[time-nuts] Re: GPS antenna locations

[N1BUG]

On 4/17/22 13:08, Bob kb8tq wrote:
> The TBolt needs about 16 db in front of it to do a reasonable job. With a
> 30 db gain antenna and no splitters, that leaves you with about 14 db or
> so for cable and connector loss. Most of us accumulate multiple GPS
> gizmos. A 4 way splitter takes your 14 down to 8 db. That puts you “at
> the limit” with a bit over 100’ of LMR-400.

I currently have three GPS gizmos and expect to hold at that number. I 
use a GPS Networking LNFA1X4-N filtered amplified splitter spec'd at 0 
dB gain/loss. With the side mount option, the worst case cable loss 
would be around 10 dB, but probably a few dB less. It depends on which 
available cable I use.

> The filter is after the amplifier. However the antenna itself is pretty narrowband.
> If the filter was in front, getting a 2 db noise figure would be exciting.

Well then, possibly a concern but I suspect a GPS antenna doesn't pick 
up RF below 500 MHz very efficiently. I guess the only way to know for 
certain is to try it.

Paul