[time-nuts] LTE-Lite Antenna

SAIDJACK at aol.com SAIDJACK at aol.com
Sat Nov 22 21:14:17 EST 2014


Hi Jim,
 
not much harm should come to the 5V antenna if driven at only 3.3V.
 
However if you feed 5V into the LTE Lite antenna port then bad things will  
happen because it will back-feed into the 3.3V power rail, and possible 
damage  some of the 3.3V parts on the PCB. Running a 3.3V antenna port with 
external 5V  feeding in is never a good idea..
 
That said you can actually power the unit from 3.3V coming from another  
unit through just the antenna port. Don't ask me how I know..
 
bye,
Said
 
 
In a message dated 11/22/2014 18:09:16 Pacific Standard Time,  
wb4gcs at wb4gcs.org writes:

SAID:
After checking schematics, was contemplating exactly  this.  I wanted to 
make sure I can't do any harm, and it appears  not.
Will probably give it a try tomorrow....
If it doesn't work, I've  come up with a bias-T and amplifier.  Will have 
to spin a PCB,  tho.

Will advise.

Jim

On 11/22/2014 8:46 PM, _SAIDJACK at aol.com_ (mailto:SAIDJACK at aol.com)  wrote:


Jim,
 
try it out. Check the C/No values in the GPGSV NMEA messages. If they  are 
over 40dB, then it works just fine and there is no need to over-think  the 
issue..
 
bye,
Said
 
 
In a message dated 11/22/2014 16:39:55 Pacific Standard Time, 
_kb8tq at n1k.org_ (mailto:kb8tq at n1k.org)  writes:

Hi

Pretty much all of the “timing” GPS antennas want to  see 5V to work 
properly. About the only thing I’ve seen that likes 3.3V  are the modern mag 
mount antennas. 

Bob

> On Nov 22,  2014, at 4:55 PM, Jim Sanford _<wb4gcs at wb4gcs.org>_ 
(mailto:wb4gcs at wb4gcs.org)   wrote:
> 
> All:
> 
> Received my LTE-Lite and  ready to play, EXCEPT, I'm in the basement.
> 
> Does anyone  know if the antenna which the ebay purveyor of the Nortel 
Thunderbolts  supplies will work on the 3.3 volts coming out of the LTE  Lite? 
  (I measured the Nortel, it puts 4.95 volts on the  coax.)  That antenna 
has the advantage of being at altitude with a  feedline run to the basement.
> 
> Thanks,
> Jim
>  _wb4gcs at amsat.org_ (mailto:wb4gcs at amsat.org) 
> 
>  
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