[time-nuts] TrueTime A-60FS antenna Data Needed

Doug Millar dougnhelen at moonlink.net
Fri Jan 5 23:41:38 UTC 2007


Hi Norman,
         Thanks for you very complete check out information. It 
worked!  The antenna is an active type with a preamp. I also hooked 
it up to a VLF receiver and found it receives very well from near DC 
to 100khz. No obvious peak at 60khz.
         Thanks again,
                 Doug K6JEY



At 03:08 PM 1/5/2007, Normand Martel wrote:
>You could do a simple test:
>
>With an ohmmeter, on Diode test and with reversed
>polarity (Red on shield, black on center pin), measure
>the DC resistance on the RF connector. If it's a short
>(< 1 ohm) DO NOT APPLY ANY VOLTAGE ON IT! Your antenna
>is passive and conducting.
>
>If the ohmmeter indicates a diode reading (about 0.7V)
>the antenna is active and some bias will be required
>to have the antenna work.
>
>If the reading is infinite, it is either a passive
>(open) or active antenna.
>
>To further determine the type of antenna, i suggest
>you to use some length of coax (20-50ft) cable to put
>the antenna away from you, and, using a regulated 5
>volts power supply with a 1000 ohms SERIES resistor,
>apply power (forward polarity, e.g. positive on center
>pin) to the antenna and measure the voltage across the
>1000 ohm resistor.
>
>If you have some voltage across the resistor, this
>indicates that the antenna preamplifier draws some
>current and, obviously, the antenna is active. If no
>voltage is present across the 1000 ohms resistor,
>your antenna is passive.
>
>Why the 20-50 foot coax? Simply to put some isolation
>between you and the antenna. If the preamplifier is
>turned on by the 1000 ohms bias and the antenna is too
>close from you, the whole thing will start to
>oscillate.
>
>73 de Normand VE2UM
>
>--- Doug Millar <dougnhelen at moonlink.net> wrote:
>
> >
> > Hello,
> >       Hope the New Year is going well. I recently got the
> > above antenna to
> > use on another receiver, but no data. Does anyone
> > have a description
> > of the interface? Is it just a simple ferrite
> > antenna, or does it
> > have a preamp and need bias, or "other" ?  Any info
> > would be very helpful.
> >       Thanks,
> >       Doug K6JEY
> >
> >
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