Re: Wimo 13cms yagi


DD1US
 

Dear all,

 

I would like to add:

 

Do not use right angle adapters unless they are of proven excellent quality.

 

They can create resonances at 23cm band and higher …

 

Kind regards

 

Matthias

 

www.dd1us.de

 

 

Von: UKMicrowaves@groups.io <UKMicrowaves@groups.io> Im Auftrag von alwyn.seeds1
Gesendet: Samstag, 16. November 2019 11:23
An: UK Microwaves groups.io <UKMicrowaves@groups.io>
Betreff: Re: [UKMicrowaves] Wimo 13cms yagi

 

Dear All,

 

Cable and connectors.

 

I have measured very deep (20dB) suck-outs and corresponding reflection spikes around 2.3GHz on some samples of Ecoflex 15.

 

I have also measured severe suck-outs, but usually above 3 GHz, on poor quality N-Type connectors.

 

Definitely check your cable and connectors carefully, before working on the aerial.

 

Regarding the comment on “Heliax”, I do not agree. 

 

All foamed dielectric solid outer cables that I have seen do not have helical corrugations.

 

I have measured many samples of these cables up to their rated frequencies and above.

 

The large LCF-78 types are rated to 6GHz and have no problems at all at 2.3GHz.

 

The upper frequency limit is normally set by circumferential modes in the cable- the spacing between the corrugations is chosen so that the periodic feedback from these occurs above this frequency.

 

Regards,

 

Alwyn G8DOH

 

 

_____________________________________________________

 

Alwyn Seeds, Director
SynOptika Ltd.,
114 Beaufort Street,
London,
SW3 6BU,
England.


SynOptika Ltd., Registered in England and Wales: No. 04606737
Registered Office: 114 Beaufort Street, London, SW3 6BU, United Kingdom.

_____________________________________________________

 

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