can be removed seperately for access to any circuit boards etc (my thinking is that this will be ideal for any tuning requirements, as one can simply remove this with antennas etc all in place, do the tuning, and put this panel back without having problems like one has with the EW enclosure) but no panel tough enough to support antennas unless one has reinforcement of some kind.
Oh - I double my sockets up to allow LH or RH configuration simply by plugging the antennas in one side or the other - extremely thin ecw is all thats needed to connect the antennas and this adds almost no capacitance - its glued to the inner plastic divider.
Fred.
rough sketch:
View from back.
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You may also be interested in something like this:
http://www.broadbandbuyer.co.uk/Shop/ShopDetail.asp?ProductID=15881
Aluminium version : http://www.marcocm.com/Bench_Trunking.html
and this
but a search for "bench trunking" and / or "dado trunking" turns up enough hits to keep one busy and confused for a long time ;-)
This bench type trunking is available in all sorts of forms, Aluminium, Steel and Plastic - I saw it as ideal for theremins, its certainly available in forms capable of supporting antennas (although some plastic versions may not be tough enough) -
But its much more expensive, and doesnt suit my ribbon instrument requirements - I am not really looking at theremin construction - I want to make a couple (one heavily modified EW, and probably one upside-down) to perhaps get the UD published by an electronics mag like EPE and the modified EW to be published on Element-14, but my real interest is in my ribbon instrument.
I have a lot of ideas for the EW - ESD protection and buffering certainly, FM feedback for tone shaping, but also my screw-adjustable antenna - I think that with the user tunable reference (tuning) control and the ability to tune the antenna capacitance at the antenna, the "tuning" control would in fact become a linearity control, and actuall tuning (setting the null point) would be done at the antenna..
Then I will also add a "slave" mixer or two, to increase the available tone pallette hugely - make these other waveforms frequency dependant (using a 'tilt' equalizer on each)... And add comprehensive preview and audio mixer driving a good headphone amplifier, so that preview, main and an external audio input can be mixed to taste..
Fred.
