[time-nuts] Thunderbolt not seeing satellites

Steve steve65 at suddenlink.net
Thu Jun 10 21:56:57 EDT 2010


The voltages I measure are 11.8, -12.3 and 4.9VDC. Those measurements 
are with the unit operating and the power supplies under normal load.

There is 4.7VDC on the feed to the antenna, that is with the coax 
attached to the Thunderbolt.

Arthur's suggestion that something is amiss in the RF section seems 
probable.

Thanks for the thoughts and ideas, anything else to consider?

Steve

On 6/10/2010 8:22 PM, Didier Juges wrote:
> The TB has an error flag if there is no antenna connected (open) or if it is shorted. The tboltmon PC software reports these flags, and so does my GPSMon firmware in the fluke.l monitor.
>
> It is possible but unlikely that there would be something wrong with the bias circuit that would not be reported by the TB.
>
> Didier
>
>
> ------------------------ Sent from my BlackBerry Wireless thingy while I do other things...
>
> -----Original Message-----
> From: Arthur Dent<golgarfrincham at yahoo.com>
> Date: Thu, 10 Jun 2010 15:49:00
> To:<time-nuts at febo.com>
> Subject: [time-nuts] Thunderbolt not seeing satellites
>
>
> It may or may not tell you what's wrong but a quick check of the
> Thunderbolt would be to put a tee in series with the antenna and
> see if the unit is supplying +5 volts under load to the antenna.You
> have verified that the antenna works with a second unit so you can
> rule that out. Where you are getting some data from Lady Heather
> showing it picks up at least 1 satellite I suspect the +5 Vdc power
> supply that supplies the logic is functioning properly or you'd probably
> see no data. The +12 Vdc mainly supplies the oscillator so if that's
> working properly, the +12 is probably ok, It may well be a component
> in the receiver section on the Thunderbolt board.
>
> The Thunderbolt receiver board I looked at had a Macom AM50002 amplifier
> ( http://cs.utsource.net/goods_files/pdf/71/71500_MACOM_AM500002.pdf )
> located on the top side of the board directly behind the antenna connector.
> The bottom side of the board has D1, Q1, and R1 directly behind the 1PPS
> connector and they apparently supply the +5 to power the antenna. Those
> two areas would be likely suspects.
>
>
>
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