Re: Using NanoVNA to measure receive antenna port impedance
#measurement
Unless you live in an extremely RFI prone and RFI polluted area, you won't
hear "antenna noise" on a crystal set.
Further, the crystal set runs on voltage so the high-Z antenna is quite
appropriate, but not for the 50-ohm system of the NANOs.
The one I finally built a decade or so ago for fun, used taps on the
primary coil of the LC tuned network for the detector. That enables
adjustment of the trade-off between recovered audio and selectivity (tuned
Q). I coupled the antenna to the main coil of the LC network through a
much smaller (inductance) coil to allow best selectivity of the main
inductor. Here in N. Colorado in the evening when the D-Layer dissolves,
I've detected as many and separated up to 23 stations using a 480-foot long
doublet. That's in the presence of our nemesis blowtorch at 760 kHz out of
Boulder which at times measures as much as -30 dBm into 50-ohms (spectrum
analuzer).
To better understand resonance, I believe everyone starting in ham radio
should build his/her own crystal radio. It's an excellent
teaching/learning tool!
Dave - W?LEV
toggle quoted message
Show quoted text
On Thu, Feb 10, 2022 at 7:01 PM Arie Kleingeld PA3A <pa3a@...> wrote: Hi Andy,
I understand that you are talking about a crystal radio being an
LC-circuit, a diode plus capacitor and a headset?
You could measure the imput impedance of that receiver. Thing is that a
strong signal of a VNA could drive the diode that it would take current.
Then the VNA probably will see another impedance that when the diode was
not conducting.
That is what the article was about and why I made that simple
attenuators to prevent that. And also wanted to test how well my
nanoVNA would cope with that.
Those simple crystal receivers usually are used in MF-range, well I did
once in a while. The antenna ( most times a piece of wire) will have a
pretty high impedance (resistance and also capacitive reactance) if you
measure it. The input impedance of the receiver will be far off 50 ohms
so thinking about 50 ohms -matching procedures is not the way to go.
Tapping the antennawire into the coil (directly of via a coupled loop)
and tuning the C of the LC circuit is the way I would choose and see
what happens. If you hear a lot of bandnoise when you connect the
antenna and you can hear the stations you expect, you are on the right
path.
That article by the way was one in a series of seven. English versions
were all published in the Communicator.
73,
Arie PA3A
Op 10-2-2022 om 15:14 schreef Andrew Kurtz via groups.io:
Hi Arie, read your article with great interest. I understand my nanoVNA, I think, and I understand complex algebra and Z = R + jX. But I
get VERY confused by standard radio or ham talk. I made a crystal radio
over the past 2 years, and never understood why or how it would be 50
ohms. I always wanted to measure my Z, but I think the main thing the
antenna signal is ¡°looking at¡± is my diode, since my tank circuit has
near-infinite resistance and thus is almost an open circuit. Are you
suggesting I can simply plug my nanoVNA in where my antenna usually goes
and get a receiver input impedance? Also, you spent a bunch of time on an
attenuator, but later (I think) you concluded you didn¡¯t need it. Why would
I want one? Any other suggestions for a naive beginner? I am thinking
about matching Z from antenna to receiver, but I can¡¯t measure either, and
when I guess at values and then design a little LC circuit to match
impedances, I find it will resonate at darn near my target f, sending my
desired signal to ground!
Andy
On Feb 10, 2022, at 5:43 AM, Arie Kleingeld PA3A<pa3a@...>
wrote:
Coming back on the title, how to measure...
I wrote an article about that a couple of months ago, measuring the
input impedance of a Elecraft K3 receiver.
It was published in the SARC Communicator sept- Oct 2021. This is the
link:
See page 43
73,
Arie PA3A
--
*Dave - W?LEV*
*Just Let Darwin Work*
|
Re: Using NanoVNA to measure receive antenna port impedance
#measurement
Hi Andy,
I understand that you are talking about a crystal radio being an LC-circuit, a diode plus capacitor and a headset?
You could measure the imput impedance of that receiver. Thing is that a strong signal of a VNA could drive the diode that it would take current. Then the VNA probably will see another impedance that when the diode was not conducting.
That is what the article was about and why I made that simple attenuators to prevent that. And also wanted to test how well? my nanoVNA would cope with that.
Those simple crystal receivers usually are used in MF-range, well I did once in a while. The antenna ( most times a piece of wire) will have a pretty high impedance (resistance and also capacitive reactance) if you measure it. The input impedance of the receiver will be far off 50 ohms so thinking about 50 ohms -matching procedures is not the way to go.
Tapping the antennawire into the coil (directly of via a coupled loop) and tuning the C of the LC circuit is the way I would choose and see what happens. If you hear a lot of bandnoise when you connect the antenna and you can hear the stations you expect, you are on the right path.
That article by the way was one in a series of seven. English versions were all published in the Communicator.
73,
Arie PA3A
Op 10-2-2022 om 15:14 schreef Andrew Kurtz via groups.io:
toggle quoted message
Show quoted text
Hi Arie, read your article with great interest. I understand my nanoVNA, I think, and I understand complex algebra and Z = R + jX. But I get VERY confused by standard radio or ham talk. I made a crystal radio over the past 2 years, and never understood why or how it would be 50 ohms. I always wanted to measure my Z, but I think the main thing the antenna signal is ¡°looking at¡± is my diode, since my tank circuit has near-infinite resistance and thus is almost an open circuit. Are you suggesting I can simply plug my nanoVNA in where my antenna usually goes and get a receiver input impedance? Also, you spent a bunch of time on an attenuator, but later (I think) you concluded you didn¡¯t need it. Why would I want one? Any other suggestions for a naive beginner? I am thinking about matching Z from antenna to receiver, but I can¡¯t measure either, and when I guess at values and then design a little LC circuit to match impedances, I find it will resonate at darn near my target f, sending my desired signal to ground!
Andy
On Feb 10, 2022, at 5:43 AM, Arie Kleingeld PA3A<pa3a@...> wrote:
Coming back on the title, how to measure...
I wrote an article about that a couple of months ago, measuring the input impedance of a Elecraft K3 receiver.
It was published in the SARC Communicator sept- Oct 2021. This is the link:
See page 43
73,
Arie PA3A
|
Re: Using NanoVNA to measure receive antenna port impedance
#measurement
Hi Dave
And that port is designed to look at a 50 Ohm load, not look like a 50 Ohm load!
Sweeping the front end of most radios just gives you an idea of their preseclection.? ? ?Kent WA5VJB
toggle quoted message
Show quoted text
On Thursday, February 10, 2022, 10:51:56 AM CST, W0LEV <davearea51a@...> wrote: They don't try.? It's that simple.? I've measured only one "vintage" radio of some 30 that put S-9 close to -73 dBm.? That was the Swan 100MX.? Of course, the rest of the S-Meter response is wonkered as is the Kenwood TS-2000. The ability to indicate proper S-Units vs. input power has been around since cell phones.? There is an 80 dB dynamic range requirement to properly measure the received strength for cell phones to properly operate.? It's the RSS output from the "IF" chip, or equivalent.? This could have easily been incorporated into our radios long....long ago, but they didn't. Today, with the SDR receivers, it's a no-brainer and they are pretty accurate (at least for my Icom 7300, 7610, Airspys, and RSP). Dave - W?LEV On Thu, Feb 10, 2022 at 2:06 AM Max via groups.io <kg4pid= [email protected]> wrote: ? I believe it. My very old (now) Icom 2100 single band VHF radio is even
worse. I've seen the meter go from S1 to S9 with only a 6 to 7 db increase
in power from the other end! Just asking, is it really that hard to measure
signal strength with even the least bit of accuracy in a radio? Or it they
just didn't try?
Max KG4PID
? On Wednesday, February 9, 2022, 07:36:03 PM CST, W0LEV <
davearea51a@...> wrote:
? Input regarding Kenwood S-Meters.? I have and have rigorously measured the
S-Meter input power vs. S-meter indication.? It's off the wall for that
radio, if there were a wall!!? At some points below S-9, as little as 1 dBm
difference produces an additional S-Unit increase/decrease.? S-9 is no
where near -73 dBm.? However, above S-9, it's not bad for every 10 dB
increase in input power.? If it's not a modern SDR, the S-Meter doesn't
mean squat - even the Collins S-Line!!!!!!
With S-9 at -73 dBm, that would be +34 dBuV in a non-reactive 50-ohm
system.? 20 over S-9 would be 40 dB (voltage) over that or +74 dBuV.? To be
rigorous, the given value of 100 eBuV is incorrect to be rigorous.? What's
more, what does Kenwood mean by "dBuVEMF"???? What the dickens does the
added "EMF" refer to????
Dave - W?LEV
On Wed, Feb 9, 2022 at 5:25 AM VK2CZ DAVID <16240244c1@...> wrote:
During Kenwood transceiver bench alignments, they specify 100dBuVEMF as
the S9+20 outer marker.? This equates to -1dBm.? As an anecdote, during a
contest with multi-transmitters, we saw around 3Volts of RF at one receiver
(tuned to a different band of course), and it survived quite happily. Best
I can make out, the NanoVNA only outputs like -10dBm.. ??
--
*Dave - W?LEV*
*Just Let Darwin Work*
-- *Dave - W?LEV* *Just Let Darwin Work*
|
Re: Using NanoVNA to measure receive antenna port impedance
#measurement
They don't try. It's that simple. I've measured only one "vintage" radio of some 30 that put S-9 close to -73 dBm. That was the Swan 100MX. Of course, the rest of the S-Meter response is wonkered as is the Kenwood TS-2000. The ability to indicate proper S-Units vs. input power has been around since cell phones. There is an 80 dB dynamic range requirement to properly measure the received strength for cell phones to properly operate. It's the RSS output from the "IF" chip, or equivalent. This could have easily been incorporated into our radios long....long ago, but they didn't. Today, with the SDR receivers, it's a no-brainer and they are pretty accurate (at least for my Icom 7300, 7610, Airspys, and RSP). Dave - W?LEV On Thu, Feb 10, 2022 at 2:06 AM Max via groups.io <kg4pid= [email protected]> wrote: I believe it. My very old (now) Icom 2100 single band VHF radio is even
worse. I've seen the meter go from S1 to S9 with only a 6 to 7 db increase
in power from the other end! Just asking, is it really that hard to measure
signal strength with even the least bit of accuracy in a radio? Or it they
just didn't try?
Max KG4PID
On Wednesday, February 9, 2022, 07:36:03 PM CST, W0LEV <
davearea51a@...> wrote:
Input regarding Kenwood S-Meters. I have and have rigorously measured the
S-Meter input power vs. S-meter indication. It's off the wall for that
radio, if there were a wall!! At some points below S-9, as little as 1 dBm
difference produces an additional S-Unit increase/decrease. S-9 is no
where near -73 dBm. However, above S-9, it's not bad for every 10 dB
increase in input power. If it's not a modern SDR, the S-Meter doesn't
mean squat - even the Collins S-Line!!!!!!
With S-9 at -73 dBm, that would be +34 dBuV in a non-reactive 50-ohm
system. 20 over S-9 would be 40 dB (voltage) over that or +74 dBuV. To be
rigorous, the given value of 100 eBuV is incorrect to be rigorous. What's
more, what does Kenwood mean by "dBuVEMF"??? What the dickens does the
added "EMF" refer to????
Dave - W?LEV
On Wed, Feb 9, 2022 at 5:25 AM VK2CZ DAVID <16240244c1@...> wrote:
During Kenwood transceiver bench alignments, they specify 100dBuVEMF as
the S9+20 outer marker. This equates to -1dBm. As an anecdote, during a
contest with multi-transmitters, we saw around 3Volts of RF at one receiver
(tuned to a different band of course), and it survived quite happily. Best
I can make out, the NanoVNA only outputs like -10dBm.. ??
--
*Dave - W?LEV*
*Just Let Darwin Work*
-- *Dave - W?LEV* *Just Let Darwin Work*
|
Thank You
?Larry.
Joe
toggle quoted message
Show quoted text
On 2/10/2022 10:03 AM, Larry Rothman wrote: Yes
On Thursday, February 10, 2022, 09:59:26 a.m. EST, Joe WB9SBD<nss@...> wrote:
Simple question
OK NanoVNA-H4 Unit is off and is charging via the USB cable.
Red light is flashing I assume meand charging
when it is steady and not flashing does that mean it is fully charged?
Joe
|
Yes
toggle quoted message
Show quoted text
On Thursday, February 10, 2022, 09:59:26 a.m. EST, Joe WB9SBD <nss@...> wrote:
Simple question
OK NanoVNA-H4 Unit is off and is charging via the USB cable.
Red light is flashing I assume meand charging
when it is steady and not flashing does that mean it is fully charged?
Joe
|
Simple question
OK NanoVNA-H4 Unit is off and is charging via the USB cable.
Red light is flashing I assume meand charging
when it is steady and not flashing does that mean it is fully charged?
Joe
|
Re: Using NanoVNA to measure receive antenna port impedance
#measurement
Hi Arie, read your article with great interest. I understand my nanoVNA, I think, and I understand complex algebra and Z = R + jX. But I get VERY confused by standard radio or ham talk. I made a crystal radio over the past 2 years, and never understood why or how it would be 50 ohms. I always wanted to measure my Z, but I think the main thing the antenna signal is ¡°looking at¡± is my diode, since my tank circuit has near-infinite resistance and thus is almost an open circuit. Are you suggesting I can simply plug my nanoVNA in where my antenna usually goes and get a receiver input impedance? Also, you spent a bunch of time on an attenuator, but later (I think) you concluded you didn¡¯t need it. Why would I want one? Any other suggestions for a naive beginner? I am thinking about matching Z from antenna to receiver, but I can¡¯t measure either, and when I guess at values and then design a little LC circuit to match impedances, I find it will resonate at darn near my target f, sending my desired signal to ground!
Andy
toggle quoted message
Show quoted text
On Feb 10, 2022, at 5:43 AM, Arie Kleingeld PA3A <pa3a@...> wrote:
Coming back on the title, how to measure...
I wrote an article about that a couple of months ago, measuring the input impedance of a Elecraft K3 receiver.
It was published in the SARC Communicator sept- Oct 2021. This is the link:
See page 43
73,
Arie PA3A
|
Re: Proper way to measure cable length
Hi dear friends!!!
What kind is your nanovna???
I has purchase few days ago a SAA 2 V2.2 but I cant find this option...
Can You help me please???
Em 07/02/2022 15:39, DiSlord escreveu:
toggle quoted message
Show quoted text
In my firmware exist option
Measure->Cable
User need select correct frequency range (minimum/maximim frequency depend from cable length on smitch chart must rotate by 180 degree)
As can see in this mode Nano measure impedance, length (need set correct velocity factor) and loss (at marker point, use s11 logmag / 2)
|
Re: Using NanoVNA to measure receive antenna port impedance
#measurement
Coming back on the title, how to measure...
I wrote an article about that a couple of months ago, measuring the input impedance of a Elecraft K3 receiver.
It was published in the SARC Communicator sept- Oct 2021. This is the link:
See page 43
73,
Arie PA3A
|
When I built my 486DX2 in 92, with huge help, my guru said to get 5x7 spiral-bound recipe card set to act as notes that he'd mention, as we go. It worked great!
I had the reference, and writing things down, acted like the only cheat sheet I ever made. Completed, I didn't need it. Writing it down after mentally condensing it forged the memory. Never repeated that, sadly, as it created my best grade ever.
New blood sees things with an unjaundiced eye. Making your own note-set, helps. It's a lil laborious, but almost a one-off.
BillSF9c
|
Re: Using NanoVNA to measure receive antenna port impedance
#measurement
Dave,
Slight gaffe on my part... the 100dBuVemf is to calibrate the 60dB over 9 S meter full scale on all Kenwood Transceivers..
The dBuVemf is the kirchoff voltage source for sig generators with 50 ohm output impedances connected to a 50ohm load. It's a painful unit to deal on all but the professional sig generators, ie snapshot of my E4438C Amplitude setting screen..
|
Re: Using NanoVNA to measure receive antenna port impedance
#measurement
Just lurking here, but does anyone actually look at an S meter while operating? Just kind of wondering. I'll admit I mostly do contests, so I'm way too busy to worry about the actual S meter reading. I would like it if they removed the S meter and put the front panel real estate to better use. Just me I guess. I used to work for HP/Agilent Microwave, and in that case we worried about 0.01dB in measurements. But on HF if someone actually asks how loud they are I just kinda take a WAG at it. If you are louder than the noise I can hear you, so no problem. I guess we all have our different interests! Oh and yes, I do own a Nano-VNA. Real early one, works great for antenna projects and filters. I did have three HP VNAs before our big fire here, but they went up in smoke with everything else. But the Nano is way easier to move around. Plenty good enough for HF stuff. Ken K6MR ________________________________ From: [email protected] < [email protected]> on behalf of Max via groups.io <kg4pid@...> Sent: Wednesday, February 9, 2022 6:05 PM To: [email protected] < [email protected]> Subject: Re: [nanovna-users] Using NanoVNA to measure receive antenna port impedance #measurement I believe it. My very old (now) Icom 2100 single band VHF radio is even worse. I've seen the meter go from S1 to S9 with only a 6 to 7 db increase in power from the other end! Just asking, is it really that hard to measure signal strength with even the least bit of accuracy in a radio? Or it they just didn't try? Max KG4PID On Wednesday, February 9, 2022, 07:36:03 PM CST, W0LEV <davearea51a@...> wrote: Input regarding Kenwood S-Meters. I have and have rigorously measured the S-Meter input power vs. S-meter indication. It's off the wall for that radio, if there were a wall!! At some points below S-9, as little as 1 dBm difference produces an additional S-Unit increase/decrease. S-9 is no where near -73 dBm. However, above S-9, it's not bad for every 10 dB increase in input power. If it's not a modern SDR, the S-Meter doesn't mean squat - even the Collins S-Line!!!!!! With S-9 at -73 dBm, that would be +34 dBuV in a non-reactive 50-ohm system. 20 over S-9 would be 40 dB (voltage) over that or +74 dBuV. To be rigorous, the given value of 100 eBuV is incorrect to be rigorous. What's more, what does Kenwood mean by "dBuVEMF"??? What the dickens does the added "EMF" refer to???? Dave - W?LEV On Wed, Feb 9, 2022 at 5:25 AM VK2CZ DAVID <16240244c1@...> wrote: During Kenwood transceiver bench alignments, they specify 100dBuVEMF as
the S9+20 outer marker. This equates to -1dBm. As an anecdote, during a
contest with multi-transmitters, we saw around 3Volts of RF at one receiver
(tuned to a different band of course), and it survived quite happily. Best
I can make out, the NanoVNA only outputs like -10dBm.. ??
-- *Dave - W?LEV* *Just Let Darwin Work*
|
Yea I kept looking at the data sheet thinking, those dimensions can't be right! As much as wanted to order some to protect my equipment, I quickly realized that it would take a pick-n-place machine to mount those tiny parts in most cases. That tiny part is only .62 mm long or?0.02440945 in inches. Four of them will fit between the pins of the older chips!?
My hat is off to anyone that can do it manually. Don't sneeze or you WILL loose that part!
Max KG4PID
toggle quoted message
Show quoted text
On Wednesday, February 9, 2022, 04:26:40 PM CST, DOUGLAS WYMAN via groups.io <dkwyman@...> wrote: As a reality check for those whose soldering skills might not have kept up to this task (mine for example): The Infineon two terminal part is about the size of Thomas Jefferson¡¯s eyeball on a 2020 nickel. On Feb 4, 2022, at 9:59 AM, N2MS <mstangelo@...> wrote:
I checked this Infineon diode on Mouser and it shows "Not recommended for new design:
<>
Has anyone used this Bourns part:
<>
It has low capacitance the the 0603 size with solderable ends may be easier to solder to the connector.
Mike N2MS
On 02/04/2022 8:38 AM Reinier Gerritsen <r.gerritsen@...> wrote:
Solved this problem a few years ago. I protected my nanovna V2.2 with a
TVS diode: ESD101B102ELE6327XTMA1, a 5.5V TVS bi-directional diode from
Infineon, 0.1 pF capacitance.
Soldered directly at the input on the pcb. I did not see any difference
in return loss matching. You could introduce a series capacitor to
prevent DC connection related failures. I think (not for sure) that the
TX port does not have one, but the RX port does.
Had to replaced the input switches in 3 different nanovnaV2.2? units
failing in a timespan a few days. All units back to life now.
Reinier
|
Re: Using NanoVNA to measure receive antenna port impedance
#measurement
I believe it. My very old (now) Icom 2100 single band VHF radio is even worse. I've seen the meter go from S1 to S9 with only a 6 to 7 db increase in power from the other end! Just asking, is it really that hard to measure signal strength with even the least bit of accuracy in a radio? Or it they just didn't try?
Max KG4PID
toggle quoted message
Show quoted text
On Wednesday, February 9, 2022, 07:36:03 PM CST, W0LEV <davearea51a@...> wrote: Input regarding Kenwood S-Meters.? I have and have rigorously measured the S-Meter input power vs. S-meter indication.? It's off the wall for that radio, if there were a wall!!? At some points below S-9, as little as 1 dBm difference produces an additional S-Unit increase/decrease.? S-9 is no where near -73 dBm.? However, above S-9, it's not bad for every 10 dB increase in input power.? If it's not a modern SDR, the S-Meter doesn't mean squat - even the Collins S-Line!!!!!! With S-9 at -73 dBm, that would be +34 dBuV in a non-reactive 50-ohm system.? 20 over S-9 would be 40 dB (voltage) over that or +74 dBuV.? To be rigorous, the given value of 100 eBuV is incorrect to be rigorous.? What's more, what does Kenwood mean by "dBuVEMF"???? What the dickens does the added "EMF" refer to???? Dave - W?LEV On Wed, Feb 9, 2022 at 5:25 AM VK2CZ DAVID <16240244c1@...> wrote: During Kenwood transceiver bench alignments, they specify 100dBuVEMF as
the S9+20 outer marker.? This equates to -1dBm.? As an anecdote, during a
contest with multi-transmitters, we saw around 3Volts of RF at one receiver
(tuned to a different band of course), and it survived quite happily.? Best
I can make out, the NanoVNA only outputs like -10dBm.. ??
-- *Dave - W?LEV* *Just Let Darwin Work*
|
Re: Using NanoVNA to measure receive antenna port impedance
#measurement
Input regarding Kenwood S-Meters. I have and have rigorously measured the
S-Meter input power vs. S-meter indication. It's off the wall for that
radio, if there were a wall!! At some points below S-9, as little as 1 dBm
difference produces an additional S-Unit increase/decrease. S-9 is no
where near -73 dBm. However, above S-9, it's not bad for every 10 dB
increase in input power. If it's not a modern SDR, the S-Meter doesn't
mean squat - even the Collins S-Line!!!!!!
With S-9 at -73 dBm, that would be +34 dBuV in a non-reactive 50-ohm
system. 20 over S-9 would be 40 dB (voltage) over that or +74 dBuV. To be
rigorous, the given value of 100 eBuV is incorrect to be rigorous. What's
more, what does Kenwood mean by "dBuVEMF"??? What the dickens does the
added "EMF" refer to????
Dave - W?LEV
toggle quoted message
Show quoted text
On Wed, Feb 9, 2022 at 5:25 AM VK2CZ DAVID <16240244c1@...> wrote: During Kenwood transceiver bench alignments, they specify 100dBuVEMF as
the S9+20 outer marker. This equates to -1dBm. As an anecdote, during a
contest with multi-transmitters, we saw around 3Volts of RF at one receiver
(tuned to a different band of course), and it survived quite happily. Best
I can make out, the NanoVNA only outputs like -10dBm.. ??
--
*Dave - W?LEV*
*Just Let Darwin Work*
|
As a reality check for those whose soldering skills might not have kept up to this task (mine for example):
The Infineon two terminal part is about the size of Thomas Jefferson¡¯s eyeball on a 2020 nickel.
toggle quoted message
Show quoted text
On Feb 4, 2022, at 9:59 AM, N2MS <mstangelo@...> wrote:
I checked this Infineon diode on Mouser and it shows "Not recommended for new design:
<>
Has anyone used this Bourns part:
<>
It has low capacitance the the 0603 size with solderable ends may be easier to solder to the connector.
Mike N2MS
On 02/04/2022 8:38 AM Reinier Gerritsen <r.gerritsen@...> wrote:
Solved this problem a few years ago. I protected my nanovna V2.2 with a
TVS diode: ESD101B102ELE6327XTMA1, a 5.5V TVS bi-directional diode from
Infineon, 0.1 pF capacitance.
Soldered directly at the input on the pcb. I did not see any difference
in return loss matching. You could introduce a series capacitor to
prevent DC connection related failures. I think (not for sure) that the
TX port does not have one, but the RX port does.
Had to replaced the input switches in 3 different nanovnaV2.2 units
failing in a timespan a few days. All units back to life now.
Reinier
|
Re: Proper way to measure cable length
OK guys, here's a quick shot I found on the web. don't remember where but hopefully it'll answer your questions.
Mike C.
toggle quoted message
Show quoted text
On 2/7/2022 1:10 PM, Joe wrote: For an example, it is extremely helpful when troubleshooting a transmission line fault. I have an Anritsu Sitemaster that I use to do DTF (Distance to Fault) tests. I can locate a problem, usually within a few feet, and save lots of time taking things apart that are not the problem.
I sometimes test a spool of hardline that we suspect has been shipped improperly on it's side and dropped. This can cause the cable to deform and cause an impedance bump in the line. It's hard for a supplier to deny that the cable is bad when it's still on the spool and never unreeled.
Joe
On 2/7/2022 12:45 PM, Toad Laurence via groups.io wrote:
Dear all,
Could someone answer this:-
???????? Why is there this obsession to electrically measure the physical length of an arbitrary length of coax?
|
The wiki page Home
has been updated
by Larry Rothman <nlroth@...>.
Reason: Added Menu Structure Map links
Compare Revisions
|
Re: Ver 1.1.01 Menu structure Map
Yep. Printed out a menu map and embellished it with some handwritten notes. For just about every device I have, I also create a "Notes" document, where I add things I find/figure out along the way, like the many things I learn in these and other forums. I do that for each significant piece of radio and lab equipment, my automobiles, etc...
|
Arie Kleingeld PA3A
DOUGLAS WYMAN
Mike C.
Lou W7HV