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

Hi Jim, On 08/02/2017 03:04 PM, jimlux wrote: On 8/2/17 5:16 AM, Magnus Danielson wrote: BTW, I saw that the JPL receiver at ISS got upgraded to support Galileo. Cool stuff. well, not exactly upgraded - the hardware didn't change - being bolted to the exterior of ISS inside a box inside

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

On 8/2/17 5:16 AM, Magnus Danielson wrote: BTW, I saw that the JPL receiver at ISS got upgraded to support Galileo. Cool stuff. well, not exactly upgraded - the hardware didn't change - being bolted to the exterior of ISS inside a box inside a box - it was a software change - which is

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

On 08/02/2017 01:20 AM, jimlux wrote: On 8/1/17 12:11 PM, Graham / KE9H wrote: Dider: This is a CDMA signal. (With a 'chip' rate that far exceeds the information rate.) If you put a different correlator on every multipath signal, which are each differently delayed in time, then they can be

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

On 8/1/17 12:11 PM, Graham / KE9H wrote: Dider: This is a CDMA signal. (With a 'chip' rate that far exceeds the information rate.) If you put a different correlator on every multipath signal, which are each differently delayed in time, then they can be independently demodulated. (Or time

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

On 8/1/17 11:11 AM, Didier Juges wrote: "The newer the receiver, the more horsepower in the silicon. In the case of GPS, that gives you more correlators to do DSP. The sensitivity improvement is a direct result of that. If you take a look at the guts of a TBolt, they date to the late 1990’s.

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

" having around 20 dB of gain at the antenna greatly decreases the effect of feed line loss on noise figure." And that would be consistent with usage for a timing receiver which is expected to have a well exposed antenna and a significant line length, as opposed to navigation receivers where the

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

Dider: This is a CDMA signal. (With a 'chip' rate that far exceeds the information rate.) If you put a different correlator on every multipath signal, which are each differently delayed in time, then they can be independently demodulated. (Or time shifted and added back together with some

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

"The newer the receiver, the more horsepower in the silicon. In the case of GPS, that gives you more correlators to do DSP. The sensitivity improvement is a direct result of that. If you take a look at the guts of a TBolt, they date to the late 1990’s. That’s a long time in silicon years …." It

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

Hi Jerry: The Trimble is the oldest mass produced GPS receiver I know of and because the early receivers used high gain antennas it seems that Trimble kept that idea for the newer designs. They like about 41 dB gain between the antenna and the input to the receiver.

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

Hi > On Jul 31, 2017, at 3:32 PM, Didier Juges wrote: > > The Thunderbolt is well known for not having the best sensitivity among GPS > receivers. It seems that timing receivers in general, particularly those of > the same generation as the Thunderbolt are not as sensitive

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

The Thunderbolt is well known for not having the best sensitivity among GPS receivers. It seems that timing receivers in general, particularly those of the same generation as the Thunderbolt are not as sensitive as navigation (possibly newer) GPS receivers. It may be because they are expected to

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

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

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

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 GPSDO for my SDR ham