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Rg174 should have less than 2dB attenuation for shortwave

Freq?

There isn't much material in this build that is likely to add loss(at this frequency) to the antenna, so in this case, I would expect S11 to be a fairly good proxy for the true performance.

Hi Mike, Great writeup. I haven't seen this style of antenna before. It's a very interesting design. The only thing missing from your blog is any final measurements of the antenna performance. The frequency is right in the sweet spot for a £50 nanoVNA. The S11(vswr) will give you an excellent idea o...

Hi It's difficult to know the exact length to tune a telescopic antenna. The cable and ground plane play a big part. 1/4 wavelength is a good start point. Unless you have a VNA, you can just tweak for optimal reception. It all depends on how critical it is to extract those last few dBs of sensitivit...

Is this an antenna array? For DF for instance.

Or do you just need multiple channels that don't need to be coherent? Kerberos would seem like overkill.

Dipoles would work fine. Or you could have a sleeve dipole, if you only want the antenna to protrude out in one direction(to avoid snarling up on landing for example). One thing worth thinking about for use with Kerberos is that you need to have the antenna well isolated from the cable. That is, you...

Can you elucidate on 'airborne platform'? Is this a fighter jet, microlight or a hot air balloon for example? Where on the platform do you envisage placing the antennas?

I sell some ultra wide band antennas that cover a whole variety of interesting frequencies. I think they are a good start for exploring a while range of bands, but if you have any specific target applications you will probably be able to find a better narrow band antenna. https://www.tindie.com/stor...

All seem reasonable to me. I'm sure there lots of other info people could volunteer too. Just telling us the frequency ( in Hz) is a big help. Don't make us research that esoteric signal that may even be specific to your country. Cable lengths and types used is also worth knowing. What type(RG numbe...