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Comment Re:Counterpoise (Score 1) 76

That is a good point, but I'm not sure how well it would work over standard fractional wavelength radials on larger systems. The Marconi drawing has lighting and static charge protection from the grounded side of the voltage transformer that's being fed from the transmitter. It could be very useful for space conscious form factors, and I don't know anyone that wants a radial and whip system for a cell phone.

From Marconi's drawing, it looks more like use of a coil as either a resonant stub or shorted stub being directly fed to a phasing coil that is being fed from a voltage balun from the tank oscillator. It's a little different than traditional ones since it's wound into a coil, though.

Since shorted stub filters are inductive in nature, they typically broaden the bandwidth of the capacitive mono-pole element. Those are pretty interesting microwave tricks, but winding a stub into a coil may reduce material and size requirements where space is at a premium. It's probably a sacrifice on bandwidth of the system with the tradeoff that the stub would probably contain the RF to the center of the inductor. Maybe there's something more I'm missing here.

Well, beyond the theory, it kinda looks like a curly-que J-pole to me

Comment Re:My B.S. Detector is Going Off (Score 1) 76

Exactly. That's a multiband antenna system. Change bands, change the tap point. The point they're missing is grounding of the "asymmetric" half of the antenna, and that's to keep a static charge from building in the antenna that'll zap through your electronics (or you) for safety reasons. The center tapped grounded coil feedpoint matching is also less noisy than an inline tuning coil.

Comment Re:Run your own equipment (Score 2) 96

Unfortunately, that's not entirely true with cable modems. Connecting to the DOCSIS network grants your ISP admin rights over the device. That's a big reason why you should separate the functionality of your primary gateway route from your DOCSIS demarcation device.

Comment Run your own equipment (Score 5, Informative) 96

I've always run my own hardwsare for years for a reason: it gives me a buffer beyond which I know the ISP no longer has control of my home network. 2x OpenWRT routers, a managed switch in the middle, and a lightweight embedded PC running the essential network services (dhcp, dns, ntp, etc), and the IT management overhead is fairly low.

Comment Re:Article is wrong. Transceivers do this already. (Score 3, Informative) 47

The issue is that a strong transmission in the same band as a receiver can desense the receiver. This can also be done with a cavity duplexer if you need input and output in the same band on adjacent frequencies, but you pay for it with geometric space (since cavity duplexer dimensions are a fraction of the wavelength in free space multiplied by the materials velocity factor). This can be problematic on HF and VHF bands, but UHF and microwave can get away with duplexers the size of a brick. Unfortunately, that's still too much for mobile phones since it's too big to fit in someone's pocket.

Comment Re:Have you heard of routing protocols? (Score 1) 80

Indeed, I have many times run a linux router by doing nothing but installing quagga, Net-SNMP, ipt_netflow, and I've got a lower end equivalent to some of the highest end commercial networking equipment.

Both OSPF and BGP provide the tools you need for policy based routing to various degrees, and quagga gives you that. The rest is just icing on the cake.

Comment Re:ASN.1/SMI (Score 1) 242

Ah, script tags... I agree with you completely. Programming languages merely describe a format electronic data format that can be read in by a computer program or piece of hardware affecting the state of the system in some way. They do not necessarily need to contain procedural instructions, and the definition of turing complete simply determines whether that particularly language is description enough to implement general purpose algorithms. Also, a lot of computer security issues come up from these non-TC programming languages being fed into a system and running instructions anyway.

As a theoretical example, someone's web server delivers a malicious image file that crashes the client image codec library and fools it into running code contains elsewhere in the malicious file. Doesn't matter whether that image was designed to contain procedural instructions or not if someone can fool the parser to run those instructions anyway.

Comment Re:ASN.1/SMI (Score 2, Informative) 242

They are not turing complete programming languages, but they are domain specific programming languages. This is the same as making the argument that SQL is not a programming language since you only use it to define/insert/update/delete data in a database and cannot write general purpose programs without another tool that does provide a turing complete function set. ASN.1 and SMI are formats to describe messages and message data types to be used by another higher level protocol like SNMP, LDAP, X.509, etc.

Comment Re:Embedded Systems (Score 4, Insightful) 641

I agree with PP and GP, but there's more to it than just that. Software is like an organ of your computer; your computer typically won't do much worthwhile if there's not a whole bunch of the things working together to make complete systems. Almost every one of the higher level languages are implemented in C at some point in the software stack. Some might argue that certain JVM languages like Scala and Groovy and Clojure are written in pure java, but guess what? The JVM is written in C. Almost every piece of software out in the wild is either written in C or depends on critical components written in C all the way down to the operating system. If you're running embedded, you might not have an OS, but you probably should be using C on microcontrollers and embedded systems unless there's a real good reason not to.

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