Leakage, tinySA
My tinySA arrived a few days ago. I'm happy.
It comes in a nice box with an antenna that extends to a foot, a USB charging
cable (mini, not micro) and a couple of cables.
It doesn't come with a manual. I haven't found a manual online. Their web
site is pretty good, but sometimes I like a document organized to be read by
turning pages rather than following links.
The minimum receive bandwidth is 3.1 kHz.
The specs say the lower frequency limit is 100 kHz but the UI doesn't enforce
that.
My strongest signal is at 30 MHz. It's -60 to -80 dBm as I wave it around.
At 100 kHz bandwidth, the noise floor is -110 dBm. The 30 MHz blip is clean
enough to see the shape of the receive bandwidth filter. (I'm assuming the
raw signal is much narrower than 3 kHz.)
I haven't figured out where it is coming from. At first, I thought it was
coming from low power do-it-yourself PCs.
https://www.mini-box.com/
If I get near them, lots of spurs near 30 MHz come up out of the noise. But
powering them off doesn't change the 30 MHz.
The 30 MHz is clean. I'm guessing it's the 3rd harmonic of 10 MHz. I only
have a few of them, but I don't like turning them off. Or maybe the 2nd
harmonic from the Lucent boxes. ??
The 10 MHz is stronger near coax carrying 10 MHz and next to a Z3801A. I'll
have to try some good cables. Anybody have a favorite source? Is there a
magic word? Do I have to specify the type of coax?
I have lots of Gigabit Ethernet. I have a blob at 125 MHz, and spurs at 120
MHz and 130 MHz. 120 has a little brother 18 kHz higher.
The normal power up mode scans 0 to 350 MHz with enough attenuation so that
most of my signals are lost in the noise. Sometimes it comes up without the
attenuation. Then I can see all sorts of stuff. The biggest ones are at 240
and 288 MHz.
I think there is a mode for overlaying displays. I haven't investigated.
Their web page has links to software to talk to it over the USB cable. I
haven't investigated. Plugging in the USB cable adds lots of cruft. The
software would be unusable unless you are looking at a strong signal or at
something in a hole that the cruft misses. It might work if you can freeze
the display, then plug in the USB cable to capture it.
--
These are my opinions. I hate spam.
Another data point: My newly-received TinySA has a big birdie at 10 MHz,
which is a
disappointment since I had hoped to use the unit as a sniffer to track down
leaks in my
10 MHz distribution system. This birdie in the TinySA persists even when
nothing is
connected to the input and does not vary in amplitude when I move around
the house,
or with time while I'm sitting still with the unit.
I, too, received no manual.
Dana
On Sat, Jan 16, 2021 at 5:28 AM Hal Murray hmurray@megapathdsl.net wrote:
My tinySA arrived a few days ago. I'm happy.
It comes in a nice box with an antenna that extends to a foot, a USB
charging
cable (mini, not micro) and a couple of cables.
It doesn't come with a manual. I haven't found a manual online. Their
web
site is pretty good, but sometimes I like a document organized to be read
by
turning pages rather than following links.
The minimum receive bandwidth is 3.1 kHz.
The specs say the lower frequency limit is 100 kHz but the UI doesn't
enforce
that.
My strongest signal is at 30 MHz. It's -60 to -80 dBm as I wave it
around.
At 100 kHz bandwidth, the noise floor is -110 dBm. The 30 MHz blip is
clean
enough to see the shape of the receive bandwidth filter. (I'm assuming
the
raw signal is much narrower than 3 kHz.)
I haven't figured out where it is coming from. At first, I thought it was
coming from low power do-it-yourself PCs.
https://www.mini-box.com/
If I get near them, lots of spurs near 30 MHz come up out of the noise.
But
powering them off doesn't change the 30 MHz.
The 30 MHz is clean. I'm guessing it's the 3rd harmonic of 10 MHz. I
only
have a few of them, but I don't like turning them off. Or maybe the 2nd
harmonic from the Lucent boxes. ??
The 10 MHz is stronger near coax carrying 10 MHz and next to a Z3801A.
I'll
have to try some good cables. Anybody have a favorite source? Is there a
magic word? Do I have to specify the type of coax?
I have lots of Gigabit Ethernet. I have a blob at 125 MHz, and spurs at
120
MHz and 130 MHz. 120 has a little brother 18 kHz higher.
The normal power up mode scans 0 to 350 MHz with enough attenuation so
that
most of my signals are lost in the noise. Sometimes it comes up without
the
attenuation. Then I can see all sorts of stuff. The biggest ones are at
240
and 288 MHz.
I think there is a mode for overlaying displays. I haven't investigated.
Their web page has links to software to talk to it over the USB cable. I
haven't investigated. Plugging in the USB cable adds lots of cruft. The
software would be unusable unless you are looking at a strong signal or at
something in a hole that the cruft misses. It might work if you can
freeze
the display, then plug in the USB cable to capture it.
--
These are my opinions. I hate spam.
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.
Hi
On Jan 16, 2021, at 5:32 AM, Hal Murray hmurray@megapathdsl.net wrote:
My tinySA arrived a few days ago. I'm happy.
It comes in a nice box with an antenna that extends to a foot, a USB charging
cable (mini, not micro) and a couple of cables.
It doesn't come with a manual. I haven't found a manual online. Their web
site is pretty good, but sometimes I like a document organized to be read by
turning pages rather than following links.
The minimum receive bandwidth is 3.1 kHz.
The specs say the lower frequency limit is 100 kHz but the UI doesn't enforce
that.
My strongest signal is at 30 MHz. It's -60 to -80 dBm as I wave it around.
At 100 kHz bandwidth, the noise floor is -110 dBm. The 30 MHz blip is clean
enough to see the shape of the receive bandwidth filter. (I'm assuming the
raw signal is much narrower than 3 kHz.)
I haven't figured out where it is coming from. At first, I thought it was
coming from low power do-it-yourself PCs.
https://www.mini-box.com/
If I get near them, lots of spurs near 30 MHz come up out of the noise. But
powering them off doesn't change the 30 MHz.
The 30 MHz is clean. I'm guessing it's the 3rd harmonic of 10 MHz. I only
have a few of them, but I don't like turning them off. Or maybe the 2nd
harmonic from the Lucent boxes. ??
The 10 MHz is stronger near coax carrying 10 MHz and next to a Z3801A.
First step is to pull the cable and put a 50 ohm load on the device ( 3801
in this case ). The radiation may not go down …. If it does go down, next
step is a clamp on ferrite on the coax. “Anything that will fit” is the first
choice there ….
I'll
have to try some good cables. Anybody have a favorite source? Is there a
magic word? Do I have to specify the type of coax?
If you don’t mind spending “many tens of dollars a foot” there are lots of choices
out there. They often come with strange mating connectors so the cable
is only the start of the cash outlay.
I would draw the line at LMR-400.
https://www.pasternack.com/50-ohm-low-loss-flexible-lmr400-pe-jacket-double-shielded-black-lmr-400-P.aspx https://www.pasternack.com/50-ohm-low-loss-flexible-lmr400-pe-jacket-double-shielded-black-lmr-400-P.aspx
Note that the term “flexible” is more in comparison to “rigid metal jacket” than
what you would normally expect on a test cable.
If you do want to go a bit more fancy than LMR400, stick with eBay and ten cents on
the dollar pricing… Connectors may be a bit worn, but the price is right.
https://www.ebay.com/itm/Megaphase-SF4-S1S5-96T-DC-to-4-GHz-50-96-SMA-to-SMA-R-Angle-RF-Test-Cable/231773017446?hash=item35f6bf9566:g:GU0AAOSwv-NWYJ3S https://www.ebay.com/itm/Megaphase-SF4-S1S5-96T-DC-to-4-GHz-50-96-SMA-to-SMA-R-Angle-RF-Test-Cable/231773017446?hash=item35f6bf9566:g:GU0AAOSwv-NWYJ3S
This is simply what is out there and seems to work pretty well. It is not the best of the
best by any means. It is something you can find on eBay.
If your application is one that rigid cable ( = solid metal jacket) will work, that
probably is a better bet. A thicker metal jacket is often a better jacket at 10 MHz.
I have lots of Gigabit Ethernet. I have a blob at 125 MHz, and spurs at 120
MHz and 130 MHz. 120 has a little brother 18 kHz higher.
Same trick with snap on ferrite cores applies here as well. If the core is big
enough, putting one or more turns through the core may help. Core size
vs cable size is what will limit you there …
Fun !!!
Bob
The normal power up mode scans 0 to 350 MHz with enough attenuation so that
most of my signals are lost in the noise. Sometimes it comes up without the
attenuation. Then I can see all sorts of stuff. The biggest ones are at 240
and 288 MHz.
I think there is a mode for overlaying displays. I haven't investigated.
Their web page has links to software to talk to it over the USB cable. I
haven't investigated. Plugging in the USB cable adds lots of cruft. The
software would be unusable unless you are looking at a strong signal or at
something in a hole that the cruft misses. It might work if you can freeze
the display, then plug in the USB cable to capture it.
--
These are my opinions. I hate spam.
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.
There is no birdies on mine that I can see, even as I decrease the RBW. -
Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
848-245-9115
-----Original Message-----
From: time-nuts time-nuts-bounces@lists.febo.com On Behalf Of Dana Whitlow
Sent: Saturday, January 16, 2021 6:45 AM
To: Discussion of precise time and frequency measurement
time-nuts@lists.febo.com
Subject: Re: [time-nuts] Leakage, tinySA
Another data point: My newly-received TinySA has a big birdie at 10 MHz,
which is a disappointment since I had hoped to use the unit as a sniffer to
track down leaks in my
10 MHz distribution system. This birdie in the TinySA persists even when
nothing is connected to the input and does not vary in amplitude when I move
around the house, or with time while I'm sitting still with the unit.
I, too, received no manual.
Dana
Sorry for the poor grammar on my post below.
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
848-245-9115
-----Original Message-----
From: time-nuts time-nuts-bounces@lists.febo.com On Behalf Of Mike Feher
Sent: Saturday, January 16, 2021 11:10 AM
To: 'Discussion of precise time and frequency measurement'
time-nuts@lists.febo.com
Subject: Re: [time-nuts] Leakage, tinySA
There is no birdies on mine that I can see, even as I decrease the RBW. -
Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
848-245-9115
-----Original Message-----
From: time-nuts time-nuts-bounces@lists.febo.com On Behalf Of Dana Whitlow
Sent: Saturday, January 16, 2021 6:45 AM
To: Discussion of precise time and frequency measurement
time-nuts@lists.febo.com
Subject: Re: [time-nuts] Leakage, tinySA
Another data point: My newly-received TinySA has a big birdie at 10 MHz,
which is a disappointment since I had hoped to use the unit as a sniffer to
track down leaks in my
10 MHz distribution system. This birdie in the TinySA persists even when
nothing is connected to the input and does not vary in amplitude when I move
around the house, or with time while I'm sitting still with the unit.
I, too, received no manual.
Dana
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On 1/16/21 04:32, Hal Murray wrote:
The 10 MHz is stronger near coax carrying 10 MHz and next to a Z3801A. I'll
have to try some good cables. Anybody have a favorite source? Is there a
magic word? Do I have to specify the type of coax?
Yes. RG400 or RG316. Do NOT use RG58 or RG174. Both RG400 and RG316 are
double-shielded to reduce leakage. The choice is dictated by length of
run and physical flexibility required. Mostly I use RG316 cables on the
bench. For more than a meter or so I go with RG400. You can get either
type of cable terminated with N, BNC, TNC, or SMA connectors.
All kinds of pre-made cable assemblies using RG316 are available from
Amazon for surprisingly-low prices. I can't buy the coax and connectors
for what I end up paying Amazon for completed cables. For RG400 I end up
making my own cable assemblies.
The LMR cables (Times Microwave and knock-offs) are pretty good too.
LMR195 is pretty good but not nearly as flexible as the aforementioned
cables. LMR400 is just too big and inflexible for easy use on the bench.
--
Brian Lloyd
706 Flightline
Spring Branch, TX 78070
brian@lloyd.aero mailto://brian@lloyd.aero
+1.210.802.8359
You can get custom-made decent quality cables with double shielded coax
(either RG-316D or RG-142) from China (where else?) for pretty low
prices. I am sure the cable isn't mil-spec but I cut a piece open and
the shield coverage, which is the main thing I worry about at HF
frequencies, is pretty good. The connector finish is sometimes a bit
rough (particularly the BNC bayonet part) but they hold up pretty well
and I haven't seen any damage from mating them.
The place I mainly work with is "RF Bat" or "SuperBat" at rfbat.com.
Ask for Amy and tell her I sent you. :-) (no commercial relationship, etc.)
John
On 1/16/21 12:40 PM, Brian Lloyd wrote:
On 1/16/21 04:32, Hal Murray wrote:
The 10 MHz is stronger near coax carrying 10 MHz and next to a
Z3801A. I'll
have to try some good cables. Anybody have a favorite source? Is
there a
magic word? Do I have to specify the type of coax?
Yes. RG400 or RG316. Do NOT use RG58 or RG174. Both RG400 and RG316 are
double-shielded to reduce leakage. The choice is dictated by length of
run and physical flexibility required. Mostly I use RG316 cables on the
bench. For more than a meter or so I go with RG400. You can get either
type of cable terminated with N, BNC, TNC, or SMA connectors.
All kinds of pre-made cable assemblies using RG316 are available from
Amazon for surprisingly-low prices. I can't buy the coax and connectors
for what I end up paying Amazon for completed cables. For RG400 I end up
making my own cable assemblies.
The LMR cables (Times Microwave and knock-offs) are pretty good too.
LMR195 is pretty good but not nearly as flexible as the aforementioned
cables. LMR400 is just too big and inflexible for easy use on the bench.
I use RG400 for most of my time nuts activities. When I switched from cheap RG58 style coax to RG400 a number of strange issues seemed to go away for me.
Your mileage may vary (:
Mark Spencer
mark@alignedsolutions.com
604 762 4099
On Jan 16, 2021, at 9:40 AM, Brian Lloyd brian@lloyd.aero wrote:
On 1/16/21 04:32, Hal Murray wrote:
The 10 MHz is stronger near coax carrying 10 MHz and next to a Z3801A. I'll
have to try some good cables. Anybody have a favorite source? Is there a
magic word? Do I have to specify the type of coax?
Yes. RG400 or RG316. Do NOT use RG58 or RG174. Both RG400 and RG316 are double-shielded to reduce leakage. The choice is dictated by length of run and physical flexibility required. Mostly I use RG316 cables on the bench. For more than a meter or so I go with RG400. You can get either type of cable terminated with N, BNC, TNC, or SMA connectors.
All kinds of pre-made cable assemblies using RG316 are available from Amazon for surprisingly-low prices. I can't buy the coax and connectors for what I end up paying Amazon for completed cables. For RG400 I end up making my own cable assemblies.
The LMR cables (Times Microwave and knock-offs) are pretty good too. LMR195 is pretty good but not nearly as flexible as the aforementioned cables. LMR400 is just too big and inflexible for easy use on the bench.
--
Brian Lloyd
706 Flightline
Spring Branch, TX 78070
brian@lloyd.aero mailto://brian@lloyd.aero
+1.210.802.8359
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