Red Wave Radio

Hello,

I am looking for the antenna factors table for a Eaton 94455-1 biconical
antenna (20MHz to 200MHz). Does someone have a calibration table for a
similar antenna around, or a manual for this antenna model ?

More exactly I have found some K factors for it but they seems wrong, except
if I'm wrong with the units somewhere. I have a table with figures ranging
from "47" (65MHz) up to "59" (200MHz). Assuming these figures are in dB/m
this would give a gain of -44dBi at 160MHz (K = 20 log(F in MHz) - G - 29.8
isn't it ?). The result is not reasonnable... and not at all compatible with
the measurements.

Are my K factor figures wrong, or is my calculation wrong somewhere ?

Thanks for your help !
Yours,
Robert

Quote:> Are my K factor figures wrong, or is my calculation
> wrong somewhere ?

The links below lead to the AF values (K) for a self-resonant dipole
in your range of frequencies.   It is possible that they could roughly
apply to your biconical, as it should be somewhat close to resonance
across that band.

The antenna in these links was/is associated with a field intensity
meter used in the VHF FM/TV broadcast bands.

The first link shows the multiplier for the voltage value measured by
the meter, in order to determine the value of the incident field.

http://www.pi-usa.com/pdf/71p-3-5.pdf
http://www.pi-usa.com/pdf/71p-3-7.pdf

RF

Quote:> Hello,

> I am looking for the antenna factors table for a Eaton 94455-1 biconical
> antenna (20MHz to 200MHz). Does someone have a calibration table for a
> similar antenna around, or a manual for this antenna model ?

> More exactly I have found some K factors for it but they seems wrong,
> except if I'm wrong with the units somewhere. I have a table with figures
> ranging from "47" (65MHz) up to "59" (200MHz). Assuming these figures are
> in dB/m this would give a gain of -44dBi at 160MHz (K = 20 log(F in MHz) -
> G - 29.8 isn't it ?). The result is not reasonnable... and not at all
> compatible with the measurements.

> Are my K factor figures wrong, or is my calculation wrong somewhere ?

> Thanks for your help !
> Yours,
> Robert

A quick look on Google turned up at least one company offering to sell the
instruction manual for this antenna.  Might be worth a try.

Fundamentally the value should be close to, but less than a half-wave wire
dipole at the frequency of interest.

Chris

Quote:> Hello,

> I am looking for the antenna factors table for a Eaton 94455-1 biconical
> antenna (20MHz to 200MHz). Does someone have a calibration table for a
> similar antenna around, or a manual for this antenna model ?

> More exactly I have found some K factors for it but they seems wrong, except
> if I'm wrong with the units somewhere. I have a table with figures ranging
> from "47" (65MHz) up to "59" (200MHz). Assuming these figures are in dB/m
> this would give a gain of -44dBi at 160MHz (K = 20 log(F in MHz) - G - 29.8
> isn't it ?). The result is not reasonnable... and not at all compatible with
> the measurements.

> Are my K factor figures wrong, or is my calculation wrong somewhere ?

> Thanks for your help !
> Yours,
> Robert

Hello Robert,

AF (K) for Eaton 94455-1 as a receive antenna:

30,  13.7
40, 13.5
50, 12.4
70, 7.7
100, 10.2
140, 16.0
160, 17.5
200, 12.5
Frequency in MHz, K in dB/m.

I don't have the manual, values are from a report, original source
unknown. It would be nice when somebody could confirm these values.

Hope this helps you a bit.

Best regards,

Wim
PA3DJS
www.tetech.nl
when you remove abc, the address is OK.

It's been a long time since I've done field strength measurements, but I
recall that each antenna came with a calibration chart for that
particular antenna -- that's really what you're paying for when you buy
one. I wouldn't expect a great deal of difference from one to another,
but don't have the experience to say how much variation you might expect.

Roy Lewallen, W7EL

http://www.ets-lindgren.com/page/charts.cfm?i=3104C
Has typical cal charts for 3104C biconical.  The
actual antennas are individually calibrated.  The
antenna factors are not that far from Wim's example
above.

Frank

Many thanks Tim, that's exactly what I was looking for !
Robert

Thanks to all for your answers, all figures converge and seems to give an
approximate gain of 0dBi around 160MHz, consistent with our measurements.
Many thanks again !
Robert

Unity?