Can hear surrounding towns but not my own

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I have SDR# and DSD+ working great and scanning all the surrounding town PDs with the exception of my own town.
I've spent significant time watching the frequency that my town should be coming in at but I receive absolutely nothing. I know they are transmitting as I listened in on an online live feed and they are there but I cant detect them at all..

any suggestions???
 

br0adband

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Have you checked the frequencies you're using against the RR database, just in case something has changed recently? I know the database isn't perfectly up to date constantly but it's generally the best place to start. I'm guessing you have adjusted the ppm for the RTL stick to ensure you're tuned to the exact (or close enough to it within a ppm or two) frequency or frequencies as required because that's a must-do thing with this type of hardware (and obviously the software as well since they work together). It's entirely possible your local system that you're hoping to monitor just enacted some kind of change to their system, I've seen it happen before.

Also, you have to realize that when you feed the audio output from SDR# to DSD+, you're not going to hear any analog audio whatsoever anymore since DSD+ is only capable of passing along the decoded output from the source signal.

Are you located in an area where everything is using digital protocols? If not then that means you've got analog systems to monitor as well and you can't do that with DSD+ in the audio pathway - the only option (if you must keep DSD+ running) is to enable the "Listen" ability in the Windows Recording mixer for the audio device you're using with DSD+ but that means you'll always be hearing the audio from the digital data at the same time, even when DSD+ is decoding to speech.

So, the basic gist is that if you're using DSD+, you can't effectively monitor analog systems at the same exact time without being force-fed that digital signal audio mixed in with whatever DSD+ is decoding whenever that's happening.

Hope this helps...
 

malware

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Have you checked the frequencies you're using against the RR database, just in case something has changed recently? I know the database isn't perfectly up to date constantly but it's generally the best place to start.
Yes.. Also, the alpha tag for the online feed is showing the same freq.. although I'm not 100% sure how alpha tags work so I guess that might not mean anything?

I'm guessing you have adjusted the ppm for the RTL stick to ensure you're tuned to the exact (or close enough to it within a ppm or two) frequency or frequencies as required because that's a must-do thing with this type of hardware (and obviously the software as well since they work together).
Yes.. I used the NOAA broadcast its aligned pretty well. 35ppm

Also, you have to realize that when you feed the audio output from SDR# to DSD+, you're not going to hear any analog audio whatsoever anymore since DSD+ is only capable of passing along the decoded output from the source signal.

Are you located in an area where everything is using digital protocols? If not then that means you've got analog systems to monitor as well and you can't do that with DSD+ in the audio pathway - the only option (if you must keep DSD+ running) is to enable the "Listen" ability in the Windows Recording mixer for the audio device you're using with DSD+ but that means you'll always be hearing the audio from the digital data at the same time, even when DSD+ is decoding to speech.
Yes they SHOULD be all digital but even still, I don't see anything in the waterfall or the spectrum for signal reception. I did turn on the "listen" option in windows recording for a while to see if I could hear anything (noise, beeps or actual voice), even if faint, and I got nothing.

I'm at a loss.. =/
 

br0adband

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And I take it you don't have an actual physical scanner to use to verify things, either. The simplest answer I can give is this: if you don't see activity in the spectrum or waterfall on the frequency or frequencies where that system should be and everything else seems to be working just fine (the other digital systems, the NOAA weather, etc) then that system isn't broadcasting on those frequencies as expected and something has changed, or your RTL stick and SDR# just don't like you very much.

JUST KIDDING... :p

Not sure what to say in your situation other than to verify the frequencies yet again as well as you're able. The spectrum doesn't lie as it will display anything in terms of a radio frequency transmission in progress when there's one to detect, so if there's nothing shown then there's simply nothing there at all on the given frequency or frequencies you're attempting to monitor.

You might consider trying another SDR program as well, like SDR-Radio, HDSDR, etc and see if you get exactly the same results. Might not hurt to reinstall SDR# itself too - I can't even begin to tell you how many times people (including myself, actually) have or have had issues with something that simply cannot be solved with respect to things like this newfangled SDR stuff and nearly given up on it with bad results, but then I figured why not scrap it all and start over again and miraculously things do work the second time around - and sometimes the third, fourth, etc.

Can't hurt, right?
 
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malware

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yeah unfortunately i haven been able to pick up a scanner yet.
Someone reported in a local forum that they can hear the transmissions in that frequency so it doesnt seem to be the case BUT it is a government entity so you never know.
I tried SDR-Radio for a few minutes today and just wasn't having luck with it at all. seemed a little too confusing for me at first.. especially compared to how simple SDR# is and how quick I was able to get SDR# set up. either way I wasnt in the right mind to play with it.

I will try and reinstall everything. Thats an easy enough thing that would be foolish not to try.
 

majoco

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I know this sounds weird, but have you tried moving the antenna? With a fixed repeater and and fixed location for your antenna, it could be that you have found a perfect 'dead spot'. The other towns have a different antenna location so you'll get the signals.
 

ecps92

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Just like using a scanner.
Location, Antenna, Location, Antenna can bame the difference.

Being on one side of a hill, vs where the feed is one the other side, is one example

You could compare (but already indicate you don't have one) how you hear them from the same location via the scanner.

A Good antenna can do wonders, however location also comes into play with interference, paging, NWS, other electronics too



I have SDR# and DSD+ working great and scanning all the surrounding town PDs with the exception of my own town.
I've spent significant time watching the frequency that my town should be coming in at but I receive absolutely nothing. I know they are transmitting as I listened in on an online live feed and they are there but I cant detect them at all..

any suggestions???
 

malware

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I'll move the antenna around the house to see if it makes any difference. If it doesn't I'll hop in the car, try different places and try get another antenna from radio shack
 

br0adband

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Just to ask: are you using the tiny included antenna that came with the RTL stick(s)? If so, those things are basically useless for most purposes and bands, seriously. I made a post in another thread recently giving suggestions on how to "refit" that piece of crap and make it something useful, you can read it yourself here:

http://forums.radioreference.com/software-defined-radio/284522-yep-i-gave.html#post2132684

If you follow that info, you can always get a chassis mount jack of some kind, like a BNC or whatever, then solder that to the end of the cheap coax (it's cheap, but it works to a degree) then you'll be able to attach a decent antenna or at least some extension coax of some kind to a real antenna. If you do stop by Radio Shack the only one worth the money anymore is the telescopic whip for scanners (#20-006) for $14.99 - they charge like $25 for the 800 MHz nowadays too. I remember when the center-loaded telescopic whip was $6.95, the 800 MHz was $14.95, and they had a true telescopic whip many years ago for $9.95 that didn't have a loading coil in it - was awesome and I'm sad to say I lost mine long ago. No wonder they're in trouble and could end up going out of business: same antennas they've been making for decades and they're two-three times what they originally were, that's just not right. :(

Highest recommendation if you're serious about RTL sticks for monitoring is to get a pigtail ASAP so you can attach a "real" antenna of some kind using more standard antenna connectors (F, N, BNC, PL-259, etc). You may be doing this already, I don't know, just tossing the info out there. :D
 
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yeah I'm only using the antenna-wanna-be that came with the stick.. for now..
I did order a mcx to bnc pigtail today and should be here tomorrow.
In the meantime, I'll take a look at your other post and see if I can rig something up..

Also, I moved the computer/antenna to another room and closely watched the spectrum... the chatter is very low in the town so you gotta watch for quite some time to see anything. Thankfully the online feed gives me a good idea of whether or not I missed something.
After closely watching the spectrum, I did notice SOME signal.. around -55-60 db.. .JUST over the floor so I obviously can't pick up anything worthy.

Hopefully another antenna will help but I was looking up some tower information and the closest tower is only about 0.8-0.9 miles from the house.. I'm also about 75-100 feet lower elevation than the tower so I guess its possible I'm just SOL.

thanks for all the help br0adband. I've been reading a lot of your posts and there is a lot of VERY useful information. Thanks!
 

br0adband

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Seems like a fairly weird situation, hope you'll figure it out. With that kind of proximity to a known tower there's just something not quite right going on. Here in downtown Las Vegas I have several DMR/MOTOTRBO sites located on the roofs of a casino or two within a half-mile of my apartment - even closer than your 0.8-0.9 mile site(s) happen to be - and when they're keyed up good lord, talk about overload. :)

I see a swath of intermod spread across the whole spectrum and even several MHz away I know that means they're keyed up and transmitting but I rarely go jumping for the RF Gain slider to adjust it, usually just "ride it out" till it's over I suppose.

Have you done any research into the FCC licensing of that particular agency? You found the tower site but I'm curious to what the transmitting power happens to be - if it's 50 watts or more (even a bit less) there's just no way it's not showing up on your setup unless it's a) a defective RTL stick in some respect or b) desense caused by the severe signal power based on proximity. No way for me to know for certain but even so, it's somewhat rare to be able to pick up stuff from a distance but nearly nothing from the next door neighbor, so to speak. :D
 

malware

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Have you done any research into the FCC licensing of that particular agency? You found the tower site but I'm curious to what the transmitting power happens to be - if it's 50 watts or more (even a bit less) there's just no way it's not showing up on your setup unless it's a) a defective RTL stick in some respect or b) desense caused by the severe signal power based on proximity. No way for me to know for certain but even so, it's somewhat rare to be able to pick up stuff from a distance but nearly nothing from the next door neighbor, so to speak. :D
RR DB is showing 110 for power. Could that be too strong?
 

br0adband

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If it's ~1 mile away from your location, it could be causing an overload in the tuner's front end to enough of a degree where the signal just kinda gets lost and not even showing up properly I suppose. You mentioned putting your hardware in a vehicle and trying from another location, guess it wouldn't hurt to do such a thing and get some distance between you and that tower/transmitter site.

If it's really 110w, and you're really that close (obviously you are), then with a decent antenna you should be seeing peaks on the spectrum close to 0 dB (or even more) based on the RF Gain. The DMR/MOTOTRBO site that I mentioned earlier gives me peaks of about 0 dB when I have my RF Gain set at 7.7 dB (fairly low, I usually use 28 dB but I was doing this just as a test a moment ago) and that's only a 30 watt transmitter according to the FCC license (I'm using a homebrew 1/4 wave ground plane made from an SO-239 chassis jack and coat hangers, btw, works great). It's pretty damned strong, so are several other signals in my area as well but since I'm in the immediate downtown vicinity all the buildings in the area - because of their heights - are peppered with antennas of all kinds for various services so it's to be expected.

So pack up the hardware and take a trip and see what happens. :D

 

malware

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I'm assuming this kind of overload doesn't happen with a real scanner right?
 

br0adband

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It can, sure, because a tuner is basically a tuner in the long run. ;) Scanners are typically better at handling the front end overload and also may have attenuating circuitry built-in that you enable/disable as required which these RTL sticks and similar hardware don't particularly feature outright.

For these devices, you handle it by reducing the RF Gain in the attempt to attenuate the strength of the signal so it's not overloading the receiver front end. Sometimes it helps, sometimes not but it's another one of those "can't hurt to try" things like so many others.

Experimentation is the hands-on way of learning new stuff more so than most anything else.

Here's a simple test: disconnect the antenna from the RTL stick completely, then try and tune in an FM station in your area. If you get a signal to any degree showing on the spectrum for any FM stations, punch in a frequency for that local system - with the antenna still detached - and see if things are different or if it's still just "dead air" on the spectrum.
 

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I'm just curious and trying to understand how an officer's radio works at the house and I can't even see a sign of life for their signal.
I know their radio works because I've had them come to my house and they used the radio.. LOL

ps.. I've tried using 0db rf gain on the SDR as well as mid level and highest level. no difference whatsoever
 

br0adband

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I did say it was weird, didn't I? :D

Have you tried monitoring other systems - and I don't mean just the digital ones, I mean anything in your area in any other bands of operation for any levels of reception? And for those digital ones that you can monitor, what kind of signal levels are you getting on the spectrum and at what RF Gain settings?
 

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yes.. although I dont listen in on them often, I do get them..
the signals I'm getting all vary between -45 -10..
28 rf gain is what i have it set at usually.
 

br0adband

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"Strange things are afoot at the Circle-K..." :p

That's just truly strange indeed. Guess the local PD have found a way to keep you and everyone else from monitoring, it seems. :D
 

malware

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nah. i think the issue is isolated to my setup.
There is an online feed that contains the PD and other people in a local forums mentioned they were able to listen in as well.
so to summarize the issue.. I'm the problem.. LMAO
 
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