CHP Radio Freq. in the foothills!??

Hey guys I have been having a hard time trying to figure this out. I live in El Dorado Hills and listen to the CHP Green - Base and Mobile - Auburn (45) / Grass Valley (42) / Placerville (44) radio frequencies. I have a 15 inch magnetic antenna mounted outside my house. It works fine for all the Sheriff, Cal Fire Camino dispatch/eldo cmmnd/amador cmnd/calstar, but when ever I listen for chp traffic I will hear like once or twice a dispatcher in a conversation with a unit but I wont hear the unit. I know the chp radio setup it kinda of wierd. The funny thing is I tuned into CHP Black 3 - Base and mobile - South Sacramento (112) / Woodland (47) / Rancho Cordova (58) I can hear every conversation. Whats the deal, can somebody help? Thanks

I listen to CHP Sacto (Black I believe) and Grass Valley on the new APCO Phase II channels. RR databse has them listed. Just need a scanner with the capability.

ColinHartigan said:

I have a 15 inch magnetic antenna mounted outside my house. It works fine for all the Sheriff, Cal Fire Camino dispatch/eldo cmmnd/amador cmnd/calstar,

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It's likely your antenna. A 15" antenna is going to be near quarter wavelength on VHF. That would explain why it works well on CDF, etc.
Low band requires a longer antenna, closer to 60 inches or more, to be closer to quarter wave length. Your existing antenna is way too short to work well on the CHP frequencies.

See if you can scrounge up an old CB antenna, it should work much better.

I don't know about the specific channels you are monitoring in the Sacto area, but I do know that CHP dispatchers have the capability to turn on/off the repeat function. It is likely that your local area is not in the repeat mode, therefore you will only hear a mobile on the mobile freq when they are nearby. The Sacto Black sounds like it is in the repeat mode and you are hearing the mobiles being repeated on the dispatch frequency. Hope this helps.

mmckenna said:

It's likely your antenna. A 15" antenna is going to be near quarter wavelength on VHF. That would explain why it works well on CDF, etc.
Low band requires a longer antenna, closer to 60 inches or more, to be closer to quarter wave length. Your existing antenna is way too short to work well on the CHP frequencies.

See if you can scrounge up an old CB antenna, it should work much better.

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Is that why their cars always have really long antennas?

Emoney250 said:

I listen to CHP Sacto (Black I believe) and Grass Valley on the new APCO Phase II channels. RR databse has them listed. Just need a scanner with the capability.

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It shows that chp green has two extenders that are on the p25 system and then the two that are just fm freq. What is the difference between an extender and repeater.

ColinHartigan said:

Is that why their cars always have really long antennas?

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Exactly.
The old vehicles had a 1/4 wave whip mounted off the side of the trunk. It had the ball mount with a spring and the long whip antenna.
Newer CHP installs have a base loaded whip in the center of the roof. It's usually dead center of the roof, black base, black whip.

A better antenna isn't going to hurt your reception, and it should improve it quite a bit. You need one specifically designed to cover this band. Be cautious about "all band" or "wide band" scanner antennas. Most of them are not appropriate for low band monitoring.
An old CB antenna would work well, and you can pick them up nearly free.

Here's what I do ...

I live in Fair Oaks, work in Folsom and monitor CHP Green and all the other area frequencies. When Sacramento went to CAD many years ago, I began focusing more on listening to CHP. To me it is essential to have an antenna designed for VHF low band and to include the CHP MOBILE frequencies in your scan.

It was only a few years ago that 'repeat' of mobiles even became available. I know the dispatchers turn the function on and off at a whim but don't miss mobiles AFAIK, at least when they are within a range that matters. Signals on low band travel great distance though too.

I still monitor 154.905 but rarely pick anything up on it. I also monitor the 700 MHz frequencies that are now used for that purpose, but am more likely to get their signal from their true low band frequency.

Try monitoring CHP on the Placer trunked system. I think that office is simulcast theRe.

mmckenna said:

Exactly.
The old vehicles had a 1/4 wave whip mounted off the side of the trunk. It had the ball mount with a spring and the long whip antenna.
Newer CHP installs have a base loaded whip in the center of the roof. It's usually dead center of the roof, black base, black whip.

A better antenna isn't going to hurt your reception, and it should improve it quite a bit. You need one specifically designed to cover this band. Be cautious about "all band" or "wide band" scanner antennas. Most of them are not appropriate for low band monitoring.
An old CB antenna would work well, and you can pick them up nearly free.

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Where can I get an old CB antenna, and would it work on these freq. (150 through about 169). And would I need to get a bnc connector to hook it up to my scanner. I want something that will work for all my frequencies. Also what kind of cable would I need

It sort of depends on your skill level. You need to be cautious about purchasing used stuff. I was going to suggest finding a used CB antenna at a garage sale or flea market, but that might not be such a good idea. It's easy to find one, but the chances of it being damaged are high enough that it's probably not a good idea for someone who does not have a lot of experience trouble shooting these sorts of things.

In that case, I'd recommend getting something new, it will save you a lot of headaches.
There are a number of options, and others will likely be able to provide some good recommendations.

For a dedicated low band base antenna:
http://www.theantennafarm.com/catalog/laird-technologies-crs-series-4404.html
That should work pretty well on the 150-169 frequencies as well.

You could also do this:
Mobile antenna: http://www.theantennafarm.com/catalog/laird-technologies-c40-695.html
with the base station adapter:
http://www.theantennafarm.com/catalog/laird-technologies-mbcn-7531.html

Either of these antennas will work on the VHF (150-169) range you mentioned. If you plan on using UHF, 700 or 800MHz, you might want to consider one of the discone style antennas that have the center whip specifically designed for the low band frequencies. I'm not a big fan of discones, but some like them.
You can always make your own antenna. With some scrap wire, it isn't too hard.

The type of antenna you decide on depends on what you feel comfortable installing. Some of the low band antennas can be pretty big and need sturdy mounts. Also, any restrictions based on your neighbors should be considered.

As for coaxial cable:
It really depends on how long the cable run is. The longer the cable run is, the more signal will be lost in the cable. If you have a short run, less than 25 feet or so, basic RG-58 would work fine on low band and the VHF band. Anything much longer than that and you need to step up to something bigger. RG-8, while generally hated by most, will work fine for 50 foot runs or so, especially on these lower frequencies. Longer than 50 feet? You really should be stepping up to LMR-400. If you ever plan on going into the higher frequencies, like UHF, 700, 800MHz, then LMR-600 or 1/2" heliax would be recommended to get the most signal to your scanner. There is always something bigger and better, so you have to decide based on your budget.

As for connecting it to your scanner….
If you are using something like RG-58, you can connect directly to the radio using either an adapter, or get the cable custom built with the correct connectors to match the antenna and the radio.

If you are using something larger, like RG-8, LMR-400, LMR-600, heliax, etc. you really want to use a short flexible jumper to make the connection to the radio. These larger cables can be pretty stiff and can easily damage the radios connector. You can find short, pre-made sections of RG-54, LMR-200, etc. with connectors to match your radio.

Whatever you do, make sure you seal the antenna connection really well. You should also consider lightning protection and grounding to protect your radio and your home.

Antenna solutions

For base, I am using a discone from Radio Shack. It is not as 'sturdy' as other brands such as Diamond; but is electrically identical and works for me.

For mobile I use a magnetic mount. I have a couple and their performance are not all that different. The newer model claims a broad range from VHF low to 900 MHz UHF and above, is fairly short and works well. Either come with integral RG-58 coax that's plenty long enough for my situations. I like the mag mount solutions because I can remove them when I need to enter somewhere with a low clearance or don't want the obvious extra antenna showing.

Scanner Antenna and Window "Passthrough"

So Basically this is my setup. Really cheap and redneck. I had the antenna mounted on the actual ac unit scene in the picture but wasn't getting good reception (note: the ac was not running at the time.) I ended up putting on a box that I believe is the power on/off switch for the ac. I get better reception which is weird. I took to peices of wood and cut about 3/4 of an inch out of one, then screwed them together and put some wood glue and then some caulk in the middle to seal it. That peice of wood sits in the window sill and I run the cable through the little opening. It is stuff with tissues as insulation. To keep the window secure and from letting cold air in the the cracks I have some boards that sit flush against the crack and then two more to push it tight. I then have a window sill lock. The antenna I bought off of Amazon after finding it on a scanner website. It is a 34 1/8 inches tall stainless steal whip antenna with a magnet mount for mobile use but I use is as a base antenna. I have a radioshack pro-164 scanner. I have attached pics of everything. could you give me any recommendations. I am fine without picking up the chp freq real well, I am 16 and i dont have a job so money is a real issue. Currently I can't afford even a $20 antenna cause I need the money elsewhere as this is just a hobby. Anyway any recommendations.

continued

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It's ghetto fabulous ! The wood job that is...

OK, I understand the limited funds thing, been there, done that.

The antenna probably still too short for good low band coverage, but we can probably work around that.
Mag mount on the metal disconnect box is probably helping a bit since it will get you a bit of a ground.

I suspect the issue you are having is two-fold:
1. The antenna isn't up high enough. Altitude is key.
2. The stucco siding of the house is often put over a metal mesh lath. That is likely causing the majority of the issues. It will block the signal pretty effectively.

Here's what you can try:
Get the antenna up higher and away from the house. If you can get it up on a rain gutter, you might get some better performance.
If that doesn't work, you might need to make the antenna longer, but I suspect that isn't the core issue here. You could try adding another 10 inches or so of scrap copper wire, or even a metal coat hanger, to the top of the antenna.

Nice job on the improvisation. Getting the cable into the house can be a tough job. I've seen people do similar installs, and MFJ even sells a pre-made version.

better reception and mounting options

ok so i put the antenna horizontally magnet mounted on the gutter pipe about I guess 10ft up and the reception is a lot better. The next pic is showing the area where I could mount an antenna, in the future I would like to mount an antenna up there. Where could I mount one? How? Also would I need a ground plane, can you someone explain like for a base antenna, I would need a mount, and then a ground plane?? and how does the cable get connected to the antenna and could I do it myself, and how would I ground it or do I need to since it will be up on a two story house.

OK, glad that improved things.
Likely you are still losing some signal due to the horizontal polarization of the antenna. Getting it vertical and away from the walls (stucco/lath) would probably improve it a bit more.

As for mounting it, that's going to be tough.
Usually, you'd want it mounted to the house in some way. Look at TV antenna mounts, DirectTv mounts, etc. See what your neighbors have done for these, it can give you some ideas.

You could drop the magnetic mount antenna up there and it would probably work.

For extending the cable, you can purchase pre-terminated cables on line. Not sure what you have on the end right now.
Just order some extra cable with the correct connectors/adapter if needed.

My experience is that if you want to seriously monitor the CHP, you need a serious low band antenna. I built a 1/4 wave ground plane for 42Mhz. What a difference!

Antennas by Hustler, Radio Shack etc. say they cover 30-50Mhz - so does a coat hanger.

I'm using an Austin Spectra for a mobile and it can be tuned for low band via a cutting chart provided. It works quite well for a short loaded antenna. I can almost guarantee it would run rings around the Hustler. If you need to operate as you are, you might consider getting the Austin. NMO mount (no mount provided). It needs a ground plane to work well.

Colin,

Welcome to the hobby!! I also started young, with a 10-channel crystal scanner when I was in my mid-teens. It was a lot easier then...everyone was on VHF high band, and I barely used the ten channels...at first. That didn't last long...LOL

I applaud your ingenuity in your setup, and also understand being a teenager and financially strapped. Let me see if I can help you with your issue without costing you a bunch of money. Lets start with some technical background on our local CHP environment:

CHP Green is in use in the foothills from Sierra County north of Grass Valley to the Amador County line. They have several transmitter sites along the front range, and some of these sites are blocked from others by high terrain and distance. CHP dispatchers have each site identified on their radio console, and voting systems only send them the mobile audio that is on the strongest tower site, even if the mobile radio is hitting several. The dispatcher will then talk back to the officer on that particular site, assuming he/she is closest to it. For the Green, there are two 'repeat' sites that the mobile audio is transmitted back through: Banner Mountain in Nevada County, and Pine Hill NE of EDH where you are.

Seldom will you hear ALL the dispatch traffic on the Green, even on a dedicated low-band radio and antenna system such as I have in my work truck. When I am up in Nevada County, I hear all the mobiles loud and clear, but cannot hear dispatch talking to El Dorado County units, or at least they are very scratchy.

Because of your location, even if you get the optimal antenna setup, you will likely only be able to hear (well) the dispatch traffic on the local transmitter sites. Others will come in scratchy if at all, but you will hear the mobiles loud and clear if the repeat function is on. The reason you are hearing the Black so much better is your line of sight to one or more of the Black transmitter sites, which I think are also Pine Hill and the Resources Building in Sacramento (one of the tall downtown buildings). There are others but I can't recall where they are right now.

I concur with all the ideas that have been mentioned here, but to save yourself some $$, try this:

1. Find out how much more coax cable you need to reach from the end of the antenna cable to your window, with the antenna mounted on the nearest metal gutter or flashing at the top of your house where the mag mount will grip.

2. Once you have this hard number, you can get a price for, or network and try to find, an extension cable for your coax. You can try to get one with the correct connectors, but most extension cables I've used have standard PL-259 connectors on them unless custom ordered or custom built. You can get connector adapters to convert to almost anything for just a couple of dollars.

This setup won't be optimum, but it will improve your reception in the following ways:

- It will get the shaft of your antenna above the side wall of the house, where it will no longer be shielded by the metal under the stucco.

- It will add all that much-needed elevation to your antenna, so ALL your reception will dramatically improve. Even though it still won't be optimal for low-band, I would be willing to bet that it will be enough of an improvement that you will hear the dispatch and mobiles off Pine Hill, and probably the dispatch off the next 1- or 2-closest tower sites as well.

Getting your dedicated antenna system will still be your best bet, but I know it's frustrating to hear what you NEED to do when as a teenager you can't keep enough money around to put gas in your car or have spending money. There are a lot of Sac/Placer/El Dorado locals on this board who work in the Comms field, or are hams, and can probably help you make what you have work. Keep asking questions! Good luck.

David