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Some of those involved tried changing details of the incident to avoid excessive embarrassment to those affected. ;-) The Rapier involved was operating test software and worked rather better than we they expected it to. To be fair I had worked on the DN181 radar and jumped at the chance to fly...

My personal experience with the S270C on airband is that it is “ok” when near the airfield but not much use elsewhere, unless you can get up very high. For 2/70, for which it is designed, it’s not bad although especially on 2m it’s not brilliant. I wouldn’t necessarely say it “sucks” but, much...

Ah, I believe their systems use a wide range of frequencies but I would suggest that HF (ie: below 30 MHz) radar installed on aircraft is rather unlikely as the antenna arrays would be a significant size and not practical to install on an aircraft smaller than a Zeppelin! Regarding names of...

This is not entirely correct. Most military aircraft, and US aircraft are no different in this, carry more than one active radar system. They may well not be active at all times but they certainly carry them; target acquisition and tracking, terrain, altimeters and other systems all operate...

This is one of the fun things about antennas, in that there are a number of characteristics which all affect the performance in different ways. A large antenna of the wrong length, but ok-ish matched, can work well. A small antenna may be much less efficient in general but when well-matched can...

For reference, a 5 m roll of 1.8 mm nitinol wire is about £30/$37 and will make lots of antennas.

That would be a fine approach for experimenting, although I would still make my own final size one as the telescopic antenna is easy to damage while waving it about running across an airfield...

The Signal Stick probably is a little better than the supplied S270C because its bandwidth is a little wider although not by much. If there is a specific band you're looking to monitor then it shouldn't be hard to make an antenna up yourself, especially if you have access to an antenna anlyser...

Which SignalStick are you going for? This is the return loss plot for the 2/70 dual band version... From this unit, the return loss for WX channels will be around 6 dB, so around a VSWR of 3:1. I guess what I'm getting at is that a properly designed and tuned antenna for the band you are...

Here we go, I knew I had the plots somewhere...please note that the dates on the plots are likely incorrect as I often don't bother to set the analyser clock up! I have included a return loss plot for the R30 supplied antenna (fully extended) as an indication...it is very much better on VHF...

It depends completely on what you want to use it for. If you are looking to receive aero radio then the supplied antenna for the R15 won’t do very well. It is no surprised that for air band the A25 antenna will do much better since it is specifically designed for that band. The supplied 270C...

Of course.

I believe the supplied antenna is the FA-S270C so will be pretty decent for 2 m and 70 cm but likely not great elsewhere. That said, that antenna is pretty inefficient at 2m. I should get hold of an R15 in the next couple of weeks so I can put it on the test bench.

The supply only has to provide 24 V between + and - and the isolation between chassis ground and - has to be high, usually more than 50 MOhm so floating/split supplies are not an issue in and of themselves. Each unit in the system is connected via a CANbus backbone and so floats on the signal...

I cannot answer the first question without more information but I would expect it is probably power supply related, especially given your question number three. Question two suggests that you have batteries being floated by the main and/or backup supply. Question three suggests the supply...

Indeed this is true, however GMDSS power supplies are often configured in this way. Sometimes it is to support two-phase generators with standby and backup battery sources and sometimes it is because the main and standby power are commutated battery sets. Not all systems which are supposed to...

8.33kHz channels do indeed cause a lot of confusion, especially around how they are specified over the air and on the radios. For example Tower telling you “129.400“ means a frequency of 129.400 MHz with a channel step/width of 25 kHz. Tower telling you “129.405” means the same frequency but in...

So if you want to know how I made these measurements you need to understand a little about how the handheld is designed to operate. Firstly, a handheld needs to work properly when either hand held, so capacitively coupled to a big bag of salty water (the operator!), or standing on a desk or...

So the reason for this type of push-pull power supply is that they are usually designed to operate from shore power, onboard generators and batteries and this arrangement makes the automatic changeover without any switching necessary, making the supply seamless. The incoming shore supply may be...

You can skim past the maths and leave it for later on but the descriptions and explanations are very useful in this context.