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San Francisco Bay Area Discussion - Local area specific discussion for the San Francisco Bay area including the North, East and South Bays.

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  #41 (permalink)  
Old 02-11-2015, 10:03 PM
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whisper16, I'm in the area of Hollenbeck & Fremont. I've been using the 436HP with the only modifications being upgrading the initial firmware to the newest firmware. I use the scanner in the house & mobile with only occasional multipath issues in certain areas that seem to be consistent. The antenna I use is the SpectrumForce 700mhz SMA antenna.
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  #42 (permalink)  
Old 02-12-2015, 12:35 PM
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Default Thank you.

Thanks Stealthguy. I appreciate your response.
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  #43 (permalink)  
Old 02-12-2015, 1:36 PM
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Well, today I heard what SVRCS P25 is supposed to sound like.

First, I put on the famed RS 800MHz antenna, which I just got yesterday. This improved the SVRCS reception and the number of calls received, and also improved reception of all systems (150/460MHz, etc.) across the board. And, it's shorter than my previous antenna. However, the P25 audio was still very garbled and choppy.

Took the 436HP into work, which is in Sunnyvale (I live in Santa Clara near Levi's Stadium) and the result was quite different. Even though I'm deep in an office building with lots of metal girders where even cell reception is bad, I'm able to receive SVRCS Santa Clara PD/FD and Sunnyvale PD/FD clearly. There's still a bit of that digital vocoder/robot sound, but at least it's clear and understandable, with no breakups or distortion or those short pops/clicks I get at home.

When i get home will walk the neighborhood with the RS 800 and see what happens.

Ironic it sounds fine at work, but not at home where I want to listen.

I guess I'm one of those "lucky" folks whose listening location has simulcast issues, with delayed digital data confusing the scanner.
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Old 02-12-2015, 1:50 PM
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Default That's good news

That's great! I know you stated earlier that you didn't want to put up an outside antenna at home, but a Yagi antenna pointed in the right direction may be the answer to your reception issues. Often times they will work even mounted in the attic.
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  #45 (permalink)  
Old 02-12-2015, 2:18 PM
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Originally Posted by whisper16 View Post
That's great! I know you stated earlier that you didn't want to put up an outside antenna at home, but a Yagi antenna pointed in the right direction may be the answer to your reception issues. Often times they will work even mounted in the attic.
Thank you. I see some high-gain 700/800MHz Yagis that are very compact, but the big problem is getting the cable down thru the ceiling, which doesn't look very good. It also limits my scanner to being in one location in the house. The reason I buy portables is to carry them around.

I know, I know, this is what i have to do and there's no choice...

Santa Clara came in so well with a rubber duck before they went P25...
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Old 02-14-2015, 6:21 PM
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Looks like the county Sheriff P25 channel comes in nice for me, not SVRCS. The Sheriff is heavily simulcast, yet it comes in OK.

Looking at trying this out for SVRCS:

Amazon.com: Phonetone 8db Outdoor directional Yagi 800Mhz/850MHz/900MHz GSM Antenna with N female connector for Mobile cell phone signal Repeater Booster Amplifier: Cell Phones & Accessories

It's cheap, so if it doesn't work nothing big lost.

What do you think?
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Old 02-14-2015, 6:57 PM
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i'm not sure it would last long in the outdoor elements, but for the price, go for it. also, there is no specs for the amp. Depending on your scanner antenna connector, you will need an adapter, but the price is cheap enough to take a chance
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  #48 (permalink)  
Old 02-14-2015, 7:08 PM
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i'm not sure it would last long in the outdoor elements, but for the price, go for it. also, there is no specs for the amp. Depending on your scanner antenna connector, you will need an adapter, but the price is cheap enough to take a chance
It doesn't include the amp. Just the antenna.

I will have to use this indoors mounted on a tripod or paper towel holder base, so not concerned about the weather protection.

Ordered an N-male to SNA-male cable.
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Old 02-14-2015, 7:37 PM
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then I thank you will be ok. the amp may cause you more headaches then help. keep your coax run short. good luck.
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Old 02-14-2015, 7:39 PM
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then I thank you will be ok. the amp may cause you more headaches then help. keep your coax run short. good luck.
Thanks. I ordered a 1M cable. I want to see if this directional Yagi will solve my simulcast distortion issue. If it doesn't work, I''ll only have invested about $30.
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  #51 (permalink)  
Old 02-16-2015, 7:11 PM
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I, too, got a BCD436HP in December to hear Sunnyvale & Santa Clara. After some programming hiccups (service types selection!), I was able to hear what I thought was all the talk groups I wanted. But the audio quality was - as described by others - garbled and distorted. That quality varied somewhat by location and proximity to the cities I was monitoring. I really only use the scanner in my car, and I'm using the antenna that came with the unit.

Even the Web-based streaming sites seem to have at least some of the same distortion. I, too, wondered if the PD/fire units were experiencing poor audio, but I'm not hearing anyone voice frustration on the air.

I'll try a different antenna, as recommended above, but any other ideas for changing settings, etc., would be appreciated.
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Old 02-16-2015, 8:19 PM
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hello every one out there in svrcs land. I have been trying to update the library and firmware on my ws1080 on the ez scan program
on an out dated pc
and have had no luck. the pc drive does not recognize the scanner. Today it seemed to have almost worked but then it said too many errors to finish the process. now when i try to browse the library the scanner says database not found on sd card. All of my programming is ok, only the library is gone. I have tried every thing that I can with this pc. Is there anyone that would be willing to met and let me plug into there pc ?
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Old 02-16-2015, 9:16 PM
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Originally Posted by paultv View Post
I, too, got a BCD436HP in December to hear Sunnyvale & Santa Clara. After some programming hiccups (service types selection!), I was able to hear what I thought was all the talk groups I wanted. But the audio quality was - as described by others - garbled and distorted. That quality varied somewhat by location and proximity to the cities I was monitoring. I really only use the scanner in my car, and I'm using the antenna that came with the unit.

Even the Web-based streaming sites seem to have at least some of the same distortion. I, too, wondered if the PD/fire units were experiencing poor audio, but I'm not hearing anyone voice frustration on the air.

I'll try a different antenna, as recommended above, but any other ideas for changing settings, etc., would be appreciated.
Sounds like you have the same issue as i do.

Apparently, we are victims of having the same (strong) signal coming to our radios from two different antennas (one from Sunnyvale, one from Santa Clara). The problem, as I understand it, is that digital data comes from two sources but delayed. Digital radio expects a very specific stream of data, and if it comes from multiple places and delayed, it confuses the decoding and it cannot give you intelligible data. The symptoms are garbled speech, cutting in and out, and pops and clicks. You also miss a lot of calls.

The solution (apparently) is to have a highly directional antenna you can point at one of the antenna towers so it will not receive the other antenna. A Yagi design antenna receives signals from one specific direction but not another. This is what we need.

As I understand it, the PD/FD have receivers/antennas such that this multipath reception is not an issue. It's supposed to be very expensive. I have no idea how they achieve it. I'm an electrical engineer, and honestly I think it's a terrible design. But that's another argument.

I have ordered a Yagi antenna and will point it so it will just receive the Santa Clara antenna and not the Sunnyvale one (I live in Santa Clara) and I will let you know what happens.

The downside is you lose reception of other agencies (Milpitas, MV, Los Altos, etc.) but this is the price you pay.

Go digital, go P25, go APCO (sarcasm).

Last edited by fmalloy; 02-16-2015 at 9:22 PM..
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  #54 (permalink)  
Old 02-16-2015, 9:48 PM
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As I understand it, the PD/FD have receivers/antennas such that this multipath reception is not an issue. It's supposed to be very expensive. I have no idea how they achieve it.
The P25 radio's from Motorola, Harris, etc.. have one thing that no scanner company has been able to recreate. FEC (Forward Error Correcting), in the simplest terms each packet has a unique number and checksum. If a duplicate packet is received it is discarded (not processed).

P25 has been under development since the early 90's. So the makers of the professional radio's have had roughly two decades to test, develop and patent their radio designs. The scanner companies didn't start development on P25 reception until it was widely put into use.

Because of the patents on things like FEC, the scanner companies are really handicapped and can't easily recreate them.
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  #55 (permalink)  
Old 02-16-2015, 11:35 PM
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Originally Posted by fmalloy View Post
Sounds like you have the same issue as i do.

Apparently, we are victims of having the same (strong) signal coming to our radios from two different antennas (one from Sunnyvale, one from Santa Clara). The problem, as I understand it, is that digital data comes from two sources but delayed. Digital radio expects a very specific stream of data, and if it comes from multiple places and delayed, it confuses the decoding and it cannot give you intelligible data. The symptoms are garbled speech, cutting in and out, and pops and clicks. You also miss a lot of calls.

The solution (apparently) is to have a highly directional antenna you can point at one of the antenna towers so it will not receive the other antenna. A Yagi design antenna receives signals from one specific direction but not another. This is what we need.

As I understand it, the PD/FD have receivers/antennas such that this multipath reception is not an issue. It's supposed to be very expensive. I have no idea how they achieve it. I'm an electrical engineer, and honestly I think it's a terrible design. But that's another argument.

I have ordered a Yagi antenna and will point it so it will just receive the Santa Clara antenna and not the Sunnyvale one (I live in Santa Clara) and I will let you know what happens.

The downside is you lose reception of other agencies (Milpitas, MV, Los Altos, etc.) but this is the price you pay.

Go digital, go P25, go APCO (sarcasm).

Not exactly.

LSM(CQPSK) has both AM and FM components. Scanners use a discriminator tap to get the data to the decoder. The problem is that the discriminator tap is on FM only receiver, and blocks/strips the AM component of the CQPSK wave form causing the resultant data to be distorted.

This is not an issue with a C4FM signal that is strictly FM.

The advantage to CQPSK wave form is that in a simulcast system where multiple transmitter are transmitting on the same frequency, the delay tolerance is greater than C4FM. This means that the signals time of arrival can be greater, thus making CQPSK more favourable in simulcast design than C4FM.
Just a note, it is only the infrastructure that transmits in CQPSK, the subscribers transmit C4FM. The satellite receivers are to ensure the talk out and talk in coverage is balanced.


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Old 02-16-2015, 11:38 PM
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Originally Posted by budevans View Post
The P25 radio's from Motorola, Harris, etc.. have one thing that no scanner company has been able to recreate. FEC (Forward Error Correcting), in the simplest terms each packet has a unique number and checksum. If a duplicate packet is received it is discarded (not processed).



P25 has been under development since the early 90's. So the makers of the professional radio's have had roughly two decades to test, develop and patent their radio designs. The scanner companies didn't start development on P25 reception until it was widely put into use.



Because of the patents on things like FEC, the scanner companies are really handicapped and can't easily recreate them.

FEC is part of the P25 standard. See my reply above as to why scanners suck at decoding CQPSK(LSM). Folks only have Uniden/GRE/Whistler to blame for making receivers that are unable to properly decode CQPSK, and Knowing that this waveform is in widespread use. Shame on them.


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  #57 (permalink)  
Old 02-17-2015, 1:30 PM
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Folks only have Uniden/GRE/Whistler to blame for making receivers that are unable to properly decode CQPSK, and Knowing that this waveform is in widespread use. Shame on them.
Wonder how much this would add to the cost of the radio?

An absolute shame. SVRCS seems to come in just great at my office, where I guess I am much closer to the Sunnyvale tower and the Santa Clara tower is not messing up the decode. It sounds fine. At home, where I want to monitor, it's unreadable, even though I'm pretty close to the Santa Clara tower.

Guess a future BCD636HP will have CQPSK support...get your wallets ready...?
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  #58 (permalink)  
Old 02-17-2015, 10:07 PM
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What area do you live in? I'll drive in the area and see if my 436 goes to crap too.
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Old 02-17-2015, 10:09 PM
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What area do you live in? I'll drive in the area and see if my 436 goes to crap too.
Rivermark (community on Agnew and Montague). But I found that other parts of Rivermark can receive SVRCS. It's just that my house is on a particular bad spot.
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Old 02-17-2015, 10:53 PM
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What area do you live in? I'll drive in the area and see if my 436 goes to crap too.
Stealthguy05, as long as you`re driving around,please drive around Lawrence Expressway and Tasman, and see what you come up with, having a hard time with the HP 2, in that area, also the Lakewood Area.
Thanks.
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