Why does Daly City PD come in so poorly even in San Mateo County?

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LIScanner101

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From the 10th floor of the Crowne Royal Hotel in Burlingame I can hear all the local UHF PD/FD action, and, surprisingly, most of the San Jose stuff booms in loud and clear! But for some reason, Daly City PD comes in weak. Are they operating at a compromised location or on low power?
 

russianspd

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Some departments that have their own antenna or tower only produce enough power and coverage to be able to cover within their city limits. I know that with Tracy PD here in San Joaquin County I can just about hear them anywhere I am at and they are a south county agency and need only coverage about the side of Lodi.
 

jland138

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One other possibility is that, because some departments on the Peninsula share frequencies, Daly City is configured to protect Foster City. Daly City's PD primary is Foster City's PD secondary. Don't know for sure, but it would make sense for Daly City to send more of their signal off San Bruno Mountain towards Pacifica since that's a very active travel route between the coast and Daly City.Foster City has a high site at Crystal Springs off 280 in addition to at least one other site in town.

For example, listening to Brisbane near the bay in south San Mateo county is pretty much impossible since both Brisbane and EPA share the same primary frequency.
 

mmckenna

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A few things to consider:
Radio coverage can be expensive. Tower space, antenna systems, etc, all cost a lot of money. An agency is really only interested in providing sufficient radio coverage for its jurisdiction, nothing else. Sending RF energy outside the area of intended coverage is a waste, putting that power into the right areas helps with building penetration, something that is much more important to the radio users.

FCC licenses also define the area of operation, usually shown as xx kilometers radius around point y. Exceeding that can cause interference to other users on the same frequency, so the FCC can sometimes reject a license application if the transmitter power/ERP and antenna height don't add up to something that makes sense from an interference prevention standpoint. In the case of Daly City, the mobiles are licensed for 40km around the transmitter sites, which does cover Burlingame, but that 40km isn't a requirement.

Radio operation outside the jurisdiction for mutual aid purposes often happens on other channels that are specifically designed for wider area coverage. Spending money on providing radio coverage outside the normal area of operation isn't a good investment.

Radio systems are designed to cover their licensed area, there is no requirement that they provide entertainment to scanner listeners, no offense intended.

Being in a hotel doesn't mean much, which direction your room pointed does. A 10 story hotel is going to be concrete and steel, with lots of wire, pipes and energy efficient glass, all things that are not conducive to RF.

San Jose has to cover a much larger area than Daly City, and their location puts them at an advantage, too. They have several sites high up that look up the bay. Looking down the bay at San Jose from a 10 story hotel in Burlingame isn't much of an issue. Some of the mountain top sites above San Jose have a clean shot up past San Francisco. On a clear day I can be up there and see the bridges and well up past Mt. Tamalpais.


They do have a site on San Bruno Mountain. If you plot the location using the coordinates on the FCC license, you will see that they appear to be just west of the crest, and their antenna is only shown as being 15 meters off the ground, so that doesn't really put them in a really good place to shoot down into Burlingame, although I bet they do.

I'd really suspect the building you were in as a big part of the issue. Penetrating concrete, steel and low-e glass can be problematic.
 

LIScanner101

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mckenna,

I think your post hits everything right on the head. I tend to stay on the south-facing side of this hotel so I can listen to the bulk of the Bay Area Peninsula, so it's understandable that places "behind" me (such as Daly City) don't come in so well because instead of just penetrating e-glass the Daly City transmissions have to do that PLUS go through walls, concrete etc before they even touch my antenna.
 

rooivalk

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They used to have the ability to turn repeaters on or off, depending on where the PD units were located.
 

LIScanner101

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mystery solved...

I took a ride to the Daly City PD today and now I understand why it comes in so poorly from Burlingame. The PD is located deep in a small valley and is surrounded by local government buildings. In addition, the antenna is located atop a strange-looking concrete "obelisk" which is not very tall to begin with.
 

KC6SVW

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The antenna at the PD is a receive antenna only. The main transmitters are on San Bruno Mountain low on the tower to protect Foster City PD-2. Daly City is not simulcast since San Bruno Mountain pretty much covers the entire city but both channels are voted.
 

gusbuster

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I'm up by 280 and Millbrae Ave in Millbrae. If I choose to, I will hear them just fine with my Hand held.


Nobody mentioned this but I'm assuming that you are using a portable unit? 10 story and a lot of concrete will block reception.

Not an expert, but it screws up cell phone reception, why not radio signals?

John
 
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