tonydi
Member
I've listened to the CHP on this channel for ages and today I noticed that I can only hear the dispatcher side, nothing coming back from the units. Does anyone know if they've made a change or why this is happening?
CHP Golden Gate San Jose 42.500
- Thread starter tonydi
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The San Jose mobile frequency is 42.280Mhz. I don't believe that they have a repeater so mobiles except for car-to-car traffic would not be on the base frequency. Or, not very much.
ridgescan
Member
I was monitoring the entire Bay Area CHPs in the 42-43megs Friday and base/mobiles were both on 42.500 base frequency, as it usually is when I hear them. Upon seeing OP's thread I just put it on and sure enough, no mobiles. I'm wondering if it's a weather-related downed repeater?
Some CHP offices use repeaters, but most do not. Mobiles will be line of sight only. The Diamond D130J has poor response at 42Mhz. Yes, I know they say 25-1300Mhz. They lie. The stock whip is tuned to 6 meters. A 48 inch whip moves the resonance down to 42Mhz.
The discone part of the antenna covers about 100-1300 (maybe). The whip makes up a base loaded ground plane but is tuned to 50Mhz. Lousy performance on CHP.
The CHP radio system is designed for their convenience using remote bases (not repeaters) for the most part. It is not designed for scanner users.
The discone part of the antenna covers about 100-1300 (maybe). The whip makes up a base loaded ground plane but is tuned to 50Mhz. Lousy performance on CHP.
The CHP radio system is designed for their convenience using remote bases (not repeaters) for the most part. It is not designed for scanner users.
ridgescan
Member
Thanks for the fact of not using repeaters. I receive every CHP agency in the Golden Gate region, both bases and mobiles. The line-of-sight thing with mobiles right here on 42.760 get pretty scratchy on the 785D but nice and clear on the R8600 albeit weaker on the meter.
Like I said before, when listening to San Jose on 42.500, I always got base/mobile copy no problem just like the OP said he did "since forever".
Anyways, I think the D130J does alright with CHP in my opinion. What more could I expect from a unity gainer-I'm happy with it. Some of those guys are 40-50 miles from here.
I normally monitor the Aqua here in the Bay Area (Hayward, Castro Valley) and usually the mobiles are rebroadcast on the Aqua output, like a repeater. There are times when they do have equipment failure. Also, I believe the dispatcher has the discretion whether to use this function or not. I"m sure it will come back if it already hasn't.
ridgescan
Member
I monitored the GG region for the last half-hour. Here are my observations. Base/mobiles heard on the following BASE frequencies:
MAROON
GRAPE
AMBER
PINK
AQUA
VIOLET
TURQUOISE
BRONZE
RUBY still no mobiles heard, only base.
Nothing at all heard on KHAKI or EMERALD (are these two still in use?)
Also heard base only on 42.340 which is supposedly statewide AC frequency.
MAROON
GRAPE
AMBER
PINK
AQUA
VIOLET
TURQUOISE
BRONZE
RUBY still no mobiles heard, only base.
Nothing at all heard on KHAKI or EMERALD (are these two still in use?)
Also heard base only on 42.340 which is supposedly statewide AC frequency.
I"m hearing the KHAKI normal here in Fremont. The dispatcher is working both the AQUA and KHAKI, which is normal. What is odd today, tho, is that the mobiles are only repeated on their respective channel. Usually the Khaki mobiles are repeated on the Aqua as well, and vice-versa, but not this morning.
ridgescan
Member
Funny, I heard base and mobiles both on AQUA probably at the same time you say you didn't.
Historically, dispatchers are on the Base frequencies and Mobiles on the mobile frequencies. A few years ago an upgrade was done where the mobiles are "repeated" back out on the base frequency of the site received from. BUT this function can be turned off at any time by the dispatcher. I hear it turned off, for example, when there is an open mic. It could just be that a dispatcher turned off the repeat function and it hasn't been turned back on. One of the many reasons I continue to monitor mobile (and P25) frequencies.
The Aqua was repeating mobiles that transmit on the Aqua mobile (25 and 143 units), but normally the Khaki mobiles (118) are also repeated, but not this morning. The one dispatcher works both colors.
tonydi
Member
Fascinating info (some of which I don't understand), so thanks to everyone who jumped in here.
I'm happy to report that I'm back to being able to hear the unit's side of the calls so everything is back to normal. I do sense one slight difference in that when the unit releases the mic button I hear this odd sound, like a scratchy fog horn. But hey, I'll take it!
I'm happy to report that I'm back to being able to hear the unit's side of the calls so everything is back to normal. I do sense one slight difference in that when the unit releases the mic button I hear this odd sound, like a scratchy fog horn. But hey, I'll take it!
ridgescan
Member
Still not receiving mobiles here. Are you?
ridgescan
Member
Now today I'm hearing mobiles on base frequency again, which proves what you stated.
Yes the Emerald is still being used, although it's Emerald 4 now. It is Santa Rosa and hearing it outside of the NORTH BAY is rough!
Regards,
-Frank C.
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