Noob- General question on radio scanning

[alokpant]

Hi, I am very new to radio and this may be elementary question, though I cant find answers by searching this forum. I am using use SDR radio (SDRPlay RSPDx, SDRUno) to scan and listen to some local frequency ( utility, HAM radio etc). I try most of the frequency listed @ below but hear nothing. Can you be kind enough to educate me on below as example
1. Is this Freq 154.96500 in Mega hertz. ie. 154,965,000 Hz
2. What does Type mean RM, BM etc mean. I get its Repeater, Base, Mobile etc. but does this include specific decoder type etc that I need to tune in my SDR for specific type AM/LSB/USB,.. NFM etc. Do I need to configure Tone value (ex. 110.9PL etc) in SDR application to hear
3. What does Mode FMN means. Is this FM, NFM mode?
4. Are these digital or analog. Do I need special app such as DSD+ etc to hear this
5. Is there any other database other then below to help list local frequency and type of broadcast

Any other pointers to share for starters like me
Thanks you for your help
AP

Travis County, Texas (TX) Scanner Frequencies and Radio Frequency Reference

Scanner Frequencies and Radio Frequency Reference for Travis County, Texas (TX)

www.radioreference.com

Frequency	License	Type	Tone	Alpha Tag	Description	Mode	Tag
154.96500	KLX853	RM	110.9 PL	Austin Fire Disp	AFD Station Alert (with TG 1147)	FMN	Fire Dispatch
155.34000		BM	CSQ	Medevac-Hosp	Medevac to Hospitals	FMN	Hospital

 

[devicelab]

1. Yes
2. Repeater/Mobile..? Base/Mobile..? This doesn't matter for the most part
3. Scanners ignore the PL Tone and will receive the frequency no matter what; however, on the repeater input frequency (and with certain tones) you may hear a slight hum which is the embedded tone. (I believe most scanners filter 0-255 hz on the audio going out to the speaker -- so these were not audible.) If there's no tone, then that's CSQ. i.e. the transmitting carrier will unlock the repeater instead of the PL Tone. The SDR will receive the raw audio. This is one way to identify repeater inputs -- you'll hear the PL tone.
4. If there's a PL TONE then it's always analog. The mode should say P25, DMR or NXDN if digital.
5. Always -- finding this info is the trick -- hence, the reason for the web site. You can always search the FCC database by frequency or licensee name.

 

[greggk]

Alokpant, Are you still with us?

 

[alokpant]

Thankyou devicelab, I posted a reply to this thread earlier with pictures but seems it didnt go all the way. I will attempt to repost the picture. Essentially, I am still stuck and not sure if this is due to some configuration miss, my indoor antenna or just a lack of knowledge. I am using SDRUno, with SDRPlay RSPdx SDR and Tram Tram 1411 Broad Band Discone/Scanner Base Antenna Antenna.


I can hear local FM/AM radio broadcast. I can also get ADSB (dump1090) working; and I can use GNUradio with my RTLSDR to decode garage door and car key fob signal. But that's all.

I am more or less stuck on listening to any digital/HAM signal etc

a) I tried most of the local frequency from here (Austin Metro Area Scanner Frequencies and Radio Frequency Reference) and all I see/hear is noise. Unclear if I need to switch to AM, FM, LSB, USB with NFM etc. I am not sure if the signal is week or I am using incorrect type/mode setting. Any suggestion which specific frequency I should focus on that most likely work.

b) I try to sniff ACARS signals per this document (https://www.sdrplay.com/docs/SDRuno_ACARS.pdf). I see no signal at 131.550MHz and wonder if I am trying wrong frequency (or Antenna). I am in Austin, TX area

c) I try to decide APRS signal per this document (https://www.sdrplay.com/docs/SDRuno_APRS.pdf) Again no luck. Is 144.390 right frequency at my area. Am I trying to scan at wrong time (evenings..) or I am too far out

Any recommendation to try listning to any known frequencies in Austin area that can work with MultiPsk / digital+. I am having no luch here and noone to really talk.

I very much appreciate this community and sharing insight. Thanks again for taking time


Sincerely

 

[devicelab]

Well I would start with 162.55 Mhz or whatever NOAA Wx station is valid for Austin.

My guess would be that your gain settings are not set correctly in SDRUno? Also, it's possible to have too much gain.

If you watch this video here:

@2:16 in the video, in the upper left, you'll see the gain settings. Also [obviously] make sure you're using the correct antenna input.

He's using a lot of gain in this video so you'll probably want something like 19 db or so -- since your antenna should provide you with plenty of gain. Start with the middle slider setting and go from there. If you have to too much gain, then you may need to use the MW/FM notch button. This helps to reduce the gain of AM and FM broadcast stations -- which can cause problems. You'll see this instantly when adjusting the gain setting and you start seeing spikes everywhere. Generally, it should be fine to use the MW/FM notch filter all the time since local broadcast stations will still be seen by the SDR.

Yes, HAM frequencies are NFM and I'm pretty sure ACARS is as well. APRS is also NFM. ACARS should be heard but there's more than one frequency so you should watch the spectrum and see which one is active in your area.

First things first and make sure you get the SDR working properly. If you're not seeing NOAA weather radio then you have a problem. You'll likely see several stations around 162 megs.

 

[greggk]

You're welcome. LOL

 

[bill4long]

Yes, HAM frequencies are NFM... APRS is also NFM.

Incorrect. You can hear FM (16K0F3E) using NFM (11K2F3E), but hams are generally transmitting FM (16K0F3E.)

 

[devicelab]

Incorrect. You can hear FM (16K0F3E) on NFM (11K0F3E), but hams are transmitting FM (16K0F3E.)

Sorry it was a long day at work. FM/NFM for digital and normal FM for voice.

 

[bill4long]

Sorry it was a long day at work. FM/NFM for digital and normal FM for voice.

Starting up SDRuno, and I think you were right the first time. They are calling 16K0F3E "NFM". But that's non-standard.

 

[alokpant]

@devicellab, Thankyou. Yes I can hear NOVA weather channel fine (attached). Its 162.400.000 . Its somewhere with local HAM that I am not able to hear

@Bill Not sure I know what 16K0F3E, 11K2F3E means. Can you please elaborate

Can you please help suggest how to decode the info @ The Austin Amateur Radio Club Inc - Repeater Info
Dont know what input tone means or +/- means

Frequency (MHz)	Input Tone	Comments
146.780 (-)		Open repeater - D-Star only
146.880 (-)	107.2	Open repeater - FM and C4FM
146.940 (-)	107.2	Open repeater - FM
224.800 (+)		Open repeater
440.650		Open repeater - D-Star only
444.100	103.5	Open repeater - Echolink via WA5YZD
444.200	107.2	Open repeater
1248.100		Open simplex - D-Star Digital data only
1293.100		Open repeater - D-Star only

Similarly not sure what to make of below-
What does the Offset means here. Also is this analog sound or do I need DSP+, MultiPsk etc (if so what kind of decoder etc)

https://www.repeaterbook.com/repeaters/location_search.php?state_id=48&type=city&loc=Austin

Click on a header to sort.​

Frequency ▾	Offset	Tone In / Out	Location	County	Call	Use
53.6700	-1.0 MHz	103.5	Austin, UT Austin	Travis	WB5PCV	OPEN
145.1100	-0.6 MHz	103.5 / 103.5	Austin, Westlake Hills	Travis	N5ZUA	OPEN
146.6100	-0.6 MHz	103.5 / 103.5	Austin	Travis	WB5PCV	OPEN

 

[nd5y]

+ and - after a repeater frequency is the offset.

Offset - The RadioReference Wiki

wiki.radioreference.com

If you are only receiving then the offset is irrelevant.

16K0F3E amd 11K2F3E are Emission Designators.

Emission Designator - The RadioReference Wiki

wiki.radioreference.com

Its somewhere with local HAM that I am not able to hear

If you randomly tune to ham frequencies don't be surprised if you don't hear anything.
They can be dead for hours or days. They don't have continuous transmissions like commercial broadcast and NOAA weather stations. Ham repeaters usually have lower power and lower antennas than most BC and PLMR stations.
Not having a good outdoor antenna will further reduce your chances of hearing ham repeaters.

 

[devicelab]

The SDRUno software doesn't decode digital data such as D-STAR or C4FM. You would need 3rd party software for that.

As nd5y suggested, if you're not seeing any signal on the above frequencies, then they're probably just not being used. Scan the amateur voice band from 145 - 148 Mhz and see what you find. You may need to be persistent. Also scan 440-445 Mhz.

Sadly, no one has (yet) designed SDR software to "scan a frequency range for any active signals and then tune to that frequency" -- that would be a neat feature.

Don't worry about the emission codes -- that's just what the FCC uses to define what is NFM, AM, WFM, etc.

 

[jonwienke]

Sadly, no one has (yet) designed SDR software to "scan a frequency range for any active signals and then tune to that frequency" -- that would be a neat feature.

Not true: SDR# Frequency Scanner Plugin Updated

 

[devicelab]

Not true: SDR# Frequency Scanner Plugin Updated

No you didn't understand my feature request. I'm not talking about scanning programmed frequencies. I'm talking about the SDR software able to detect a RF signal and tune automatically to that frequency.

So a user would say program a range of 145-148 and that's it. Then the software would tune automatically to a signal within that range w/o user intervention.

 

[jonwienke]

That is exactly what that plugin does. You can scan a frequency range (say 136-174MHz), and log hits on active frequencies, then scan those hits in the standard fashion later.


If you set the parameters correctly, you can sweep about 10MHz of bandwidth per second--far faster than any scanner.

 

[devicelab]

That is exactly what that plugin does. You can scan a frequency range (say 136-174MHz), and log hits on active frequencies, then scan those hits in the standard fashion later.

Interesting, I didn't know this... I think the first version I saw of this was scanning only programmed frequencies. I'll give it a try later tonight. Thanks.

 

[jonwienke]

Interesting, I didn't know this... I think the first version I saw of this was scanning only programmed frequencies. I'll give it a try later tonight. Thanks.

"The popular frequency scanner plugin for SDR# has recently been updated (in Russian, use Google Translate). The frequency scanner plugin allows you to quickly scan through a definable slice of spectrum, stopping to listen on active signals."

 

[alokpant]

Hi all,
I am new in this area and trying to get familiar with SDR (using RTL-SDR, SDRPlay RspDx ; SdSharp/SdrUno, DSDPlus/MultiPsk). So far I am able to hear analog audio; also able to also hear local P25 radio via DsdPlus+Fastlane as well as track planes (dump1090) etc.

I am now trying to listen to local HAM Radio and APRS signal and not much luck so far

a) How do I listen to local Ham Armature radio talk via SDR.

1. Is there still both Analog vs digital (DMR?) radio. How to look for each?
2. Where do I find the frequencies. I assume the steps are same as F25 (Am I right?); I think I just need to find the right frequency. I am lost on the various database in radioreference. There is one @ Texas Scanner Frequencies and Radio Frequency Reference Also looked here https://www.repeaterbook.com/repeaters/location_search.php?state_id=48&type=city&loc=Austin
   1. I can find some signals in those range but not sure how to know what kind of decode logic to apply
3. How do I look/scan for local Ham radio. Is there some scanner to look for active Ham.
4. Is Dsdplus+fastlane still the right software?

b) To listen/see to APRS radio, I tune to 144.39MHz but I dont see much signal; its at noise level. I tried neighboring signals but no luck (@ So my question is

1. Is the APRS use infrequent (bad timing) for the absence?; or the use is very common and I should see/hear the signal
2. Is it possible APRS is on different frequency at my location. I am in Austin, TX
3. How wide are APRS? I can scan neighboring frequencies but not sure how to identify it. None of the nearby signal look like this(Automatic Packet Reporting System (APRS) - Signal Identification Wiki)
4. Does repeater forward those signals or the radio device. Any idea why can't I get those signals
5. Are there other options beyong MultiPSK to decode APRS signals

c) What is the right non-expensive Antenna type to track APRS, armature radio

Thanks again

 

[alokpant]

@devicelab and @jonwienke - Thankou again for help and taking time. Very much appreciated.

When I scan between 144M - 147M, there are two frequency that have continuous signal. Both of these have distinct signature; However I am not sure what type and I can't decode it (I am using SdrUno with virtual audio redirection and piping to dsdplus).
Please see attached signals. Do these appear familiar; Can I hear it via DsdPlus

 

[alokpant]

BTW Also attached is the signal I capture @441.3M. On left I have SDRUno settings (see B-Audio) and on the right DsdPlay (see the audio setting). I hear or see nothing special. No activity on DSD+