Welcome to the new FlexRadio Community! Please review the new Community Rules and other important new Community information on the Message Board.
Need the latest SmartSDR, Power Genius, Tuner Genius and Antenna Genius Software?
SmartSDR v3.7.4 and the SmartSDR v3.7.4 Release Notes | SmartSDR v2.12.1 and the SmartSDR v2.12.1 Release Notes
SmartSDR v1.12.1 and the SmartSDR v1.12.1 Release Notes
Power Genius XL Utility v3.8.8 and the Power Genius XL Release Notes v3.8.8
Tuner Genius XL Utility v1.2.11 and the Tuner Genius XL Release Notes v1.2.11
Antenna Genius Utility v4.1.8
SmartSDR v3.7.4 and the SmartSDR v3.7.4 Release Notes | SmartSDR v2.12.1 and the SmartSDR v2.12.1 Release Notes
SmartSDR v1.12.1 and the SmartSDR v1.12.1 Release Notes
Power Genius XL Utility v3.8.8 and the Power Genius XL Release Notes v3.8.8
Tuner Genius XL Utility v1.2.11 and the Tuner Genius XL Release Notes v1.2.11
Antenna Genius Utility v4.1.8
If you are having a problem, please refer to the product documentation or check the Help Center for known solutions.
Need technical support from FlexRadio? It's as simple as Creating a HelpDesk ticket.
Need technical support from FlexRadio? It's as simple as Creating a HelpDesk ticket.
Using GPS 10.00000Mc Output for Frequency Measuring Test (FMT)
Options
k3Tim
Member ✭✭✭
How effective would it be to use the 10.000Mc GPS signal from the 6500 / 6700 (assuming the optional accesory is installed) in the following manner?
Using FLDIGI one has to calibrate the PC and a procedure to do so has been published. A variant method follows:
Feed the GPS-10.0Mc output into one of the antenna ports and adjusted FLDIGI audio offset with LSB tuned to 10.001. This results in a 1.00Kc tone to FLDIGI. Use this to calibrate the entire received system (DaX, PC etc) with highest frequency accuracy possible. The assumption is the GPS signal is much more stable / accurate wrt frequency than WWV over HF would be.
Once calibrated, to perform FMT, a slice / DaX / FLDIGI instance would be set to the test frequency in the normal method. A second slice / DaX / FLDIGI instance would be tuned to the GPS reference to track drift in the local system.
After the test, the two frequency measurements are "combined" to remove the drift from the PC side. Admittedly, "combined" is some hand waving at this point and perhaps the PC doesn't drift enough in the short term to be a concern - not sure. Granted also this is really splitting hairs - or more like a sub-Hz measurement.
Comments?
_..--
K3Tim
Using FLDIGI one has to calibrate the PC and a procedure to do so has been published. A variant method follows:
Feed the GPS-10.0Mc output into one of the antenna ports and adjusted FLDIGI audio offset with LSB tuned to 10.001. This results in a 1.00Kc tone to FLDIGI. Use this to calibrate the entire received system (DaX, PC etc) with highest frequency accuracy possible. The assumption is the GPS signal is much more stable / accurate wrt frequency than WWV over HF would be.
Once calibrated, to perform FMT, a slice / DaX / FLDIGI instance would be set to the test frequency in the normal method. A second slice / DaX / FLDIGI instance would be tuned to the GPS reference to track drift in the local system.
After the test, the two frequency measurements are "combined" to remove the drift from the PC side. Admittedly, "combined" is some hand waving at this point and perhaps the PC doesn't drift enough in the short term to be a concern - not sure. Granted also this is really splitting hairs - or more like a sub-Hz measurement.
Comments?
_..--
K3Tim
0
Answers
-
14.995 Mhz test calibration for all digi mod
elan g0uut0 -
I think the calibration routine is for the soundcard. Since you are not really using a soundcard, is it even necessary to calibrate the PC?
0 -
Hi Neal,
This is a good point. The signal to the PC is digital so the PC itself shouldn't need calibration. I believe the GPS disciplines the main oscillator in the Flex but I am not sure if this reaches the DSP / ARM clock domains. If these are from an internal crystal then a calibration run would be required.
When calibrating FLDIGI it appears an offset was required.
I'll try the GPS - 10Mc signal with no offset and check the FLDIGI results; will report back.
Thanks for your excellent point...
k3Tim0 -
Follow up: Tested using the GPS out, luckily reading the manual and see the output signal as a 3.3 V level! Used an attenuator of 40 dB although more would have been preferred. The GPS signal was observed on the FLDIGI "output scope" to be an ultra stable flat line. A Rx offset (-38) was required to place this flat line on zero axis. This would seem an easier method to tune the offset setting than over the air signals. The offset matched the over the air setting.
Since the signal shown on the frequency measurement window was so stable, confirming the "audio soundcard" in the system (flex and PC side) are stable there is no reason to use the GPS signal to check for drift during an FMT.1 -
I was actually thinking on using the GPS out signal to correct all my other radios. The 1500 has a 10Mhz IF input and there is a part you can get here http://www.vk3hz.net/XRef/XRef_Home.html to input a 10 MHz reference signal from a GPS reference into an FT857/897, TS2000, IC-706MkIIG, IC-910H, IC-9100 and FT-847. That together with a signal hub and I can use the GPS reference of the 6700 on all the other radios.... Right?0
-
From what I read it looks like that part should work with the 6k GPS out. It accepts up to 3.6V input and the signal out of the 6K is 3.3 V. That is an interesting device and I may use on in a TT Omni 6 that I have. The TT needs a 20.0Mc reference and suspect this could be custom ordered.
Thank you for the link.
_..--
Tim0 -
I will add another piece I have also on the list for this, a 10Mhz reference signal distribution hub.
http://www.downeastmicrowave.com/product-p/10-4.htm
Take the 10 Mhz signal from the 6500-6700 into this device and distribute among the other devices. making sure to use 50 Ohms terminations if not using the port.1
Leave a Comment
Categories
- All Categories
- 246 Community Topics
- 2.1K New Ideas
- 488 The Flea Market
- 7.1K Software
- 5.9K SmartSDR for Windows
- 134 SmartSDR for Maestro and M models
- 331 SmartSDR for Mac
- 243 SmartSDR for iOS
- 222 SmartSDR CAT
- 163 DAX
- 348 SmartSDR API
- 8.6K Radios and Accessories
- 6.9K FLEX-6000 Signature Series
- 766 Maestro
- 41 FlexControl
- 836 FLEX Series (Legacy) Radios
- 733 Genius Products
- 393 Power Genius XL Amplifier
- 255 Tuner Genius XL
- 85 Antenna Genius
- 229 Shack Infrastructure
- 153 Networking
- 370 Remote Operation (SmartLink)
- 120 Contesting
- 583 Peripherals & Station Integration
- 115 Amateur Radio Interests
- 812 Third-Party Software