[time-nuts] Active antennas for a Thunderbolt...

[Azelio Boriani]

I use a small power supply to feed the antenna (use a bias tee) and a DC
block for the analyzer input. I have made a quadrifilar helix for the
analyzer output. Set a suitable frequency range (1400-1700) and test. Yes,
I have (at work) an analyzer with the S-parameter test set, so that no
directional coupler and no problems, moreover I have new antennae to test
to make comparisons but the results are clearly visible and you can
recognize a defective antenna. Usually customers send in questionable
antennae and we can tell weather or not they are really unusable: lightning
is the killer.

On Mon, Jul 30, 2012 at 9:54 PM, Chuck Harris <cfharris at erols.com> wrote:

> Hi Azelio,
>
> How would you use a network analyzer to test an active antenna
> like these?  I have the ANA, but I am not sure how to couple
> the input to the antenna effectively.
>
> -Chuck Harris
>
> Azelio Boriani wrote:
>
>> Have you any other GPS unit to test your antennae? You can test GPS
>> antennae with a network analyzer or a spectrum analyzer with the tracking
>> generator... yes, first you have to find one.
>>
>> On Mon, Jul 30, 2012 at 5:12 PM, Hal Murray <hmurray at megapathdsl.net>
>> wrote:
>>
>>
>>> cfharris at erols.com said:
>>>
>>>> I suspect that I have just had the bad luck to buy two bad antennas, but
>>>>
>>> I
>>>
>>>> am naturally curious what happens when the sample set gets larger.
>>>>
>>>
>>> I have 2 TBolts using the small Motorola antenna from TAPR in a not-good
>>> location.  The sheet says 24 dB of gain.  I have 6 or 9 or ?? feet of
>>> RG-6.
>>>
>>> They work as expected, that is they work, but not well.  The holdover
>>> logic
>>> gets tested frequently and surveys take a long time.  But they do work.
>>>
>>> --
>>> These are my opinions.  I hate spam.
>>>
>>
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