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Ian Kenway boosted

My view from the restaurant tonight. It inspired me to order lobster.

Ian Kenway boosted
Ian Kenway boosted

Short video (taken just before midnight from my house at the bottom of the Vigla in Symi). Snow is quite a rarity here!

phidoc.net/misc/vigla_snow_240

Ian Kenway boosted

There has been a lot of discussion lately, much of it just plain incorrect, about the relationship between resonance and antenna efficiency. Many incorrectly claim that resonance has nothing to do with antenna efficiency at all, similarly others incorrectly claim that resonance is a direct indication of efficiency. Neither of these statements is true. The reality is that resonance does have a significant impact on how efficient your antenna is, but the relationship is highly non-linear and depends on many characteristics.

Below I have attached a chart hat plots out the total radiation resistance (R_r) vs the measured input resistance (R_in) of a dipole. Efficiency is just R_r/R_in. In other words an efficient antenna will have 100% of its resistance as radiation resistance, and R_in is **always** larger than R_r (since it is essentially ohmic resistance plus radiation resistance). When these two numbers differ significantly an antenna is inefficient. The source for the chart below is here and it gives much of the math if you want a deeper dive:

nptel.ac.in/content/storage2/c

What is important to note here is that at anti-resonance we see a **huge** R_in value and a small R_r value, this means an anti-resonant antenna will have very high losses. Keep in mind the graph is very hard to read for the values <0.5 in length because the resolution isnt high. But there is significant divergence there as well. Notice at ~5/8ths wavelength antenna would exhibit very significant internal ohmic losses due to heat.

@Electronics

Ian Kenway boosted
Ian Kenway boosted

NCA says end-to-end encryption poses challenge for law enforcers on child abuse | NCA (National Crime Agency) | The Guardian

Typical, if a government wants to bring in an oppressive law that will harm everyone, it couches either in terms of child abuse or terrorism.

Only in the #UK would you have an official government agency called the National Crime Agency. Here we have one which apparently commissions crime.

theguardian.com/uk-news/2022/j

Ian Kenway boosted
Ian Kenway boosted

I dont know who needs to hear this, but Allah is just the arabic word for god. Egyptians speak arabic, so Egyptian christians refer to god as allah. Likewise when most musslims talk about god in english thry refer to him as God not Allah.

This is important to emphasize the fallacy in people claiming that christians and musslims worship different gods, its the same god and the same core is at the center of both religions.

Ian Kenway boosted
Ian Kenway boosted

Tory MPs openly discuss Johnson challenge as mood ‘turns dramatically’ - theguardian.com/politics/2022/ "MPs from across party confident of enough letters to trigger leadership contest after Sue Gray’s report"

Ian Kenway boosted
Ian Kenway boosted
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