Whatever's this? Strange 'radio aerial'?

[Synchrodyne]

Originally Posted by G8HQP Dave

It is precisely under the conditions of antenna length being a small fraction of a wavelength where a capacity hat (however small) is helpful. Not very helpful, mind you. Perhaps unmeasurably so, but theoretically helpful. It slightly lowers the impedance of the antenna, so slightly increases the delivered signal into any typical (lower) receiver input impedance.!

That being the case, then perhaps Antiference might well have claimed that the TV aerial portion was acting as a capacity hat for the radio portion of its combined TV and antistatic radio aerial system pictured in the attachment. Given that the vertical was only 10 ft, as compared with the 15 or 20 ft normal for AM vertical whips, it probably needed all the help it could get. Possibly the capacity hat effect would have been greater in cases where the TV aerial was set for horizontal polarization.

Antiference did claim that both the vertical pole and the TV aerial spreader bar functioned as the radio aerial, so the mention of the (horizontal) spreader bar implies a claim for the capacity hat benefit, however small it might have been.

If the Aerialite thought that its Anomast did provide some benefit, then one may wonder why it did not offer it as an option for mounting upon the top of its vertcial antistatic aerials, although I guess that would have been rather awkward in a mechanical sense.

Cheers,

[SiriusHardware]

I would say the 'modern' concept equivalent of these are those 'Hi-Gain' TV set-top aerials with two telescopic rods (the actual aerial) and a mini plastic satellite dish mounted between them...

[hansomcommon]

The unit shown in the first picture is called "R.W. Non Directional Aerial" made in 1935 by The Concordia electric wire co. ltd, New Sawley Nr Nottingham. It sold for a fixed price of 4/9.

Here is the original advert

[Phil G4SPZ]

Thanks for that. I think you are absolutely correct. The Anomast looks similar but this is bang on.

I'm also grateful for the date.

[hansomcommon]

They are certainly long lived, I have one on the top ridge of my roof, it is used as a capacity hat for my pantry transmitter.