[time-nuts] Thunderbolt - trouble locking with some types of antennas

Arnold Tibus arnold.tibus at gmx.de
Mon Jul 31 15:07:07 EDT 2017


Hello Jerry,
I think the problem is not at the antenna, I consider the 58532A to be a
lot better than these smal patch antennas.
But the point is that modern receivers have a significant better sensivity!
In my opinion, indoor position of any kind of antenna is not a good
solution if you want to get
low jitter results. Indoor antennas do get mostly indirect reception via
reflections oft the
SAT-signals, so even the position indicated is not really precise.
When possible, any antenna should be positioned to get a free view to
the sky 360 deg
and at least about 20 deg in elevation.
My antenna is mounted on the top of the roof outside at the highest
point with abt.
10m coax cable down to my good old thunderbolt providing best reception
possible.

I wish you good luck for your further investigations,

73
Arnold, DK2WT

Am 31.07.2017 um 19:19 schrieb Jerry:
> Due to access problems, I run my Thunderbolt with a Symmetricom 58532A
> antenna placed indoor near a window facing South… can’t get much worse but
> most of the time it will be locked onto 3 or 4 satellites.    I recently
> bought a www.leobodnar.com <http://www.leobodnar.com>  GPSDO for my SDR ham
> radio setup.  I was very surprised to find that this minimalist GPSDO using
> a small patch antenna with internal LNA placed near my window had satellite
> & PPL lock within a few seconds.  It requires 3-4 satellite locks for its
> PPL.  However, when I attached the patch antenna to my Thunderbolt –
> satellite signal strength were zero or minus for all satellites.  The specs
> for the patch antenna are listed below.
>
>  
>
> I would appreciate any advice understanding this behavior.
>
>  
>
> Jerry NY2KW
>
>  
>
> Center Frequency 1575.42MHz±3 MHz
>
> V.S.W.R 1.5:1
>
> Band Width ±5 MHz
>
> Impendence 50 ohm
>
> Peak Gain >3dBic Based on 7×7cm ground plane
>
> Gain Coverage >-4dBic at –90°<0<+90°(over 75% Volume)
>
> Polarization RHCP
>
> LNA/Filter
>
> LNA Gain (Without cable) 28+/-3dB
>
> Noise Figure 1.5dB Typ.
>
> Filter Out Band Attenuation (f° =1575.42MHz)
>
> 7dB Min f0+/-20MHZ
>
> 20dB Min f0+/-50MHZ
>
> 30dB Min f0+/-100MHZ
>
> V.S.W.R <2.0
>
> DC Voltage 2.7V/3.0V/3.3V/5.0V/3.0V to 5.0V/other
>
> DC Current 5mA /11mA/15mA Max
>
>  
>
>  
>
>  
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.




More information about the time-nuts mailing list