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Author Topic: Options for mounting a small 2 meter Yagi  (Read 537 times)

KK4GMU

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Re: Options for mounting a small 2 meter Yagi
« Reply #30 on: July 26, 2022, 11:41:41 AM »

Right. I forgot about the pilarization. As they say "No easy day."  Either half-baked polarization on my 30 degree pitched roof with moderate stealthiness, or good polarization without the stealth.
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K1KIM

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Re: Options for mounting a small 2 meter Yagi
« Reply #31 on: July 26, 2022, 12:05:51 PM »

Right. I forgot about the pilarization. As they say "No easy day."  Either half-baked polarization on my 30 degree pitched roof with moderate stealthiness, or good polarization without the stealth.

Laying the antenna on that 7/12 pitch roof is going to be poor vertically and horizontally for polarization.
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WB6BYU

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Re: Options for mounting a small 2 meter Yagi
« Reply #32 on: July 26, 2022, 03:36:36 PM »

Quote from: KK4GMU

The S meter reads 2 when the repeater is NOT transmitting.  It reads 3.5 when it IS transmitting.  The meter on my 7100 goes up to 60.

On the RSP/SDR (for some  reason I cannot post the screen shot now) there is a narrow (maybe 5 MHz wide) spike at 145.320 from the noise base of 137dBm to 130dBm.  I'm not sure how significant that is.



OK, that indicates that the signal is weak.  But you can see that whatever
background noise is reading 2 when the repeater is not transmitting may
be making it difficult to hear:  if that were zero instead, the repeater
signal would be further above the noise floor.

The bandwidth and filter settings in the radio might make a difference.

I would also test it with a temporary moveable antenna to see if the
signal strength changes significantly when you move around the yard
or on the roof.  With multipath, a foot or two can make a significant
difference.  I'm not convinced that is the issue, but it is a simple check
to make.


Yagis can be built in a wide range of sizes:  I've used 2-element yagis
on 2m that were less than 6" long for special purposes, and I have
several designs for 3-element yagis in the 16" to 20" range.  Yagis can
be built with thin wire elements that are very difficult to see from a
distance, especially if you can disguise the boom as some other
innocuous object on the roof.


But yagis aren't the only type of antenna to have gain, and, depending
on how much gain you need, there may be some other options.

For example, if you can mount two verticals on your roof (perhaps
disguised as vent pipes) then they can be fed in the proper phase to
give gain in a desired direction.  There are other sorts of wire arrays
(like a Bruce, half square, or bobtail curtain) that could be hung below
the eaves of your roof without attracting much attention.


Beyond that, it would help to have more specifics to understand the
cause of the problem.  If there is a bit of a hill blocking your path to
that particular repeater, then a nearby ham may be able to set up
a cross-band repeater you could use to listen to it.

Does the repeater have an EchoLink or other mode?  You can listen
to the audio through that, and transmit on your radio to make a
response.

Have you checked that your coax losses aren't too high?

Can you determine how much the signal strength varies in your area?
Do others in your area have the same problem?
When you go mobile, how far do you have to travel to get a good signal?

I find a good first step is to determine how much gain you need to hear
the repeater well.  This is where I suggest a home-built (cheap!) yagi that
you can test with, even if it means sitting on the roof, to see if that size
is adequate.  If you need 7 elements to have enough signal, then worrying
about how to mount a 3-element beam is counterproductive, because it
isn't going to help you (although a pair of 3-element beams might work...)

If the check-in sessions are in the evening, then at least for part of the year
you can use a telescoping support that you run up after dark to make your
check-in, then take back down before dawn.


And sometimes a particular repeater is just too weak to hear well given
the antenna you can manage in your circumstances.  Then all you can
do is to call up a friend and listen to the net through his phone.

WA3SKN

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Re: Options for mounting a small 2 meter Yagi
« Reply #33 on: July 29, 2022, 03:23:21 PM »

He does not need the gain, he needs to shield his antenna from the local noise source.  There is a good possibility that some aluminum foil placed at the right location could resolve the issue.

-Mike.
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KK4GMU

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Re: Options for mounting a small 2 meter Yagi
« Reply #34 on: August 18, 2022, 05:46:10 AM »

Quote from: KK4GMU

The S meter reads 2 when the repeater is NOT transmitting.  It reads 3.5 when it IS transmitting.  The meter on my 7100 goes up to 60.

On the RSP/SDR (for some  reason I cannot post the screen shot now) there is a narrow (maybe 5 MHz wide) spike at 145.320 from the noise base of 137dBm to 130dBm.  I'm not sure how significant that is.


Quote
OK, that indicates that the signal is weak.  But you can see that whatever
background noise is reading 2 when the repeater is not transmitting may
be making it difficult to hear:  if that were zero instead, the repeater
signal would be further above the noise floor.
As I mentioned elsewhere, my S2 noise is a DRAMATIC improvement over what I had -S9 - and voice is very copyable - and I am ecstatic at those levels.  But strangely, the noise does occasionally pop back up to S9 or a little less for a few hours.  I haven't tracked the time and exact duration. As I write this, non-receive noise is at S4.5.  It ranges from S2 to S9 and inbetween from one day to the next.  Ideally I'd create an Excel table and track the S levels based on time of day, relative humidity, cloud cover or not, rain or not, etc.

Quote
The bandwidth and filter settings in the radio might make a difference.
Yes, setting the IF filter to 2 or 3 on my IC-7100 makes a BIG improvement, as does tweaking my CLRdsp.

Quote
I would also test it with a temporary moveable antenna to see if the
signal strength changes significantly when you move around the yard
or on the roof.  With multipath, a foot or two can make a significant
difference.  I'm not convinced that is the issue, but it is a simple check
to make.
 
I did that and it make no discernable difference.


Quote
Have you checked that your coax losses aren't too high?
I did.  My 145.330 SWR are near 1.0 - straight shot of 60' of LMR-400

Quote
Can you determine how much the signal strength varies in your area?
Do others in your area have the same problem?
When you go mobile, how far do you have to travel to get a good signal?
Within several hundred feet around my house signal strength is the same.
A fellow ham 6 block away (1/4 mile) has no noise.  Another 2 miles away has similar noise as I have on 145.330. I have not gone mobile.  That is a good test I have yet to do with a fellow mobile ham.

Quote
I find a good first step is to determine how much gain you need to hear
the repeater well.  This is where I suggest a home-built (cheap!) yagi that
you can test with, even if it means sitting on the roof, to see if that size
is adequate.  If you need 7 elements to have enough signal, then worrying
about how to mount a 3-element beam is counterproductive, because it
isn't going to help you (although a pair of 3-element beams might work...)

If the check-in sessions are in the evening, then at least for part of the year
you can use a telescoping support that you run up after dark to make your
check-in, then take back down before dawn.

And sometimes a particular repeater is just too weak to hear well given
the antenna you can manage in your circumstances.  Then all you can
do is to call up a friend and listen to the net through his phone.
With the IF filter setting at 2 or 3, the CLRdsp, the vertical antenna raised up to 25 feet instead of 15 feet, and the noise that now fairly often (and inexplicably) goes below S9, I have decent copy on the 145.330 net.

I can live with that.
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K0UA

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Re: Options for mounting a small 2 meter Yagi
« Reply #35 on: August 18, 2022, 03:31:04 PM »

Quote
The S meter reads 2 when the repeater is NOT transmitting.  It reads 3.5 when it IS transmitting.  The meter on my 7100 goes up to 60.

On the RSP/SDR (for some  reason I cannot post the screen shot now) there is a narrow (maybe 5 MHz wide) spike at 145.320 from the noise base of 137dBm to 130dBm.  I'm not sure how significant that is.

Extremely significant. This explains everything. This explains why you can get into the repeater but do not hear it well.  Judging by the frequency, this is almost surely leakage OUT of your cable TV service. Even if you don't subscribe to it, it is possible that your neighbors do. This is usually channel 18 in the old cable channel numbering scheme, but I would not count on that without knowing more about your cable system. It is possible that a good smart cable TV troubleshooter could find the leakage and solve it. Or not. Of course it could even be leakage in your own home. Or not.
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73  James K0UA

KA4WJA

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Re: Options for mounting a small 2 meter Yagi
« Reply #36 on: August 19, 2022, 12:43:22 PM »

1) WOW, Jerry, I really wished you'd have mentioned this (all of this) earlier....like 6 months ago.  :)

And, btw...I do not regularly scan this "antenna restrictions" forum....actually almost never do....just came here today looking for something and saw your thread here (recognized your callsign and had a look see....and what-do-you-know, you put more info in here in "antenna restrictions" regarding your interference than you did in RFI or other posts?), and you included here in this thread, some extremely important info (that I and others have been asking for now for months)...

The S meter reads 2 when the repeater is NOT transmitting.  It reads 3.5 when it IS transmitting.  The meter on my 7100 goes up to 60.

On the RSP/SDR (for some  reason I cannot post the screen shot now) there is a narrow (maybe 5 MHz wide) spike at 145.320 from the noise base of 137dBm to 130dBm.  I'm not sure how significant that is.


2)  And, please take note of a change I'm making here/now in this posting....I'll now be referring to your "interference" rather than calling it "noise".....sure, on FM it sounds like noise, but I don't think it is....I believe (with ~ 95% certainty) it is interference, or to be more precise, RFI....(this is why I've been asking for months to know what it sounds like in SSB, CW, or AM!  'Cuz if we'd had that info, things would have been a whole lot easier....AND, if I'd had known you had an SDR this could've been solved months ago...LOL)
But, no worries....we'll get you pointed in the right direction now!  :)


3)  Dale, WB6BYU, et al,

Fyi, to let you all know, I've been in contact with Jerry, KK4GMU directly for months now....trying to help (while I am 200 miles away caring for elderly family, I do still technically live/work there, in Jerry's city, just ~ 15 miles away from him and know a fair amount about the area, the repeaters [especially my own 6.97 at 1000' AGL], etc...) and I've been unaware that he even had a RSP/SDR, let alone had done any noise tests, other than mentioning the "noise" he receives on this one FM repeater (never got a report on SSB, CW, or AM, nor that there was any "spike" or any significant rise in noise across the band)...so, I've been quite hindered in the past....BUT...



4)  But, now, with this new info, I'm ready to make a few determinations!   I just really wish this was in the RFI Forum, not in "antenna restrictions" forum!  but, oh well....that's life, huh? :)

a)  Jerry, I'm fairly certain that some of the older areas of your community (On-Top-Of-The-World), such as Friendship Colony, have cable TV services provided by Spectrum (and internet, as well?)....(and, I think the "basic cable" is provided in "bulk" via your association fees?)   But, some of the newer areas do not have "cable TV", but rather have fiber and provide streaming and live-tv from BridgeNet communications.   Please understand that I do not live there, and haven't been in there (in your gated community) in many years....so, I'm going by my old info.....but you should be easily able to confirm all of this yourself in less than a couple minutes, yes?

b)  Cable TV services (whether if they are digital or analog, or a combination of both) use VHF TV frequencies as well as low-band, mid-band (where 2m lies), upper band, super-band, etc. "Cable TV Frequencies", sent via coaxial cable.

c)  "Cable Egress" (the cable TV signals radiating out of the cable system) can be a real pain in the butt....it can be as simple as one bad connection / splitter, etc., or a many bad connections, or bad cable/wiring itself...or even simply bad design/installation.

d)  Some of the worst cable egress comes from a user (yourself or a neighbor) connecting other things in their home to the cable TV cable/wiring (even a "distribution amp" in an attic or behind an entertainment center, etc., can cause issues)...since some cable service doesn't always include all the local channels that some users desire, they connect "rabbit ears", etc., to their TV and the cable-tv service at the same time!  And, this means that the rabbit-ears become the transmit antenna for cable-tv channels, radiating all-over-the-place!  :(  This is a real problem in some areas, 'cuz some of the multiplexed-local-broadcast-TV channels are not well-distributed and not carried on many cable-TV systems....so, it could be as easy as finding your's or a neighbor's rabbit-ears connected to the cable system, and disconnecting them, and/or using a switch (cable-tv A/B-switch)....or....{or, if the neighbor insists that he have absolute-seamless TV, you should be able to make it all work by making sure there is a nice splitter [hybrid-splitter/combiner] that gives 25 - 30db isolation between the adjacent ports, combining these two signal paths....not the best approach, but will usually suffice}

e)  There are other possible sources of this interference, but for the moment let's assume the cable TV service (and/or internet service, if coming from Spectrum) in your area and/or in your building (or even in your own home) is the proximate cause of your interference!   {I'm 95% sure of this, so let's go down this road for a short-ride, and think the skies will open wide! :) }


5)  After many months, my initial "1st / best advice" is still the same:  we need to find the source of the interference!  (and, just like over the past few months, this is really up to you....whether you do it yourself, or have some assistance....this isn't something that can be done over the internet)

a)  First off, a quick question....Do you, yourself and/or your neighbors in the same building, have Spectrum TV and/or internet?

If you/they do (my guess is yes), find where it enters your own unit and/or where it enters the building to feed all the units there.....this is usually a small pedestal or wall-box....{you're unlikely to be able to access the cable there, but you can easily use your TH-F6a handi-talkie near-by --- perhaps even taking the antenna off, or partially unscrewed, to reduce the interfering-signal level, if needed....use your TH-F6a to "sniff out" that locale to see what the signal level is there}


b)  If you're lucky, the interference there will be strong!  (stronger than in your backyard near your antenna)  If this is the case, a few phone calls to Spectrum should get a resolution!   You will need to complain to them about the interference, and insist that they come out and do a cable-egress-survey!  Remind them that you are in the ILS approach path of an airport (you are close) and their cable-egress is not only illegal, but it may cause an airplane to crash....sure, this is unlikely, but they don't know that!    And, afterward it's likely that you'll good-to-go....BUT...  (but, for areas with underground utilities / underground cable tv, this is usually not the case....in these locales, usually cable-tv-egress / cable-tv-caused-RFI comes from the "subscriber premises", meaning your house / your neighbors' houses! :( }


c)  So, if you find the interference is not stronger there at the cable entrance / cable splitter location (or even weaker, there), you will need to look inside your own home....and, if you still cannot find a stronger signal than you have in your backyard / near your antenna, then you should walk around your neighbor's houses and talk to your neighbor's.....and yes, I would still call Spectrum and complain about the interference, and still insist that they come out and do a cable-egress-survey!  (just that the outcome of that survey might not solve the interference issue, as the source might be inside someone's house...)



6)  Jerry, as I've been saying now for months, there is a lot more to all of this....and, the more info we have the better (the easier it is to determine the proximate cause of the interference, and point you to the solution!)

For now, the above should get you pretty close to finding the source and at least being aware of the solution....but, you will need to do some of the work, too.  :)

And, FYI....here are some examples of what a spectrum scan would show if you were looking at TV signals on a spectrum analyzer....if you have SpectrumTV and/or SpectrumInternet service in your home, connect the Spectrum TV cable to your RSP-SDR and have a look-see!  Then after you see what is there, tune in to the 2-meter band ---- looking at more than just 145.33mhz --- look at approx 140mhz up to 150mhz [it should look something like the images below in "c"....but, if they have analog TV channels, it will look like the image below in "a"....and if Spectrum in your locale is providing both analog and digital TV signals then it would like both... :)] and then (without changing the frequency) disconnect the cable tv cable from your RSP-SDR and connect your 2-meter ham antenna to your RSP-SDR, and see what you have....is the interference still there?  (it will be a LOT weaker on your antenna, but should still be there?)  If it is still there, we have determined with 95% certainty that your RFI/"noise" is cable-tv-egress!

a)  In the old days, we had analog NTSC-TV signals.....some older analog/digital cable systems still use channels 2 - 13 as analog channels, and some even still used channels 2 - 22 as analog channels....but, these-days, it's doubtful you'll find any old analog TV signals on that Spectrum system, but if you did, if you looked at a 6mhz wide scan, they'd look like this (with the "video carrier" at 145.250mhz):




b)  BTW, a decade or so ago, we had both analog and digital over-the-air TV signals, and they looked like this....I added the red arrow showing the digital ATSC off-air TV signal (notice the ATSC pilot carrier, that is not used in cable-tv QAM systems, so you would not see that coming from your Spectrum cable), and the blue circle around the analog NTSC off-air TV signal:




c)  Now if you have one large "bump" in the spectral display....that sort-of rolls off a bit at 144mhz and 150mhz (or if these are on some other freqs, let me know)...and then the next "bumps" start above an below this....the display would look similar to this:



And this:


Sorry...these are NOT scans of SpectrumTV, and certainly not Spectrum Ocala / Spectrum On-Top-Of-The-World....these are just some scans I pulled off the internet in the past minute or two (and I then added the red arrow and blue circle in "Paint", and reposted them here for you to use as examples ONLY


7)  To sum-up...
As I've been saying for months now, there is a lot to all of this and with the limited info provided here it's been difficult to ascertain exactly what you've been doing / what interference you have...but we have stuck with you, and it's looking like we have got you pointing in the right direction now...

And, if you do the tests I highlight above (and report your findings back here), and we're correct in our assumptions that it is cable-tv-egress (CATV-Egress is how we abbreviate it), then it is up to you to call the cable company (Spectrum ?) and force them to solve this (be sure to remind them that they do NOT have a license to transmit/radiate on those frequencies, but you DO!)

FYI, most experienced hams would've heard this "noise" and figured this out in less than one minute....yep, no BS....and, I'm not bragging here, nor poking fun at "new hams"....nope, not at all!
Rather I'm trying to point out to not just you, but everyone that reads this, that while tracking down RFI can be a pain, it is infinitely easier if you have all the details, and/or you pass on all these details to those you're seeking assistance from!!! :)

{now, how ignorant am I going to look if it turns out that my "95% certainty" is all wrong?  oh well, at least I'll learn something, huh?}


I do hope this helps....and I do hope you'll report back your results, and not just allow your current lower level of interference be "acceptable" and please don't "just live with it"!

73,
John,  KA4WJA


P.S.  No matter if you eliminate your RFI completely or not....if you'd like to try a directional antenna (as I've been saying, is always a good idea), please don't buy a poor-design off of Amazon, but look at a decent small yagi (while INnovAntennas are well known for clean patterns and low side-lobes, they are pricey....so, a 4-element Cushcraft/MFJ would be good, or a 3-element HyGain/MFJ, etc....or maybe a small M-squared....just not a "Diamond" yagi!)
 
« Last Edit: August 19, 2022, 01:07:11 PM by KA4WJA »
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KK4GMU

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Re: Options for mounting a small 2 meter Yagi
« Reply #37 on: August 21, 2022, 09:10:26 AM »

1) WOW, Jerry, I really wished you'd have mentioned this (all of this) earlier....like 6 months ago.  :)
I  would have reported it if I knew but I didn't.  But based on my SDR's spectrum display, that spike doesn't encroach at all into the received repeater frequency.  But I guess it DOES explain when I narrow my IF filter the repeater signal clears up somewhat.  I'd post a screenshot if eHam.net allowed on my end.
« Last Edit: August 21, 2022, 09:30:59 AM by KK4GMU »
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KK4GMU

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Re: Options for mounting a small 2 meter Yagi
« Reply #38 on: August 21, 2022, 09:13:12 AM »

Quote
The S meter reads 2 when the repeater is NOT transmitting.  It reads 3.5 when it IS transmitting.  The meter on my 7100 goes up to 60.

On the RSP/SDR (for some  reason I cannot post the screen shot now) there is a narrow (maybe 5 MHz wide) spike at 145.320 from the noise base of 137dBm to 130dBm.  I'm not sure how significant that is.

Extremely significant. This explains everything. This explains why you can get into the repeater but do not hear it well.  Judging by the frequency, this is almost surely leakage OUT of your cable TV service. Even if you don't subscribe to it, it is possible that your neighbors do. This is usually channel 18 in the old cable channel numbering scheme, but I would not count on that without knowing more about your cable system. It is possible that a good smart cable TV troubleshooter could find the leakage and solve it. Or not. Of course it could even be leakage in your own home. Or not.

I go with the "or not" part about it being leakage in my own home because one of my tests was disconnecting EVERYTHING, including my cable modem and router cables as well as my main electric breaker to the house.  The noise  on the S meter remained the same during that test.
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KK4GMU

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Re: Options for mounting a small 2 meter Yagi
« Reply #39 on: August 21, 2022, 10:02:13 AM »


a)  Jerry, I'm fairly certain that some of the older areas of your community (On-Top-Of-The-World), such as Friendship Colony, have cable TV services provided by Spectrum (and internet, as well?)....(and, I think the "basic cable" is provided in "bulk" via your association fees?)   But, some of the newer areas do not have "cable TV", but rather have fiber and provide streaming and live-tv from BridgeNet communications.   Please understand that I do not live there, and haven't been in there (in your gated community) in many years....so, I'm going by my old info.....but you should be easily able to confirm all of this yourself in less than a couple minutes, yes?
Yes, this area has underground electric (Duke) and cable (Spectrum).  As I mentioned earlier, I disconnected all power and cables inside my house and got the same level of "interference." I suspect I have fiber since my download speed is 302.9 Mbps unless cable now gets those speeds.  Don't know for sure.

Quote
a)  First off, a quick question....Do you, yourself and/or your neighbors in the same building, have Spectrum TV and/or internet?

I am in an attached unit in a building with four units. Neighbors likely have Spectrum, too.

Quote
If you/they do (my guess is yes), find where it enters your own unit and/or where it enters the building to feed all the units there.....this is usually a small pedestal or wall-box....{you're unlikely to be able to access the cable there, but you can easily use your TH-F6a handi-talkie near-by --- perhaps even taking the antenna off, or partially unscrewed, to reduce the interfering-signal level, if needed....use your TH-F6a to "sniff out" that locale to see what the signal level is there}

b)  If you're lucky, the interference there will be strong!  (stronger than in your backyard near your antenna)  If this is the case, a few phone calls to Spectrum should get a resolution!   You will need to complain to them about the interference, and insist that they come out and do a cable-egress-survey!  Remind them that you are in the ILS approach path of an airport (you are close) and their cable-egress is not only illegal, but it may cause an airplane to crash....sure, this is unlikely, but they don't know that!    And, afterward it's likely that you'll good-to-go....BUT...  (but, for areas with underground utilities / underground cable tv, this is usually not the case....in these locales, usually cable-tv-egress / cable-tv-caused-RFI comes from the "subscriber premises", meaning your house / your neighbors' houses! :( }

c)  So, if you find the interference is not stronger there at the cable entrance / cable splitter location (or even weaker, there), you will need to look inside your own home....and, if you still cannot find a stronger signal than you have in your backyard / near your antenna, then you should walk around your neighbor's houses and talk to your neighbor's.....and yes, I would still call Spectrum and complain about the interference, and still insist that they come out and do a cable-egress-survey!  (just that the outcome of that survey might not solve the interference issue, as the source might be inside someone's house...)

For now, the above should get you pretty close to finding the source and at least being aware of the solution....but, you will need to do some of the work, too.  :)

And, if you do the tests I highlight above (and report your findings back here), and we're correct in our assumptions that it is cable-tv-egress (CATV-Egress is how we abbreviate it), then it is up to you to call the cable company (Spectrum ?) and force them to solve this (be sure to remind them that they do NOT have a license to transmit/radiate on those frequencies, but you DO!)

I'll work on the above suggestions, thanks. 
Just to note:  On my IC-7100, right now (Sunday 1:00pm) with the IF filter on 3 (narrowest), "interference/noise" on 145.330 is S1.5.  With the filter set at 1 (widest), "interference/noise" is S3.5.  Those "noise/interference" levels are right now at their lowest. They often range higher, up to the S5 - S9 level.  Nothing I am aware of in the house causes that variation.

Quote
FYI, most experienced hams would've heard this "noise" and figured this out in less than one minute....yep, no BS....and, I'm not bragging here, nor poking fun at "new hams"....nope, not at all!
Funny! ;D
I look at "experience" on a scale of 1 to 10.  I suspect you are a 10.  When one achieves that level, most others can appear, well, quite incompetent. :o
« Last Edit: August 21, 2022, 10:04:28 AM by KK4GMU »
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KK4GMU

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Re: Options for mounting a small 2 meter Yagi
« Reply #40 on: August 21, 2022, 10:09:55 AM »

With regard to this turning into a noise thread...

It started out as a question about whether a Yagi in my attic would overcome my "noise/interference" problem. Most replied that I would be better off keeping my outside vertical, and extend it a bit higher if possible.

Still others gave additional advice concerning my REASONS for considering a Yagi - to overcome noise.  From then on, in addressing those additional noise-related questions and suggestions, the thread morphed into "noise/interference" solutions.
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KK4GMU

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Re: Options for mounting a small 2 meter Yagi
« Reply #41 on: August 21, 2022, 11:52:04 AM »

Oh, and all other 2 meter frequencies have roughly the same noise level as 145.330.  So I wouldn't be as quick to conclude it's the small spike near that particular frequency that raises the "noise/interference" floor on that frequency.

While it is "fun" >:( :( :o to troubleshoot "noise/interference" issues, up to a point, there comes a time in every noobish hams life when he accepts what he has and gets on with all the other parts of haminess.
« Last Edit: August 21, 2022, 11:58:25 AM by KK4GMU »
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KA4WJA

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Re: Options for mounting a small 2 meter Yagi
« Reply #42 on: August 21, 2022, 12:32:33 PM »

Jerry,
1)  No worries OM....as I've been saying for decades, none of us were born with this knowledge!  :)

BTW, in the past I've used the term "unknown unknown's" (borrowed this from Rummy, years ago) to try to convey just what we hams trying to help (especially those hams trying to help "on-line", 'cuz on-the-air is SO VERY MUCH easier!) face ---- the guy with the problem / seeking assistance many times doesn't know what they don't know.  :) 

Make's troubleshooting difficult.  Do-able, but difficult...
Which is why I keep always asking for more info....(and, I haven't the time here to explain that what you see on your rsp-sdr as a signal that doesn't encroach, might actually be your interfering signal....a rsp-sdr is not a pro spec analyzer and is not your IC-7100, either....but, since I still don't what your interference sounds like in SSB or AM mode, nor what your cable-tv/internet system's spectrum looks like, nor what your interference itself looks like....well, as I've been saying, you haven't given us much to work with.)

EDIT:  Just saw your latest post...where you think I'm a "10"?  :)
Thanks!  I'm flattered....and my ego wants to just reply that I'm an "11"! 
But, the fact is, there is much more to this than "experience"...it's more about understanding, analyzing, applying, and expertise than "experience"....sure I've got the experience, but so do many folks....it's how you process/learn from that experience, how you use (how well you use) that experience to instantly analyze every situation you face, NOT just look for the specific things you know / you've experienced, but rather applying your experience/knowledge/expertise in areas that are "unknown" to you...THAT is where I excel!
 I majored in Physics and some of classmates were smarter than me...but that was about "knowing things"....in my engineering classes we learned how to apply some of these "things"...but still dealing a lot with knowledge and engineering problem solving...what I've learned, over the years, is much of problem solving, efficient / successful problem solving anyway, is not just about knowledge ("knowing things") nor even just about experience ("doing things"), but rather is "knowing how things work" and "being able to pull from many many pieces of knowledge and many many experiences, and apply all of these quickly to the problem at hand"....and this is especially true in field engineering, where you're presented with a problem and need to analyze it NOW (not in an hour, but NOW!) and have a solution in 5 minutes (usually have a solution as soon as your read an email or read a report...now even 30 seconds later, but RIGHT THEN AND THERE! 


I  would have reported it if I knew but I didn't.  But based on my SDR's spectrum display, that spike doesn't encroach at all into the received repeater frequency.  But I guess it DOES explain when I narrow my IF filter the repeater signal clears up somewhat.  I'd post a screenshot if eHam.net allowed on my end.

2)  BTW, while using a narrower filter will improve S/N (in systems that are not thermally-noise-limited), fact is, it does have negative effects as well....just saying, if you get rid of the interference you'll be MUCH better off!


3)  As for not being able to post images?
Not sure why that would be....are you on some sort of eham "probation"?  :)

Maybe you should just reread this:
https://www.eham.net/community/smf/index.php/topic,96198.msg750126.html#msg750126



4)  As for the Cable-Egress not being from your own house....that's possibly (probably?) true, but from how you describe things, this is not a certainty! 

I go with the "or not" part about it being leakage in my own home because one of my tests was disconnecting EVERYTHING, including my cable modem and router cables as well as my main electric breaker to the house.  The noise  on the S meter remained the same during that test.

If you have disconnected your cable-tv/internet coaxial cable feed into your house, on the outside / outside wall-box / at the pedestal, and you found no change in your interference level, then yes you can be assured that your interference is not coming from the cable-tv/internet system inside your own house....but, if all you did was disconnect the "boxes" inside, while this eliminate the "boxes" and associated cables downstream from them from being a proximate cause of the interference, it does not eliminate the other cable-tv/internet wiring/splitters/amps/wiring inside your house from possibly being a source of your interference....

This is similar to hams switching off a UPS, or turning off their TV, etc., and thinking that they're "off"....when they need to be turned off AND everything unplugged from them....this is also similar to unplugging a cable-modem and thinking it is off, when some of them (like mine down here) have a built-in battery-back-up system (a dedicated UPS)...

Fact is, you get close in these instances, and sometimes that good enough....sometimes it's not.  :(


5)   Further, and most importantly.....you need to do some of the things that many of us have been wondering about for months now...

a)  Do you have a completely digital cable TV system?  (yes, I know it is marketed as such, but is it actually all digital QAM TV, or are there analog TV signals there as well?  you can see this on your TV set, not the cable box/modem....or even better use the rsp-sdr that you apparently have...and that you've not mentioned before.)

b)  What cable tv channels are in mid-band, especially catv channel 18?  (not "channel 18" on the box, but actually catv channel 18....which runs from 144mhz to 150mhz...)

c)  What does your interference sound like in SSB or AM?  (again, something I've been asking for months)

d)  What does your interference look like on you rsp-sdr?  (wished I'd have known you had this months ago)

e)  And, very importantly, you should ask some questions of those folks that you pay your money to....ONTOTW themselves, your HOA, Spectrum, etc....and find out some things / ask for a cable egress survey, etc...do not take no for an answer, they work for you / you are their customer, abd Spectrum doesn't have a radio license to transmit on those frequencies, YOU DO!

f)  And....I realize that you said that you will never speak to your neighbors about this and I'm not saying that you must....but, understand that you might actually need to at some point....
AND...



5)  And, to be real blunt here....I've been trying to pry information out of you for months now....and, if you're unwilling to go further and actually find out what is going on / where your interference is coming from....and you're now comfortable simply accepting what you have there, then I do wish you well and wish you great enjoyment in the Amateur Radio Service, but I just don't have the time to spend on a problem that the owner finds is no longer a problem.
So, it's up to you now, Jerry....you do the work and report back....or not.  :)

73,
John,  KA4WJA
« Last Edit: August 21, 2022, 12:55:13 PM by KA4WJA »
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KK4GMU

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Re: Options for mounting a small 2 meter Yagi
« Reply #43 on: August 22, 2022, 02:44:55 PM »

John:

No, I am not under a "ban."

To repeat my previous post just before yours, above ...

Quote
All other 2 meter frequencies have roughly the same noise level as 145.330.  So I wouldn't be as quick to conclude it's the small spike near that particular frequency that raises the "noise/interference" floor on that frequency that is the primary culprit.

And...

While it is "fun" >:( :( :o to troubleshoot "noise/interference" issues, up to a point, there comes a time in every noobish hams life when he accepts what he has and gets on with all the other parts of haminess.

However it came about, my primary goal of getting readable copy on that particular frequency has been accomplished.  Fini.  I'm done with this particular issue.  Thanks for your interest and great effort.  There are other parts of the hobby I enjoy more.
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IC-7100, RSPdx, AT-D878UVII-Plus HT, TGIF Spot

KA4WJA

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Re: Options for mounting a small 2 meter Yagi
« Reply #44 on: August 23, 2022, 01:14:56 PM »

Jerry,
You're very welcome!
And, no worries here....I got the message....you have no further interest in this matter.  :(

However it came about, my primary goal of getting readable copy on that particular frequency has been accomplished.  Fini.  I'm done with this particular issue.  Thanks for your interest and great effort.  There are other parts of the hobby I enjoy more.

And, btw, thanks back to you as well.
Next week, I was going to drop off a 4-element Cushcraft yagi (already tuned for ~ 145mhz) that you could paint any color you desire and use as long as you needed to (years? decades?), it's my test antenna....old, but in perfect shape (kept in my garage), but this saves me the drive. 


73,
John,  KA4WJA
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