Getting into SDR

[far342]

I've been using regular scanners for around a year now and currently have a 325p2, 15x and 75xlt. I've been wanting to get into SDR but I'm not exactly sure where to start. I looked at some of the pages on RTL-SDR.com and I understood some of it but I still have some questions.

The main system I want to monitor is the Oregon SW-7County System (Benton County & Scott Mtn. sites) which is P25 Phase I. I also would like to monitor the OR Statewide System (Scott Mtn. & Wipper Hill sites) which is P25 Phase II. But, the SW-7 system is definitely the most important for me. Aside from that I also listen to a lot of VHF (mainly 150+ MHz). Not monitoring the analog stuff on the SDR isn't a biggie for me since I wouldn't mind keeping that on my Uniden scanners.

1. Are the RTL V3 and V4 the options I should be looking at? And what are the differences between them?

2. What are some of the advantages and disadvantages to certain software options?

3. How does scanning/monitoring work on said software options? Would I be able to program any like a traditional scanner or does it work differently?

4. Would I need to use two dongles for trunking? I've heard of this before but what exactly requires this?

5. What would be a decent simple way of setting up the antenna? All the antennas I have are BNC. Two are rubber ducks, one is an extendable from the 15x and I also have a cheap VHF UHF 800 mobile antenna from amazon that has a long cable and I mainly keep setup at my window. Would that last one be able to work with the dongle if I just had a BNC adapter for it? I ask because my computer is underneath my desk and while I do still pick up the system well on my 325p2 if I put it around that area, I'm sure that could still cause problems if the antenna was under my desk. I also don't feel like setting up an entire dipole antenna (not yet at least)

Thank you in advance

 

[Whiskey3JMC]

1. Are the RTL V3 and V4 the options I should be looking at? And what are the differences between them?

Manuel Compares the RTL-SDR Blog V3 vs RTL-SDR Blog V4

Not too long ago we released our first batch of RTL-SDR Blog V4 dongles, and most have been received by customers now. The next batch is coming soon, and we should be able to start sales again within the next 1-2 weeks from this post. It is incorrect rumors that they are totally sold out forever...

www.rtl-sdr.com

2. What are some of the advantages and disadvantages to certain software options?

What specific "software options" are you looking at? They each have their own strengths and weaknesses, all have their own learning curves. Some run with a few mouse clicks, others require batch files and scripts to run & trunk track properly. DSDPlus decodes D-Star, YSF & NXDN while SDRTrunk doesn't cover those modes

3. How does scanning/monitoring work on said software options? Would I be able to program any like a traditional scanner or does it work differently?

4. Would I need to use two dongles for trunking? I've heard of this before but what exactly requires this?

Again, what apps are you inquiring about? I'd strongly advise purchasing a Radioreference premium subscription so you can utilize Radiorference's web import service. Take SDRTrunk for example, you can easily import info from the RRDB into SDRTrunk playlists. Be sure you have enough RTL-SDRs required to cover the spread of bandwidth for the target system(s) you're looking to monitor. Each RTL covers 2.4MHz of usable spectrum so if you have a trunked system/site spanning more than that spectrum (say...covering 769.xxx to 774.xxx), you'll need an additional dongle to cover the balance. The SDRPlay line covers 10MHz or usable bandwidth so one of these should suffice to cover the aforementioned example.

5. What would be a decent simple way of setting up the antenna? All the antennas I have are BNC.

Pick up SMA male to BNC female adapters for each RTL-SDR you have. The SDRPlay RSPDX, though more costly than the RTL-SDRs has a native BNC port so no adapters necessary if you only utilize port C. Their website says the BNC port is good for up to 200MHz but I've used it without an issue well above that

 

[far342]

What specific "software options" are you looking at?

Honesty not so sure myself. Whatever the main options would be. I've heard of SDR#, DSD+, SDRTrunk.

Each RTL covers 2.4MHz of usable spectrum so if you have a trunked system/site spanning more than that spectrum (say...covering 769.xxx to 774.xxx), you'll need an additional dongle to cover the balance.

Does this apply to every frequency on the site or just control channels? Assuming it's every frequency, the site I want to listen to goes from 770.781 to 774.706 so I would need two RTLs.

When it comes to monitoring all I really need is P25. I'm assuming SDRTrunk and two RTLs would suffice?

 

[dave3825]

Narrow down what exactly you want to listen to the most. The system, the site and about how many talk groups of interest.

To listen to both systems you would need multiple dongles. Just this site spans 5.1375mhz. Those dongles are generally good for 2.4mhz each so you would need 3. Or an Airspy mini which does close to 6 mhz.

16 (10)

016 (10)

Scott Mtn Lookout

Linn, OR

769.16875c

769.70625c

770.68125c

773.54375c

774.30625c

One of the sites you mention on the other system has 453.xxx freqs and 460.xxx freqs so you would need 2 or 3 for that as well. Dsdplus can work with one dongle on any of the systems/sites you mention but your limited to receiving 1 tg at a time.
Unitrunker (phase 1) and SDRTrunk (phase 1 & 2) (with enough dongle to cover the site) can can monitor multiple tg's simultaneously. Trunking Recorder or RDIO Scanner can record and do the playback.

 

[dkcorlfla]

I recently setup a SDR system for P25 and was stunned at how well it works on the very busy Orlando system.

My setup is: Windows 10 offline, Unitrunker 2.1, Airspy SDR. The Airspy easily covers both the control and all the trunks by itself.

The Airspy is hooked up to an outdoor Diamond X30A ham radio antenna and it picks up everything on VHF, UHF and to my surprise 852Mhz.

See if you can setup an outdoor antenna as it will not pickup RFI from the computer monitor and other noisy stuff in the house.

 

[a727469]

I have been researching a lot in this area and definitely not one that I have any real experience. Now for a really dumb question. Are there any current or planned sdr receivers that are fully standalone with screen that provide built in software such as unitrunker, sdrtrunk or similar? Forgetting cost, why couldn’t a radio like the

LAN-IQ SDR​

Or
Malachite DSP2

Incorporate this type of software? What am I missing?
In other words, similar to a uniden sds100 😉

 

[bearcatrp]

I have the LAN IQ. Great receiver. Wider coverage. Can be used as stand alone or hooked up to a computer and use SDR software for a larger screen. Used to own a Icom IC 705. Great SDR transceiver. Just used it for scanning. Better filters. Has P25 phase 1. But with encryption spreading on P25, not really worth it for just receiving anymore.

 

[Whiskey3JMC]

Now for a really dumb question. Are there any current or planned sdr receivers that are fully standalone with screen that provide built in software such as unitrunker, sdrtrunk or similar?

The standalone SDRs you mentioned & that I'm aware of don't have apps to incorporate digital modes (P25, DMR, NXDN, others) or trunking capability natively AFAIK without the use of an external computer. They typically do handle AM, FM, MW, LW, CW, SSB, RTTY, others I might be missing...

 

[far342]

Narrow down what exactly you want to listen to the most. The system, the site and about how many talk groups of interest.

Out of everything, what I want to listen to the most is Albany Police on the SW7 System on the Benton County Site. The Scott Mtn site is only really a secondary option for me when I'm not able to pick up the Benton Site as well. I also listen to Linn County Sheriff Dispatch and Benton County Law Dispatch on occasion but it's mainly Albany I'm focused on.

One of the sites you mention on the other system has 453.xxx freqs and 460.xxx freqs so you would need 2 or 3 for that as well. Dsdplus can work with one dongle on any of the systems/sites you mention but your limited to receiving 1 tg at a time.
Unitrunker (phase 1) and SDRTrunk (phase 1 & 2) (with enough dongle to cover the site) can can monitor multiple tg's simultaneously. Trunking Recorder or RDIO Scanner can record and do the playback.

When it comes to the ORSRP stuff it's mainly just Oregon State Police and misc random stuff. I can go completely fine without monitoring that system, as I can just get the State Police on VHF anyways.