Re: [time-nuts] time-nuts Digest, Vol 159, Issue 14 SDR hacking

2017-10-09 Thread Andre
> On Oct 9, 2017, at 10:20 AM, jimlux wrote: > > I'm trying to come up with a relatively simple scheme to calibrate an HF > antenna array - I've got a bunch of RTL-SDRs operating as a distributed array > spread over a few 10s of meters. > > In terms of frequency, I think

Re: [time-nuts] precision frequency/time/amplitude reference

2017-10-09 Thread jimlux
On 10/9/17 8:02 AM, Bob kb8tq wrote: Hi Pick a couple of local broadcast stations and record them. That will give you a baseline for each of the parameters you are after in real time. They *will* drift. Past that, I’d go with a sweep of each node before installation. That will give you the

Re: [time-nuts] precision frequency/time/amplitude reference

2017-10-09 Thread jimlux
On 10/9/17 8:00 AM, Mattia Rizzi wrote: Hi, I did something similar when I had to deliver synchronization over IEEE 802.15.4-CSS (Chirp spread spectrum). If you have SDR on both ends (TX & RX), you can use complex chirp signals and then cross-correlation at RX. Just be sure that the multi-path

Re: [time-nuts] precision frequency/time/amplitude reference

2017-10-09 Thread jimlux
On 10/9/17 9:58 AM, David Witten wrote: Jim, If I understand what you are attempting (I may well not), you might consider the approach taken here: https://github.com/tejeez/rtl_coherent that is where you have a common clock distributed to the RTLs "A single 28.8 MHz reference clock is

Re: [time-nuts] Novatel Dual frequency GNSS receivers on ebay

2017-10-09 Thread Bob kb8tq
Hi One would *guess* that since it has the 702 antenna on it, it does have L1/L2 firmware enabled in the receiver ( 701 = single L1 band, 702 = L1 / L2, 703 = L1,L2.L5 ). Indeed the hardware spans a wide range of “things” depending on the exact license keys you shoot into it. Buying those

Re: [time-nuts] Novatel Dual frequency GNSS receivers on ebay

2017-10-09 Thread Poul-Henning Kamp
In message <6C47315934DF482EB10A679D10C09093@pc52>, "Tom Van Baak" writes: >I'm guessing this product is >mostly designed for the PN part of PNT (Positioning, Navigation, Timing)? At least with the firmwares I have had a chance to test, that is clearly the case. I don't know if they

Re: [time-nuts] Novatel Dual frequency GNSS receivers on ebay

2017-10-09 Thread Tom Van Baak
Christopher, Thanks for that additional information. Can you (or Gregory) also comment on the external frequency input / output and the 1PPS output of this receiver? A quick look at the om-2128.pdf and om-2129.pdf documents has words like "better than 250 ns accuracy" and "50 ns

Re: [time-nuts] Novatel Dual frequency GNSS receivers on ebay

2017-10-09 Thread Christopher Hoover
I have quite a bit of experience with Novatel hardware include OEM6, CPT and SPAN. CPT is an IMU made by KVH and relabeled by Novatel.The accelerometers are MEMs and the roll rate sensors are FOGs. Pretty old design. Performance is decent (but not auto alignment good).

Re: [time-nuts] precision frequency/time/amplitude reference

2017-10-09 Thread David Witten
Jim, If I understand what you are attempting (I may well not), you might consider the approach taken here: https://github.com/tejeez/rtl_coherent and here: https://github.com/tejeez/rtl_coherent/blob/master/hardware/simple/README.md or order a noise-source and antenna switches from here:

Re: [time-nuts] precision frequency/time/amplitude reference

2017-10-09 Thread Mattia Rizzi
Hi, I did something similar when I had to deliver synchronization over IEEE 802.15.4-CSS (Chirp spread spectrum). If you have SDR on both ends (TX & RX), you can use complex chirp signals and then cross-correlation at RX. Just be sure that the multi-path is not killing you (i.e. the

Re: [time-nuts] precision frequency/time/amplitude reference

2017-10-09 Thread Bob kb8tq
Hi Pick a couple of local broadcast stations and record them. That will give you a baseline for each of the parameters you are after in real time. They *will* drift. Past that, I’d go with a sweep of each node before installation. That will give you the frequency response and (to some

[time-nuts] precision frequency/time/amplitude reference

2017-10-09 Thread jimlux
I'm trying to come up with a relatively simple scheme to calibrate an HF antenna array - I've got a bunch of RTL-SDRs operating as a distributed array spread over a few 10s of meters. The things I want to do are: a) determine the phase/time offset between stations relative to other nodes b)

Re: [time-nuts] PRS10 PRBB Shematics

2017-10-09 Thread Li Ang
Hi Guys I have just bought 2 kinds of PRS10 connectors on taobao.com. (PCB type and cable type, refer to the attached photo). It is about 8$ each(the D-SUB + center RF part). If you are looking for it, I can send you the link off the list. Yours Li Ang / BI7LNQ --