[time-nuts] LTE-Lite Antenna

Bob Camp kb8tq at n1k.org
Sat Nov 22 21:20:44 EST 2014


Hi
> On Nov 22, 2014, at 9:14 PM, S. Jackson via time-nuts <time-nuts at febo.com> wrote:
> 
> 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..

I wonder how well that works with an OCXO based unit…..

Bob

> 
> 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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