About to dip my toe in the waters

[AK9R]

I'm thinking about setting up an SDR. I've been reading and watching and I think now might be the time for me to get involved.

Here's what I'm thinking about:
1. I'd like to monitor the 2m and 70cm amateur radio bands. I live in a metro area that has a fair amount of activity on repeaters and simplex in those bands and I'd like to see what's going on. So, I'd like to have one "slice" looking at 144-148 MHz and another "slice" looking at 440-450 MHz.
2. Along those same lines, I'm interested in what's going on in the GMRS and FRS world, so being able to see 462-468 MHz would be nice.
3. I'm a railfan, so having a "slice" that looks at 160-162 MHz would be good.
4. Public safety in my area uses a 700/800 MHz trunked P25 system, so I might be interested in trunk-tracking that system.

I assume that I'll need multiple SDRs to do all this. The RTL-SDR v4 dongle looks pretty good as does the Noelec NESDR. Any preference between these two or others I haven't considered? How many would I need? With these RTL chips being bandwidth limited to about 2.4 MHz (?), I assume I'll need more than one receiver.

I'll be connecting the dongles to a Windows 10 PC that I'll be dedicating to this activity. What software should I run? SDR#? I assume that I would need a different software package for the trunktracking.

Thanks in advance for any useful information.

 

[N1FKO]

You should do your own math of course, but I'll point out that one SDRplay RSP will cover the entire 2m band.

(I use three RSPs, one for a 700 MHz site, one for an 800 MHz site, and an old RSP1 for FM/P25 in the 470 MHz band. I use sdrtrunk to feed Rdio Scanner)

 

[KC1UA]

The SDRPlay RSPDuo has two completely independent receivers in it, but when both are used at the same time each receiver is limited to just 2 MHz of displayed bandwidth. Still pretty effective way to do it with one receiver. Other than that I think you would indeed require two.

 

[Dirk_SDR]

Where to start ...
The RTL-SDR Blog v4 and the Nooelec NESDR SMArt v5 are both good receivers, so you can use both for your purpose. If you were interested in HF and below (< 30 MHz), the Blog v4 would be the better choice, because it uses an upconverter for HF.
All frequencies in the VHF and UHF range, you are interested in, can be received with these receivers. How many of them you would need depends on:
1. Permanent reception on all bands in parallel?
2. Using a scanner app: sequential scanning for interesting signals can be done by only one receiver.
3. How many "channels" do you want to listen to in one of your bands at the same time?
4. ....
And: you will perhaps need more than one antenna for your purpose.

 

[tweiss3]

Airspy R2 does 10MHz bandwidth, RTL SDR does 2.4MHz bandwidth. You will end up needing to figure out how you anticipate splitting up what you want to listen to, and what software you want to use.

It appears that you can do a single site of SAFE-T (or multiple if they are both 800 OR 700) with an Airspy R2, but you will probably need more than 1 if you are using RTL SDRs.

Same goes for each separate band, if you want to listen simultaneously. Using Airspy R2s, you would need 1 for 2m ham, 1 for rail, 1 for 70cm ham, 1 for GMRS/FRS/UHF LMR, and likely 1 for 800 or 700 public safety. That totals out to 5 Airspy R2, or nearly 15 RTL SDRs depending on how you lay it out.

You can do all the trunk tracking and single frequency listening with SDRTrunk, and then create individual streams from 1 software instance.

 

[AK9R]

Thanks for the info about Airspy R2. I hadn't looked at them yet.

Ultimately, I'd like to see all this activity in parallel, but probably just listen to one at a time.

Not looking for HF coverage at this time, just VHF/UHF/700/800.

 

[vagrant]

@AK9R - Observing those slices is one thing, listening to whatnot may be like playing whack-a-mole if you jump to select transmissions. Welcome to the SDR waterfall fun, plus the added features of reviewing what may be raising your noise floor and which antenna provides improved dB, etc. I use the SDRPlay RSP2 and whatever v3 and v4 of the inexpensive dongles with phones and tablets.

 

[dickie757]

The first post kinda indicates you want to jump in, rather than a toe to check it out. Grab a [single] higher quality high bitrate rig and jump around the bands a while. When that fun is not enough, add a couple more, or a Tx capable rig. I suspect you have a decently powerful computer? And speakers.

 

[CKnobb]

Just a couple side notes:

The R2 takes a lot of USB bandwidth. I bought one and used it together with an Airspy mini and a Nooelec v5. The Mini and Nooelec stopped working. Tried the R2 with just 1 Nooelec, still took up too much USB bandwidth. So, I've gone back to 4 SDRs (2 minis, 2 RTL-SDR) on a bus, using SDRtrunk & SDR# simultaneously with no issues. The R2 is great with its 10 MHz bandwidth, but it really hogs USB power even on my robust mini PC.

Itead is having a 15% off sale and the Airspy Mini is $88 (vs $99). The minis work great (6MHz).

The Nooelec SDRs work great as well, and for $30-40 you can buy quite a few.

 

[dlwtrunked]

Airspy R2 does 10MHz bandwidth, RTL SDR does 2.4MHz bandwidth. You will end up needing to figure out how you anticipate splitting up what you want to listen to, and what software you want to use.

It appears that you can do a single site of SAFE-T (or multiple if they are both 800 OR 700) with an Airspy R2, but you will probably need more than 1 if you are using RTL SDRs.

Same goes for each separate band, if you want to listen simultaneously. Using Airspy R2s, you would need 1 for 2m ham, 1 for rail, 1 for 70cm ham, 1 for GMRS/FRS/UHF LMR, and likely 1 for 800 or 700 public safety. That totals out to 5 Airspy R2, or nearly 15 RTL SDRs depending on how you lay it out.

You can do all the trunk tracking and single frequency listening with SDRTrunk, and then create individual streams from 1 software instance.

And the Airspy R2 is simple a better receiver. Never had a USB problem (if you do, use decimation). Using an RTL-SDR is not worth doing; owned several different model, use none now--poor performance in comparison.
If you want just HF: Airspy HF+ Discovery.
If you want just VHF/UHF: Airspy R@
If you want both and good performance: then both the above or new model soon to come out.
If you want both and are short on money: the SDRplay models.
If you do not really care much about performance and are really cheap (and waste money till you discover your mistake and spend more on better): RTL-SDR.
Yes, I currently own all of these and have compared.

 

[tweiss3]

Never had a USB problem (if you do, use decimation).

Can you explain this better? I've never heard of it, but I'm assuming its a USB bus/bandwidth compression tool?

 

[dave3825]

Can you explain this better? I've never heard of it, but I'm assuming its a USB bus/bandwidth compression tool?

Quick start guide - AIRSPY

High Performance Low Cost Software Defined Radio Receivers

airspy.com

For those interested in usb bandwidth allocation,

USB Bandwidth Allocation - Windows drivers

This article provides guidance concerning the careful management of USB bandwidth.

learn.microsoft.com

 

[PDXh0b0]

Airspy & sdrplay devices are great, I have both..but don't toss rtl-sdr blogs & and Nooelec's off the list

If your intrest in hf/sw/mw peaks buy and airspy hf+ discovery or one of the sdrplay devices

If you want to utilize 10 mhz of spectrum, buy an airspy r2 or and sdrplay device(and an capable pc) if you want to listen/decode/record multiple frequencies you'll need multiple vfo's and virtual audio cables

If you want to do multiple stuff at the same time, blog/Nooelec is the way to go

 

[dave3825]

I have an Airspy and hackrf running trunked systems and use nooelec dongles in DSDPlus to scout around and also use them in Unitrunker for p25 logging.

 

[StoliRaz]

Itead is having a 15% off sale and the Airspy Mini is $88 (vs $99).

All I have are RTL dongles and was looking for something that may receive better so I'm thinking of grabbing one of these. On Airspy.us it comes to $84.15 which is a good price but I was kind of surprised by the $15 shipping for such a small, lightweight item. So, the 15% off basically equates to free shipping off the previous $99 price. I might still grab one.