Re: [amsat-bb] Leo Bodnar ICOM IC-9700 Reference Injection Board
I was wondering what the advantage is for using this board vs the standard 10Mhz external reference on the 9700?
73 Eric WD8KNL
Hi Eric, mobile so brief. Better stability over time and temps. It’s not essential, just desirable for some. The 10 MHz injection on a stock radio doesn’t do what you might expect, based on other Icom radios. Best advice is for interested people to read the traffic in the groups.io 9700 group! There is another option soon as well, but there are tradeoffs.
Mark N8MH
On Sat, Feb 15, 2020 at 8:14 AM kd8drg.admin--- via AMSAT-BB < [email protected]> wrote:
I was wondering what the advantage is for using this board vs the standard 10Mhz external reference on the 9700?
73 Eric WD8KNL _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Eric,
I found much information on the design and benefits of a GPSDO and reference board for the IC-9700 here:
https://www.minikits.com.au/gps9700#wspr
The Mini-Kits version is only slightly different than the Leo Bodnar version however the designs are virtually identical.
http://www.leobodnar.com/shop/index.php?main_page=product_info&products_... http://www.leobodnar.com/shop/index.php?main_page=product_info&products_...
Bob W7OTJ
On Sat, Feb 15, 2020 at 8:16 AM kd8drg.admin--- via AMSAT-BB < [email protected]> wrote:
I was wondering what the advantage is for using this board vs the standard 10Mhz external reference on the 9700?
73 Eric WD8KNL _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
This is a good explanation:
"With the current firmware, users have observed frequency drift when using narrow bandwidth modes. Using an external 10 MHz and the firmware reduces the size of the frequency drifts by updating the corrections to the master oscillator more frequently. The drift is still there,,,,, With the 49.152 MHz injector board and a good external 49.152 MHz GPS-locked oscillator, the external oscillator locks the internal oscillator and the drift issue is eliminated. The drift is probably not important on FM and most may not notice the issue on SSB. But it is important to eliminate the drift if you are using JT65 and similar narrow bandwidth modes."
Copied from the Facebook ic-9700 group and a post by Peter Freeman in reply to Tim Goodrich's question: https://www.facebook.com/groups/163460540873662/
Bob W7OTJ
On Sat, Feb 15, 2020 at 1:53 PM Bob Hammond [email protected] wrote:
Eric,
I found much information on the design and benefits of a GPSDO and reference board for the IC-9700 here:
https://www.minikits.com.au/gps9700#wspr
The Mini-Kits version is only slightly different than the Leo Bodnar version however the designs are virtually identical.
http://www.leobodnar.com/shop/index.php?main_page=product_info&products_...
http://www.leobodnar.com/shop/index.php?main_page=product_info&products_...
Bob W7OTJ
On Sat, Feb 15, 2020 at 8:16 AM kd8drg.admin--- via AMSAT-BB < [email protected]> wrote:
I was wondering what the advantage is for using this board vs the standard 10Mhz external reference on the 9700?
73 Eric WD8KNL _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
I wonder if anyone who has all the needed equipment to test has verified that the output of the 9700 is still clean after this mod?
In the past ext reflock boards compared the radios osc to a gps locked 10mhz signal and adjusted the trim voltage going to the vctcxo so levels were not touched, the radio was as clean or dirty as it was when it left the factory. Now with this mod (if I understand it correctly) the main osc is still running and they are just pumping a much stronger signal into the master osc area until it drowns out the original osc and the radio locks to it. So the question comes up are they then overdriving the osc chain downline and distorting? and is the original osc signal still there in the background now as noise?
Might be a interesting project to find out.
73 Kevin wa7fwf
On 2/15/2020 14:08, Bob Hammond via AMSAT-BB wrote:
This is a good explanation:
"With the current firmware, users have observed frequency drift when using narrow bandwidth modes. Using an external 10 MHz and the firmware reduces the size of the frequency drifts by updating the corrections to the master oscillator more frequently. The drift is still there,,,,, With the 49.152 MHz injector board and a good external 49.152 MHz GPS-locked oscillator, the external oscillator locks the internal oscillator and the drift issue is eliminated. The drift is probably not important on FM and most may not notice the issue on SSB. But it is important to eliminate the drift if you are using JT65 and similar narrow bandwidth modes."
Copied from the Facebook ic-9700 group and a post by Peter Freeman in reply to Tim Goodrich's question: https://www.facebook.com/groups/163460540873662/
Bob W7OTJ
On Sat, Feb 15, 2020 at 1:53 PM Bob Hammond [email protected] wrote:
Eric,
I found much information on the design and benefits of a GPSDO and reference board for the IC-9700 here:
https://www.minikits.com.au/gps9700#wspr
The Mini-Kits version is only slightly different than the Leo Bodnar version however the designs are virtually identical.
http://www.leobodnar.com/shop/index.php?main_page=product_info&products_...
http://www.leobodnar.com/shop/index.php?main_page=product_info&products_...
Bob W7OTJ
On Sat, Feb 15, 2020 at 8:16 AM kd8drg.admin--- via AMSAT-BB < [email protected]> wrote:
I was wondering what the advantage is for using this board vs the standard 10Mhz external reference on the 9700?
73 Eric WD8KNL _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
In short, yes.
I have performed phase noise measurements on my IC-9700, with and without injection locking. I am currently using a Leo Bodnar Mini GPSDO as the reference, though using a MiniKits injection board (Leo wasn't selling his at the time). I had to do this kind of locking as there was noticeable drift when attempting 70cm EME contacts with the IC-9700 unlocked, which was causing degradation in decode performance. With the radio locked there are no issues.
The test equipment was a Symmetricom 5125A Phase Noise Test Set, and I was using a 160 MHz Wenzel as a reference. The 5125A only works on input signals up to 400 MHz, so for 70cm and 23cm I mixed the signal down to ~30 MHz using a Minicircuits LAVI-2VH, with the LO generated by a R&S SMA100B. The rig was powered from 2x 100Ah batteries, and the GPSDOs were powered from a 5V linear bench supply.
I tested: - (2m/70cm/23cm) Unlocked IC-9700, transmitting for ~5 minutes to let the drift settle as best as it can. - (2m/70cm) IC-9700 + MiniKits Coupler board, driven with the MiniKits GPS-9700 (+10 dBm) - (2m/70cm/23cm) IC-9700 + MiniKits Coupler board, driven with a Leo Bodnar Mini GPSDO (maximum drive, which is ~+10 dBm I believe) - (2m only) IC-9700 + MiniKits Coupler board, driven with the R&S SMA100B (+10 dBm)
Plots of the results are here: https://imgur.com/a/iFi527l
I guess the key point is that there is no degradation of transmit phase noise observed when using any of the injection locking solutions. While I did previously see some wide-band phase noise differences between the MiniKits and Leo Bodnar LO's (as measured at 49.152 MHz), this doesn't translate to a degradation at the output of the transmitter. I'm not seeing the wide-band noise improvements when injection locked that others have seen.
There appears to be a slight improvement in close-in phase noise when injection locked with the GPS-9700 and Mini-GPSDO (and a big improvement when using the SMA100B, but that sig-gen costs 20x more than the rig does), but I wouldn't read too much into the close-in results as I only had time to run each measurement for ~5 minutes or so. However, note that the test-set noise floor (shaded area) is *well* below the measured results.
73 Mark VK5QI
On Sun, Feb 16, 2020 at 9:28 AM Kevin via AMSAT-BB [email protected] wrote:
I wonder if anyone who has all the needed equipment to test has verified that the output of the 9700 is still clean after this mod?
In the past ext reflock boards compared the radios osc to a gpslocked 10mhz signal and adjusted the trim voltage going to the vctcxo so levels were not touched, the radio was as clean or dirty as it was when it left the factory. Now with this mod (if I understand it correctly) the main osc is still running and they are just pumping a much stronger signal into the master osc area until it drowns out the original osc and the radio locks to it. So the question comes up are they then overdriving the osc chain downline and distorting? and is the original osc signal still there in the background now as noise?
Might be a interesting project to find out.
73 Kevin wa7fwf
On 2/15/2020 14:08, Bob Hammond via AMSAT-BB wrote:
This is a good explanation:
"With the current firmware, users have observed frequency drift when
using
narrow bandwidth modes. Using an external 10 MHz and the firmware reduces the size of the frequency drifts by updating the corrections to the
master
oscillator more frequently. The drift is still there,,,,, With the 49.152 MHz injector board and a good external 49.152 MHz GPS-locked oscillator, the external oscillator locks the internal oscillator and the drift issue is eliminated. The drift is probably not important on FM and most may not notice the issue on SSB. But it is important to eliminate the drift if
you
are using JT65 and similar narrow bandwidth modes."
Copied from the Facebook ic-9700 group and a post by Peter Freeman in
reply
to Tim Goodrich's question: https://www.facebook.com/groups/163460540873662/
Bob W7OTJ
On Sat, Feb 15, 2020 at 1:53 PM Bob Hammond [email protected]
wrote:
Eric,
I found much information on the design and benefits of a GPSDO and reference board for the IC-9700 here:
https://www.minikits.com.au/gps9700#wspr
The Mini-Kits version is only slightly different than the Leo Bodnar version however the designs are virtually identical.
http://www.leobodnar.com/shop/index.php?main_page=product_info&products_...
http://www.leobodnar.com/shop/index.php?main_page=product_info&products_...
Bob W7OTJ
On Sat, Feb 15, 2020 at 8:16 AM kd8drg.admin--- via AMSAT-BB < [email protected]> wrote:
I was wondering what the advantage is for using this board vs the standard 10Mhz external reference on the 9700?
73 Eric WD8KNL _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views
of
AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite
program!
Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership.
Opinions expressed
are solely those of the author, and do not reflect the official views of
AMSAT-NA.
Not an AMSAT-NA member? Join now to support the amateur satellite
program!
Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Thank You Mark for the answer and the detailed notes. 73 Kevin
On 2/15/2020 21:42, Mark Jessop wrote:
In short, yes.
I have performed phase noise measurements on my IC-9700, with and without injection locking. I am currently using a Leo Bodnar Mini GPSDO as the reference, though using a MiniKits injection board (Leo wasn't selling his at the time). I had to do this kind of locking as there was noticeable drift when attempting 70cm EME contacts with the IC-9700 unlocked, which was causing degradation in decode performance. With the radio locked there are no issues.
The test equipment was a Symmetricom 5125A Phase Noise Test Set, and I was using a 160 MHz Wenzel as a reference. The 5125A only works on input signals up to 400 MHz, so for 70cm and 23cm I mixed the signal down to ~30 MHz using a Minicircuits LAVI-2VH, with the LO generated by a R&S SMA100B. The rig was powered from 2x 100Ah batteries, and the GPSDOs were powered from a 5V linear bench supply.
I tested:
- (2m/70cm/23cm) Unlocked IC-9700, transmitting for ~5 minutes to let
the drift settle as best as it can.
- (2m/70cm) IC-9700 + MiniKits Coupler board, driven with the MiniKits
GPS-9700 (+10 dBm)
- (2m/70cm/23cm) IC-9700 + MiniKits Coupler board, driven with a Leo
Bodnar Mini GPSDO (maximum drive, which is ~+10 dBm I believe)
- (2m only) IC-9700 + MiniKits Coupler board, driven with the R&S
SMA100B (+10 dBm)
Plots of the results are here: https://imgur.com/a/iFi527l
I guess the key point is that there is no degradation of transmit phase noise observed when using any of the injection locking solutions. While I did previously see some wide-band phase noise differences between the MiniKits and Leo Bodnar LO's (as measured at 49.152 MHz), this doesn't translate to a degradation at the output of the transmitter. I'm not seeing the wide-band noise improvements when injection locked that others have seen.
There appears to be a slight improvement in close-in phase noise when injection locked with the GPS-9700 and Mini-GPSDO (and a big improvement when using the SMA100B, but that sig-gen costs 20x more than the rig does), but I wouldn't read too much into the close-in results as I only had time to run each measurement for ~5 minutes or so. However, note that the test-set noise floor (shaded area) is *well* below the measured results.
73 Mark VK5QI
On Sun, Feb 16, 2020 at 9:28 AM Kevin via AMSAT-BB <[email protected] mailto:[email protected]> wrote:
I wonder if anyone who has all the needed equipment to test has verified that the output of the 9700 is still clean after this mod? In the past ext reflock boards compared the radios osc to a gps locked 10mhz signal and adjusted the trim voltage going to the vctcxo so levels were not touched, the radio was as clean or dirty as it was when it left the factory. Now with this mod (if I understand it correctly) the main osc is still running and they are just pumping a much stronger signal into the master osc area until it drowns out the original osc and the radio locks to it. So the question comes up are they then overdriving the osc chain downline and distorting? and is the original osc signal still there in the background now as noise? Might be a interesting project to find out. 73 Kevin wa7fwf On 2/15/2020 14:08, Bob Hammond via AMSAT-BB wrote: > This is a good explanation: > > "With the current firmware, users have observed frequency drift when using > narrow bandwidth modes. Using an external 10 MHz and the firmware reduces > the size of the frequency drifts by updating the corrections to the master > oscillator more frequently. The drift is still there,,,,, With the 49.152 > MHz injector board and a good external 49.152 MHz GPS-locked oscillator, > the external oscillator locks the internal oscillator and the drift issue > is eliminated. The drift is probably not important on FM and most may not > notice the issue on SSB. But it is important to eliminate the drift if you > are using JT65 and similar narrow bandwidth modes." > > Copied from the Facebook ic-9700 group and a post by Peter Freeman in reply > to Tim Goodrich's question: > https://www.facebook.com/groups/163460540873662/ > > Bob W7OTJ > > On Sat, Feb 15, 2020 at 1:53 PM Bob Hammond <[email protected] <mailto:[email protected]>> wrote: > >> Eric, >> >> I found much information on the design and benefits of a GPSDO and >> reference board for the IC-9700 here: >> >> https://www.minikits.com.au/gps9700#wspr >> >> The Mini-Kits version is only slightly different than the Leo Bodnar >> version however the designs are virtually identical. >> >> >> http://www.leobodnar.com/shop/index.php?main_page=product_info&products_id=301 >> >> http://www.leobodnar.com/shop/index.php?main_page=product_info&products_id=352 >> >> Bob W7OTJ >> >> On Sat, Feb 15, 2020 at 8:16 AM kd8drg.admin--- via AMSAT-BB < >> [email protected] <mailto:[email protected]>> wrote: >> >>> I was wondering what the advantage is for using this board vs the >>> standard 10Mhz external reference on the 9700? >>> >>> 73 >>> Eric >>> WD8KNL >>> _______________________________________________ >>> Sent via [email protected] <mailto:[email protected]>. AMSAT-NA makes this open forum available >>> to all interested persons worldwide without requiring membership. >>> Opinions expressed >>> are solely those of the author, and do not reflect the official views of >>> AMSAT-NA. >>> Not an AMSAT-NA member? Join now to support the amateur satellite program! >>> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb >>> > _______________________________________________ > Sent via [email protected] <mailto:[email protected]>. AMSAT-NA makes this open forum available > to all interested persons worldwide without requiring membership. Opinions expressed > are solely those of the author, and do not reflect the official views of AMSAT-NA. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via [email protected] <mailto:[email protected]>. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
participants (5)
-
Bob Hammond -
kd8drg.admin＠nert-arc.org -
Kevin -
Mark Jessop -
Mark L. Hammond