Pledge: Rigol DSO
What
Bob's Rigol DS1052E - see https://groups.google.com/forum/?fromgroups#!topic/london-hack-space/xVia1vrydQo
1GSa/s 50MHz 8 bit 2-channel with 1 megasample storage. FFT, USB.
(storage and sampling shared over 2 channels, so 500MSa/s 500k samples in 2 channel mode)
Why?
We have a number of oscilloscopes but only one offers storage, the Philips PM3365A. Technology has moved on a long way from this early model and current devices are much more capable and easier to use. The Rigol range are well known as good and economical, and Bob is offering this current model at about half the retail price.
I don't suggest getting rid of the other oscilloscopes if this pledge is successful - the Philips will probably be little used but the analogue scopes (especially the Tektronix) remain very useful. Their traditional interfaces are fast and intuitive and their displays show how both digital and analog scopes can present misleading information.
Note : Bob's intention was to ebay this if he didn't get a buyer. However, I have bought it from him, so the pledge remains open and it can be bought from me instead if it succeeds. (I'm not donating the whole cost, sorry!) --Artag 12:54, 2 August 2012 (UTC)
Hacking
It's widely known that this oscilloscope can be hacked to operate to the same spec as the 100Mhz DS1102E model. The hack involves downgrading to earlier firmware, executing some (subsequently disabled) remote control commands, and then upgrading again. There is a small, but not insignificant possibility of bricking, and also the possibility, not guaranteed, of recovering the bricking.
There is evidence that the modification is actually worthwhile : there is some programmable control of the front end which does indeed raise the bandwidth. The 1GSa/s limit is not changed, of course, but the display permits a higher maximum scan rate. Since the 1GSa/s limit is over both channels, this is only really useful in single channel mode : Despite Nyquist's theorum, in 2-channel mode the 500MSa/s sample rate is only really enough for 50MHz (10x bandwidth is usually the rule for reasonable fidelity on current DSOs). This is especially true of FFT mode.
There may be some uses for the DSO which would make this worth doing. However, it's at the limit of operation, and many needs for higher bandwith don't also require storage. If you have a need for 100MHz, note that we have an excellent, working, 275MHz HP1725A. This will do a far better job unless you have a simultaneous need for the storage or maths capabilities. Please seek the permission of the people who paid for the instrument before taking the (relatively low) risk involved in modifying it.
Pledges
(Please pay to Artag, details on request)
- £20 -- Artag PAID
- £10 -- Sully
- £10 -- Phil PAID cash
- £30 -- Mark
- £15 -- Martin
- £10 -- Rob Kam
- £10 -- Dean Forbes
- £20 -- Steve Todd
- £10 -- David
- £5 -- PaddyD PAID cash
Running total: £140
Approximate target: £130
Paid: £35
