SDR for LAPD/LAFD

[chainsawman]

If I place an SDR within city limits for LA would I be able to pick up all of LAPD and LAFD? I believe I would need 3 dongles tuned for the 506-507 and 484 range for LAPD and one tuned for 857-860 for LAFD.

From what I can see, divisions that broadcast in the 506-507mhz range have a bunch of repeater towers so I believe I would be able to pick those up super easily from almost anywhere. However, I see some divisions like in the 484 range only have a single tower? Does that mean to pick those up I'd have to place a radio relatively close?

 

[ladn]

If I place an SDR within city limits for LA would I be able to pick up all of LAPD and LAFD?

You're going to have to be more specific as to location. "LA City Limits" covers a large, geographically diverse, territory. And, not to pick nits, but it's not so much as where you place the SDR as where you place the antenna (and the antenna's characteristics).

 

[AM909]

You sure you don't also want LA County and CHP, whose jurisdictions are scattered around the LA area? This is one of the most complex areas for radio in the world.

 

[chainsawman]

You're going to have to be more specific as to location. "LA City Limits" covers a large, geographically diverse, territory. And, not to pick nits, but it's not so much as where you place the SDR as where you place the antenna (and the antenna's characteristics).

Thanks for the reply! The antennas are these Bingfu that will be placed indoors near an apartment window in the Downtown LA area.

 

[ladn]

Thanks for the reply! The antennas are these Bingfu that will be placed indoors near an apartment window in the Downtown LA area.

Those antennas will be ok for UHF/800 MHz (but not great). Mount them on a pizza pan or cookie sheet to give them a useable counterpoise (groundplane).
Your building may shield some reception and simplex coverage will likely be compromised. Also expect a fair amount of electrical noise from pretty much everything in the vicinity.

 

[chainsawman]

Those antennas will be ok for UHF/800 MHz (but not great). Mount them on a pizza pan or cookie sheet to give them a useable counterpoise (groundplane).
Your building may shield some reception and simplex coverage will likely be compromised. Also expect a fair amount of electrical noise from pretty much everything in the vicinity.

Oops, I meant to link these 400-520mhz Bingfu for LAPD specifically. Would those work better? Got any recommendations for better indoor antenna?

 

[ladn]

Oops, I meant to link these 400-520mhz Bingfu for LAPD specifically

Not really much of a difference as far as receiving. LAPD is on UHF-T band and LAFD is 800 Mhz. Using a pizza pan or cookie sheet as a ground plane under the antenna will help some.

Some users have had very good results with the Larsen tri-band antenna (Pulse Larsen NMO150/450/758 Tri-Band Antenna). You'd also need the Larsen NMO magnetic mount. This will be a bit pricier.

I'd try the Bingfu antenna first. Which SDR are you using?

 

[chainsawman]

Not really much of a difference as far as receiving. LAPD is on UHF-T band and LAFD is 800 Mhz. Using a pizza pan or cookie sheet as a ground plane under the antenna will help some.

Some users have had very good results with the Larsen tri-band antenna (Pulse Larsen NMO150/450/758 Tri-Band Antenna). You'd also need the Larsen NMO magnetic mount. This will be a bit pricier.

I'd try the Bingfu antenna first. Which SDR are you using?

Thanks! Super helpful advice. I'm using this Airspy Mini for LAPD. I believe I'm going to need the R2 for LAFD though.

 

[marcotor]

The only way you will know for sure is to set it up and find out what you can hear. We can guess and speculate, but knowing how high up you are, which direction the antenna is facing, what things might be in the way, it's hard to say with any certainty. LA is a rich, dense jungle of RF crammed with traffic pretty much 24/7.

And is it that important to hear every Division in the City?

 

[Edwardthephotographe]

If I place an SDR within city limits for LA would I be able to pick up all of LAPD and LAFD? I believe I would need 3 dongles tuned for the 506-507 and 484 range for LAPD and one tuned for 857-860 for LAFD.

From what I can see, divisions that broadcast in the 506-507mhz range have a bunch of repeater towers so I believe I would be able to pick those up super easily from almost anywhere. However, I see some divisions like in the 484 range only have a single tower? Does that mean to pick those up I'd have to place a radio relatively close?

YOU ONLY NEED 1 DONGLE!! Hope you havent made the purchase yet. You can run LAPD with SDR SHARP and the "Simple APCO 25" plugin. Everything is done in the SDR Sharp program, no need to run additional applications etc. LAFD is simple, conventional 800mhz. you should be able to pick up all the repeated channels just about anywhere in LA as they utilize a linked repeater system, transmissions are repeated across all repeaters. LAPD on the other hand dosent do that. Repeated transmitions only go through the local repeater(s), so South LA will not likely be heard in the valley etc. Lasty its not so much about close, but more about line of sight, especially at UHF and 800. For example from where i am in Burbank, I can pickup airplanes on the ground at LAX even over the 2000 ft mountain in the way. This is do to the lower freqency, but i have trouble with LAPD Devonshire, and Valley Traffic due to the location of the repeater, and the hill in the way. I reccomend investing in a good antenna system, I use a D3000n for all my recievers.