New to Scanning - Gonna Use an Antenna

[KmattFPS]

Hello,
Just had a quick question. I purchased 2x RTL-SDR V5 from Noolec. Will this work inside at all? Or am I oversimplifying this? From my understanding I could simply plug them into my computer, download the drivers and use SDRTrunk with some Radioreference imports to listen. (I understand how to setup the software) just not what hardware will be needed.
My desktop is in a room somewhat near a window. I don't know if that will help at all. I can also use my laptop and stick the antennas out of a window.

I might be dumb and completely wrong. Please let me know haha.

Thanks.

 

[Hit_Factor]

Antennas need to be matched to the frequency you wish to monitor.

Buying a great big, high gain antenna might be a mistake if you just want to hear a public safety system.

Tell us roughly where you are and what you want to listen to.

 

[KmattFPS]

Antennas need to be matched to the frequency you wish to monitor.

Buying a great big, high gain antenna might be a mistake if you just want to hear a public safety system.

Tell us roughly where you are and what you want to listen to.

I'm in the Red Deer AB Area.

I want to listen to Red Deer County Fire (Which is on P25 Phase 1), Lakeside EMS & Sylvan Lake Fire Department Dispatch. Lakeside EMS & SLFD are non-digital.

Maybe some ATC if I'm bored.
PS: The 2 things I bought come with 3 antennas each.
Telescopic antenna mast (variable frequency)
433MHz (ISM) antenna mast (fixed frequency)
UHF antenna mast (fixed frequency)

 

[KmattFPS]

Posts lots of sync loss on P25. On Non digital it's all static or mostly. I put 99.9 in and I can somewhat hear it, but mostly static.


Wondering what the best approach is here?

 

[wtp]

for reception only, there are no antenna rules.
try them all and figure out which one works for you.
i am close enough to one tower the a paperclip works.
to look a little bit better i go out with a race antenna that is 2 inches tall.
my county uses a trunked system and there are 6 towers so no problem with a signal.

 

[Whiskey3JMC]

Posts lots of sync loss on P25. On Non digital it's all static or mostly.

Focus on frequency band rather than voice mode when dealing with antennas. An antenna doesn't care if a signal is P25, DMR, analog. Are said P25 & "non digltal" on different bands? (VHF vs UHF vs 700 or 800mhz)

 

[G7RUX]

for reception only, there are no antenna rules.

This is not really true.

Antennas are reciprocal devices, so characteristics for transmit are reflected in receive performance and vice-versa. This means that gain, mismatch, radiation patterns, etc have the same importance for both receive and transmit.

Of course, a mismatched antenna on receive will just lead to a potentially deaf system whereas the same performance on transmit might well cause excess heating in transmitter power amplifiers. Antennas designed specifically for reception only, such as active antennas may not be suitable to transmit through but this does not change the basic parameters for the actual antenna element(s) itself.

So my point is this: a properly tuned (if resonant) antenna with low mismatch loss will likely perform well, and definitely better than the same antenna used off-tune, etc. Just because anecdotal information indicates that a paperclip "works as a receive antenna" does not mean it works well.

 

[KmattFPS]

Focus on frequency band rather than voice mode when dealing with antennas. An antenna doesn't care if a signal is P25, DMR, analog. Are said P25 & "non digltal" on different bands? (VHF vs UHF vs 700 or 800mhz)

Yes. The non digital freq are 172.260, and 155.385 (static). I also tried 462.125, that was idle but gave off "fade" The digital P25 frequencies I was talking about were 772 (also idle, no fade, just idle and sync loss)

My understanding is all the idles happen to be UHF frequencies. While VHF is the ones that are static.

The UHF frequencies get no signal, while VHF is getting strong signal on SDRTrunk. Yet it's static. So my understanding is something is interfering with the VHF signals, and then something is just completely wrong with my setup that's preventing UHF from working.

 

[G7RUX]

Wondering what the best approach is here?

You will *always* get the best performance from an antenna designed for the frequency/frequencies you wish to receive. Using an antenna for the "wrong" frequencies will result in poor performance and possibly no reception at all. Most antennas are single or dual band but you can get pretty good "wide band" antenna designs like the discone; this will give reasonably OK performance over quite a wide range of frequencies so this might be a reasonable route to take for a general-use outdoor antenna.

From your pictures, the first is just noisy (wrong antenna?) and the general noise floor looks rather high, the second is just silence so it looks like completely the wrong antenna and/or there is nothing in range and the third looks like decent, reasonably clean wide-FM broadcast signals.

 

[KmattFPS]

You will *always* get the best performance from an antenna designed for the frequency/frequencies you wish to receive. Using an antenna for the "wrong" frequencies will result in poor performance and possibly no reception at all. Most antennas are single or dual band but you can get pretty good "wide band" antenna designs like the discone; this will give reasonably OK performance over quite a wide range of frequencies so this might be a reasonable route to take for a general-use outdoor antenna.

From your pictures, the first is just noisy (wrong antenna?) and the general noise floor looks rather high, the second is just silence so it looks like completely the wrong antenna and/or there is nothing in range and the third looks like decent, reasonably clean wide-FM broadcast signals.

Yet the third one is static.

 

[dave3825]

Your first pic shows too much gain.




Second shows not enough gain and or no signal seen.




Third pic, FM radio is 200 mhz wide and is WBFM which I do not believe SDRTrunk can do.

 

[kh6idf]

In the 3rd picture you have your gain set to 36, which is really low. Try setting it to automatic and see if that helps. The first picture looks like you are picking up a lot of noise - the noise looks like 'snow' on an old analog TV. I think you are using one of the antennas that came with your SDR(s), try to move it away from the computer or better yet put it outside of a window and see if the noise decreases and you can start to see the signal you are looking for at 172.250.

I am about 2 weeks ahead of you, I have two Nooelec V5's and am running SDRTrunk. I have everything working now.

 

[KmattFPS]

In the 3rd picture you have your gain set to 36, which is really low. Try setting it to automatic and see if that helps. The first picture looks like you are picking up a lot of noise - the noise looks like 'snow' on an old analog TV. I think you are using one of the antennas that came with your SDR(s), try to move it away from the computer or better yet put it outside of a window and see if the noise decreases and you can start to see the signal you are looking for at 172.250.

I am about 2 weeks ahead of you, I have two Nooelec V5's and am running SDRTrunk. I have everything working now.

I have the antenna sitting on a window sill, I can't open the window as it's -20 C outside.

This is what I see now:Gain is automatic. Sometimes it lights up as control for maybe a second. (with all control freqs entered on the channel)

Only one freq

 

[kh6idf]

Looks like your control channel is showing up now at least. Here's what my screen looks like currently. When SDRTrunk locks onto the control channel the status will change to orange and say CONTROL instead of IDLE. Sometimes it takes a few minutes for it to lock on if the signal is a bit weak. But your control channel looks good (red) and there's not too much noise so it SHOULD lock on pretty quickly.



My control channel is on a tower not too far away so it's strong. I can actually receive it with just the coax laying on the floor inside (with an occasional error). I'm using a dual band rubber duck antenna outside about 10 feet away from the house and 4 feet high:

 

[KmattFPS]

Ugh. So what am I doing wrong?

Messages tab shows lots of these:

2025:01:09 06:30:23 APCO-25 0 NAC:2278/x8E6 VSEL2 MSG:0484B9223F8685427F0772535A82C588A6950714844A64A4BD00000000002154B3B3F9DFFCE699285032954E844C1ABE62FEC8242986B8200A318BFCBB09F211EA40A6CA2E850000000000955CECEF4A1FE321E4A142DC55BA110688228BE14B9C8B888A88B2C0800022208824888A222885A000000000025575F5FF72FFB4D31A850E7557E90519A6AA13A56C420E06490D2C62F3CBFA0B2482624998A8B780000000002154F3D3FDDFF3D36D2A5030B547A0545E732516F0140D9A002435BD8BDFFB193A7121E52242A2D8000000000085
As well as a many many sync loss messages.

 

[dave3825]

Ugh. So what am I doing wrong?

Gain is automatic.

Sometimes it lights up as control for maybe a second. (with all control freqs entered on the channel)

You would be better of manually adjusting the gain to where you can see the signal. Most cases auto does not do good.

You also should increase the freq rotation to 1000 or so. Will keep the dongle tuned to each control channel and gives it more time to lock on.

 

[KmattFPS]

You would be better of manually adjusting the gain to where you can see the signal. Most cases auto does not do good.

You also should increase the freq rotation to 1000 or so. Will keep the dongle tuned to each control channel and gives it more time to lock on.

View attachment 175992

Okay. It just constantly rotates through each frequency.

 

[kh6idf]

You could also try removing all the control frequencies except for the one that you know looks good, that way it will just sit on that frequency and keep trying. I have two control frequencies listed for my tower and I've never seen it use anything except for the one you see in my screenshot.

I agree that automatic isn't always the best value but it can show if there is a signal there, and you can reduce it once you see the signal to reduce the noise level. Start at the highest gain (495 I think) and reduce it to get rid of as much noise as you can as long as the control channel still looks strong enough (and it locks on).

 

[KmattFPS]

You could also try removing all the control frequencies except for the one that you know looks good, that way it will just sit on that frequency and keep trying. I have two control frequencies listed for my tower and I've never seen it use anything except for the one you see in my screenshot.

I agree that automatic isn't always the best value but it can show if there is a signal there, and you can reduce it once you see the signal to reduce the noise level. Start at the highest gain (495 I think) and reduce it to get rid of as much noise as you can as long as the control channel still looks strong enough (and it locks on).

I just don't get it. Why won't it lock on!

 

[kh6idf]

Is it a simulcast system? You have it set to LSM. If it isn't, try changing to C4FM (channels tab in Playlist Editor).

It looks like Red Deer 1 is NOT simulcast to me, so make that change to C4FM, save it, stop the channel and start it playing again. That might do it.