Where does this common spurious transmission come from? Is there a quality difference? The Next CEO of Stack OverflowIs there a name for the demodulation technique described here using the parallax propeller?How to calculate if low-pass filtering is sufficient?Is there an advantage with having a DC bias for a FM radio transmission?Is there any way in which elevation *does* affect medium frequency (AM radio) transmissions?Is this the Correct Ferrite Core to Reduce RFI as a Common Mode Choke?
How did people program for Consoles with multiple CPUs?
Is it ever safe to open a suspicious HTML file (e.g. email attachment)?
Why do remote US companies require working in the US?
Why is the US ranked as #45 in Press Freedom ratings, despite its extremely permissive free speech laws?
Which one is the true statement?
Axiom Schema vs Axiom
Calculator final project in Python
Writing differences on a blackboard
Is it possible to replace duplicates of a character with one character using tr
Why did CATV standarize in 75 ohms and everyone else in 50?
What connection does MS Office have to Netscape Navigator?
Is it professional to write unrelated content in an almost-empty email?
What steps are necessary to read a Modern SSD in Medieval Europe?
Is French Guiana a (hard) EU border?
How many extra stops do monopods offer for tele photographs?
What did we know about the Kessel run before the prequels?
How to get from Geneva Airport to Metabief, Doubs, France by public transport?
How to check if all elements of 1 list are in the *same quantity* and in any order, in the list2?
Would a completely good Muggle be able to use a wand?
Is it convenient to ask the journal's editor for two additional days to complete a review?
Why isn't the Mueller report being released completely and unredacted?
How is this set of matrices closed under multiplication?
Is wanting to ask what to write an indication that you need to change your story?
Can I use the load factor to estimate the lift?
Where does this common spurious transmission come from? Is there a quality difference?
The Next CEO of Stack OverflowIs there a name for the demodulation technique described here using the parallax propeller?How to calculate if low-pass filtering is sufficient?Is there an advantage with having a DC bias for a FM radio transmission?Is there any way in which elevation *does* affect medium frequency (AM radio) transmissions?Is this the Correct Ferrite Core to Reduce RFI as a Common Mode Choke?
$begingroup$
I decided to see what my ham transmissions look like on an SDR and was kind of shocked to see how much leaks out. The waterfall display is split between two handhelds during transmit. There are a couple large energy spikes at +/- 800kHz to the 431.5MHz transmitting frequency.
Given that both radios spurious emissions are lined up and similar I'm guessing it is common and due to some sort of harmonic effect, possibly from implementing similar architecture.
Is there any negative to the less dispersed transmission of the bottom device/waterfall? The top half of the waterfall display is from a handheld transceiver that is much higher in quality than the one captured on the bottom half. Interestingly the SDR picks up the better handhelds audio much better even though voice communication between handheld devices is fine.
software-defined-radio rfi transceiver transmitter
asked 4 hours ago
RobCRobC
82
New contributor
RobC is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
add a comment |
$begingroup$
I decided to see what my ham transmissions look like on an SDR and was kind of shocked to see how much leaks out. The waterfall display is split between two handhelds during transmit. There are a couple large energy spikes at +/- 800kHz to the 431.5MHz transmitting frequency.
Given that both radios spurious emissions are lined up and similar I'm guessing it is common and due to some sort of harmonic effect, possibly from implementing similar architecture.
Is there any negative to the less dispersed transmission of the bottom device/waterfall? The top half of the waterfall display is from a handheld transceiver that is much higher in quality than the one captured on the bottom half. Interestingly the SDR picks up the better handhelds audio much better even though voice communication between handheld devices is fine.
software-defined-radio rfi transceiver transmitter
asked 4 hours ago
RobCRobC
82
New contributor
RobC is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
1
$begingroup$
Welcome to SE! Is there any chance the difference is related to overload of the SDR? For example, is there any indication that the ADC is being saturated? Also, are the radios putting out the same power, into similar antennas and coupling equally to the SDR?
$endgroup$
– Brian K1LI
4 hours ago
$begingroup$
@BrianK1LI I was just using the 'low' settings on the handhelds about 3ft from the antenna. I just tried both about 30ft away and got the exact same waveforms.
$endgroup$
– RobC
4 hours ago
add a comment |
$begingroup$
I decided to see what my ham transmissions look like on an SDR and was kind of shocked to see how much leaks out. The waterfall display is split between two handhelds during transmit. There are a couple large energy spikes at +/- 800kHz to the 431.5MHz transmitting frequency.
Given that both radios spurious emissions are lined up and similar I'm guessing it is common and due to some sort of harmonic effect, possibly from implementing similar architecture.
Is there any negative to the less dispersed transmission of the bottom device/waterfall? The top half of the waterfall display is from a handheld transceiver that is much higher in quality than the one captured on the bottom half. Interestingly the SDR picks up the better handhelds audio much better even though voice communication between handheld devices is fine.
software-defined-radio rfi transceiver transmitter
asked 4 hours ago
RobCRobC
82
New contributor
RobC is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
I decided to see what my ham transmissions look like on an SDR and was kind of shocked to see how much leaks out. The waterfall display is split between two handhelds during transmit. There are a couple large energy spikes at +/- 800kHz to the 431.5MHz transmitting frequency.
Given that both radios spurious emissions are lined up and similar I'm guessing it is common and due to some sort of harmonic effect, possibly from implementing similar architecture.
Is there any negative to the less dispersed transmission of the bottom device/waterfall? The top half of the waterfall display is from a handheld transceiver that is much higher in quality than the one captured on the bottom half. Interestingly the SDR picks up the better handhelds audio much better even though voice communication between handheld devices is fine.
software-defined-radio rfi transceiver transmitter
software-defined-radio rfi transceiver transmitter
asked 4 hours ago
RobCRobC
82
New contributor
RobC is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 4 hours ago
RobCRobC
82
New contributor
RobC is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 4 hours ago
RobCRobC
82
New contributor
RobC is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 4 hours ago
RobCRobC
82
asked 4 hours ago
RobCRobC
82
82
New contributor
RobC is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
RobC is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
RobC is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
1
$begingroup$
Welcome to SE! Is there any chance the difference is related to overload of the SDR? For example, is there any indication that the ADC is being saturated? Also, are the radios putting out the same power, into similar antennas and coupling equally to the SDR?
$endgroup$
– Brian K1LI
4 hours ago
$begingroup$
@BrianK1LI I was just using the 'low' settings on the handhelds about 3ft from the antenna. I just tried both about 30ft away and got the exact same waveforms.
$endgroup$
– RobC
4 hours ago
add a comment |
1
$begingroup$
Welcome to SE! Is there any chance the difference is related to overload of the SDR? For example, is there any indication that the ADC is being saturated? Also, are the radios putting out the same power, into similar antennas and coupling equally to the SDR?
$endgroup$
– Brian K1LI
4 hours ago
$begingroup$
@BrianK1LI I was just using the 'low' settings on the handhelds about 3ft from the antenna. I just tried both about 30ft away and got the exact same waveforms.
$endgroup$
– RobC
4 hours ago
1
1
$begingroup$
Welcome to SE! Is there any chance the difference is related to overload of the SDR? For example, is there any indication that the ADC is being saturated? Also, are the radios putting out the same power, into similar antennas and coupling equally to the SDR?
$endgroup$
– Brian K1LI
4 hours ago
$begingroup$
Welcome to SE! Is there any chance the difference is related to overload of the SDR? For example, is there any indication that the ADC is being saturated? Also, are the radios putting out the same power, into similar antennas and coupling equally to the SDR?
$endgroup$
– Brian K1LI
4 hours ago
$begingroup$
@BrianK1LI I was just using the 'low' settings on the handhelds about 3ft from the antenna. I just tried both about 30ft away and got the exact same waveforms.
$endgroup$
– RobC
4 hours ago
$begingroup$
@BrianK1LI I was just using the 'low' settings on the handhelds about 3ft from the antenna. I just tried both about 30ft away and got the exact same waveforms.
$endgroup$
– RobC
4 hours ago
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
This is very likely to be be due to overload of the receiver. A quick, rough way to tell the difference:
- Tune your SDR receiver so the waterfall center frequency is not the same as the transmitter's frequency.
- Transmit.
- Check whether the spurs you see are symmetric about the transmitter's frequency or the receiver's frequency. This tells you which side generated them.
Also, if transmitting causes the entire waterfall to rise up then you definitely have an overload problem.
How to eliminate overload: First, make sure your receiver's RF gain is set to the minimum level, and AGC (if any) is off. Then try these things:
- Replace the transmitter's antenna with a dummy load.
- Replace the receiver's antenna with a dummy load or terminator, or if neither is available, just leave the antenna port unconnected.
- Get more distance.
answered 3 hours ago
Kevin Reid AG6YO♦Kevin Reid AG6YO
16.4k33170
$endgroup$
add a comment |
Your Answer
StackExchange.ifUsing("editor", function ()
return StackExchange.using("mathjaxEditing", function ()
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix)
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
);
);
, "mathjax-editing");
StackExchange.ifUsing("editor", function ()
return StackExchange.using("schematics", function ()
StackExchange.schematics.init();
);
, "cicuitlab");
StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "520"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);
else
createEditor();
);
function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);
);
RobC is a new contributor. Be nice, and check out our Code of Conduct.
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fham.stackexchange.com%2fquestions%2f13163%2fwhere-does-this-common-spurious-transmission-come-from-is-there-a-quality-diffe%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
This is very likely to be be due to overload of the receiver. A quick, rough way to tell the difference:
- Tune your SDR receiver so the waterfall center frequency is not the same as the transmitter's frequency.
- Transmit.
- Check whether the spurs you see are symmetric about the transmitter's frequency or the receiver's frequency. This tells you which side generated them.
Also, if transmitting causes the entire waterfall to rise up then you definitely have an overload problem.
How to eliminate overload: First, make sure your receiver's RF gain is set to the minimum level, and AGC (if any) is off. Then try these things:
- Replace the transmitter's antenna with a dummy load.
- Replace the receiver's antenna with a dummy load or terminator, or if neither is available, just leave the antenna port unconnected.
- Get more distance.
answered 3 hours ago
Kevin Reid AG6YO♦Kevin Reid AG6YO
16.4k33170
$endgroup$
add a comment |
$begingroup$
This is very likely to be be due to overload of the receiver. A quick, rough way to tell the difference:
- Tune your SDR receiver so the waterfall center frequency is not the same as the transmitter's frequency.
- Transmit.
- Check whether the spurs you see are symmetric about the transmitter's frequency or the receiver's frequency. This tells you which side generated them.
Also, if transmitting causes the entire waterfall to rise up then you definitely have an overload problem.
How to eliminate overload: First, make sure your receiver's RF gain is set to the minimum level, and AGC (if any) is off. Then try these things:
- Replace the transmitter's antenna with a dummy load.
- Replace the receiver's antenna with a dummy load or terminator, or if neither is available, just leave the antenna port unconnected.
- Get more distance.
answered 3 hours ago
Kevin Reid AG6YO♦Kevin Reid AG6YO
16.4k33170
$endgroup$
add a comment |
$begingroup$
This is very likely to be be due to overload of the receiver. A quick, rough way to tell the difference:
- Tune your SDR receiver so the waterfall center frequency is not the same as the transmitter's frequency.
- Transmit.
- Check whether the spurs you see are symmetric about the transmitter's frequency or the receiver's frequency. This tells you which side generated them.
Also, if transmitting causes the entire waterfall to rise up then you definitely have an overload problem.
How to eliminate overload: First, make sure your receiver's RF gain is set to the minimum level, and AGC (if any) is off. Then try these things:
- Replace the transmitter's antenna with a dummy load.
- Replace the receiver's antenna with a dummy load or terminator, or if neither is available, just leave the antenna port unconnected.
- Get more distance.
answered 3 hours ago
Kevin Reid AG6YO♦Kevin Reid AG6YO
16.4k33170
$endgroup$
This is very likely to be be due to overload of the receiver. A quick, rough way to tell the difference:
- Tune your SDR receiver so the waterfall center frequency is not the same as the transmitter's frequency.
- Transmit.
- Check whether the spurs you see are symmetric about the transmitter's frequency or the receiver's frequency. This tells you which side generated them.
Also, if transmitting causes the entire waterfall to rise up then you definitely have an overload problem.
How to eliminate overload: First, make sure your receiver's RF gain is set to the minimum level, and AGC (if any) is off. Then try these things:
- Replace the transmitter's antenna with a dummy load.
- Replace the receiver's antenna with a dummy load or terminator, or if neither is available, just leave the antenna port unconnected.
- Get more distance.
answered 3 hours ago
Kevin Reid AG6YO♦Kevin Reid AG6YO
16.4k33170
answered 3 hours ago
Kevin Reid AG6YO♦Kevin Reid AG6YO
16.4k33170
answered 3 hours ago
Kevin Reid AG6YO♦Kevin Reid AG6YO
16.4k33170
answered 3 hours ago
Kevin Reid AG6YO♦Kevin Reid AG6YO
16.4k33170
16.4k33170
add a comment |
add a comment |
RobC is a new contributor. Be nice, and check out our Code of Conduct.
RobC is a new contributor. Be nice, and check out our Code of Conduct.
RobC is a new contributor. Be nice, and check out our Code of Conduct.
RobC is a new contributor. Be nice, and check out our Code of Conduct.
Thanks for contributing an answer to Amateur Radio Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fham.stackexchange.com%2fquestions%2f13163%2fwhere-does-this-common-spurious-transmission-come-from-is-there-a-quality-diffe%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
1
$begingroup$
Welcome to SE! Is there any chance the difference is related to overload of the SDR? For example, is there any indication that the ADC is being saturated? Also, are the radios putting out the same power, into similar antennas and coupling equally to the SDR?
$endgroup$
– Brian K1LI
4 hours ago
$begingroup$
@BrianK1LI I was just using the 'low' settings on the handhelds about 3ft from the antenna. I just tried both about 30ft away and got the exact same waveforms.
$endgroup$
– RobC
4 hours ago