Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Sat, 09 Jul 2011 14:51:15 +0100
There's no reason what you have done should be non-linear. Perhaps there's a diode been put in the meter to prevent damage due to overvoltage. That could clamp the range. It's a bit silly, as its alr
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Sat, 09 Jul 2011 22:26:40 +0100
I'd be tempted to open the meter and see if there is a non-linear device in there - most probably a diode. One thing that's very important is that you stop the meter voltage ever rising too high if t
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Sat, 09 Jul 2011 22:32:09 +0100
But it should not be necessary on a volt meter. If the scale is significantly non-linear, something is very wrong. It's a bit different with for example a power meter which covers a wide range of fre
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Sun, 10 Jul 2011 03:03:46 +0100
What's wrong with a DC regulator? -- A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing i
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Sun, 10 Jul 2011 09:28:53 +0100
Do you have specific size constraints? If not, it should be fairly easy to find something to do the job, without it being a Sprague d74549 7834L., Dave -- A: Because it messes up the order in which p
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Wed, 13 Jul 2011 13:27:35 +0100
Do you need the pulsed version (P in the part number)? The 3CX800A7 is far more common than the 3CPX800A7. Without looking at the data sheets, I've no idea how similar they are. There are tons of 3CX
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Wed, 13 Jul 2011 16:36:49 +0100
They are the official distributor for those devices - their prices will not be cheap. -- A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing?
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Wed, 13 Jul 2011 21:03:05 +0100
Assuming you are talking about this auction http://cgi.ebay.com/Eimac-YU-158-8877-3CX1500A7-Power-Triode-/350477144083?pt=LH_DefaultDomain_0&hash=item519a10d013 it's possible the "1" looks bigger due
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Thu, 14 Jul 2011 21:28:56 +0100
To be honest if a company is capable of making an electron tube, with all engineering that needs, then creating an Eimac silk screen, I'm sure they would be capable of getting all the letters the sam
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Fri, 15 Jul 2011 22:23:14 +0100
I've had a couple of deals go wrong with hams. In both cases it was not deliberate deception, but stupidity on the result of a ham advertising something as X, then sending me Y. 1) I bought some diod
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Wed, 20 Jul 2011 08:11:27 +0100
That is quite acceptable. Tubes don't mind that. Strictly you are going above the voltage, but I don't think it will harm any tubes. I've seen that written in some data sheets, but I would certainly
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Sat, 13 Aug 2011 09:49:02 +0100
These is an equation, based on the physics of semiconductors, that shows: P f^2 R = constant. P = power f = frequency R = output impedance I can't recall the derivation of that, but could dig it out.
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Sat, 01 Oct 2011 17:36:16 +0100
I expect so, but have you checked the data sheet? There is bound to be that information in there. There a data sheet on my web site. Dave, G8WRB. -- A: Because it messes up the order in which people
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Tue, 01 Nov 2011 23:59:41 +0000
Though the UK is now officially using 230 V phase to neutral, which is 398 phase to phase, so I guess you would call it 230/400. 3 phase is quite unusual for domestic properties in the UK, though I t
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Tue, 29 Nov 2011 23:20:32 +0000
IIRC the dielectric constant of water is about 80, so it is very high compared to most other materials, so there is certainly the potential to increase capacitances quite a bit, but depending on the
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Wed, 30 Nov 2011 21:18:32 +0000
I'd somewhat doubt the tap water would be sufficiently conductive to have a major effect on the DC resistance of a 50 ohm load. If the load was 1 M Ohm, then I see it's possible, but I very much doub
I'm feeling rather tired now, but will do my best to have a go at this. The idea of the transmissioln line is to present an inductive reactance that's equal in magnitude to the output capacitance and
Sorry, I did not finish this before accidently sending. I'll revisit this later for you, but it would help if you post the relevant designs. One parameter you have not given is the height above the c
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Thu, 05 Jan 2012 22:31:50 +0000
The case has quite a major effect if it's distance is not much larger than the spacing between the chassis and the stripline. I'd say if the distance between teh stripline and the side walls of the c
1) Install the tube. 2) Have the power off 3) Put the GDO near the stripline and find the dip. 4) Gradually move the GDO further from the stripline. The dip will get weaker as the GDO is couples less