Very good compared to what???
CHP Scanner Antenna?
- Thread starter Legal1313
- Start date
C40: Laird 40-47 MHz 0dB 1/4 Wave LowBand Base Loaded CB Antenna
The Laird C40, is a Lowband DC Ground base Coil Antenna for CB's operating in the 40-47 MHz range. This antenna is approximately 52.5 inches long with unity 0dB gain. The unit is 1/4 Wave and tunable.***This item is subject to an MOQ of 8 pcs***
www.arcantenna.com
That's a narrow band antenna that will not cover all the CHP freqs from 39 to 46MHz. This one will and without any tuning.C40: Laird 40-47 MHz 0dB 1/4 Wave LowBand Base Loaded CB Antenna
The Laird C40, is a Lowband DC Ground base Coil Antenna for CB's operating in the 40-47 MHz range. This antenna is approximately 52.5 inches long with unity 0dB gain. The unit is 1/4 Wave and tunable.***This item is subject to an MOQ of 8 pcs***
WPC39S0B-001 Wide Band Low Band 39-46MHz By Laird
WPC39S0B-001 - 2dBi Gain, 39-46 MHz, Hi-Speed, Hi-Cycle (10 Mins @ 100W) Mobile Antenna.
radio-accessories.com
I use a Thales 1600629, but that would flop around in the wind on the roof and would not last as long as that Laird 39-46 outdoors. Most of the time I use my Off Center Fed antenna and CHP blasts in even with the different polarization.
What about using a 9:1 balun and a bit of wire? Even if horizontal I would think it should work. Time to test.
What about using a 9:1 balun and a bit of wire? Even if horizontal I would think it should work. Time to test.
I recommend you read the thread from the start.
Many years ago when the local fire departments were on 46 MHz and without repeaters, my dad made a what I believe was a long wire dipole antenna that he mounted along the eves of the house. The scanner he was using was a BC100? ( First programmable handheld back in the 80's )
He could hear their handheld radios from miles away where my BC210 with an outside antenna would miss alot distant traffic.
If you have a good frequency tuned antenna, it will be better than a multiband antenna no matter how high you go with it.
HappilyRetired
Member
Thank you but as I've already written I am in an office building. The windows do not open.
As for an off center fed dipole, I've already been referred to the one that has 48 inches going up and 18 inches coming down and fed at the center point with a 300 ohm TV balun. 4:1. That suggests to me it is a VHF antenna. I've already been told as well that they do not perform well on low band. In order to get any kind of efficiency it would need to be at least 6 ft going up and I'm going to guess 2¾ feet 1/8 wave. That's a completely uneducated guess. But then I don't get the ability to receive VHF effectively and that is extremely important. My home is in Riverside County on the very tall hill overlooking Lake Elsinore and Canyon Lake where I have band specific antennas per radio. My altitude is roughly 1850 ft. My wife is ready to throw me out!
We have a lot of brush fires and where I'm at with all of the yellow grass being able to hear VHF is extremely important to me. Who's to know about 700/800? I'm told that 800 penetrates into buildings better but this is a cement building and the only window I have in my office faces the south. According to the database here the transmitters are all on the north side of the building except someplace called Box Springs. I can hear Riverside CHP just fine. But I'm not interested in Riverside. I can hear Riverside CDF with the whip antenna.
I appreciate the help. I really do. But this is starting to go into so many different directions that someone new to this like me that has little to no clue what some of you are even talking about. My amateur radio Elmer has me researching information rather than him just giving me the answers. So if I say something stupid it's because I don't know yet.
HappilyRetired
Member
No, my office is located in the center of San Bernardino. As I wrote I have no problem receiving at home because I have single band antennas for each radio. My home is in Riverside County where I have outdoor, single band antennas.
oldradioguy2010
Member
Here again, I cut some wire to approx. 58 inches soldered a 6ft. coax cable from the junk box. I can monitor CHP ( Ventura/Oxnard) to SLO and LA west valley .
Just a thought.
DW
So. Cal
Just a thought.
DW
So. Cal
HappilyRetired
Member
I don't know why the whip antenna that comes with a 996P2 and the BCD15x don't receive San Bernardino CHP well even though I am in a cement building. I would expect a signal would be strong enough since the database says they're transmitting with 120 watts. They also have multiple sites they transmit from including Strawberry Peak, which is right in front of me, Keller Peak that is slightly in front of me, and Box Springs which is right behind me. I've hiked the trails of Strawberry Peak from the bottom to the top, as well as Keller, so I'm familiar with them. It's my understanding that they're a simulcast system which causes me to be even more curious as to why I really can't hear them.
Okay. So I can't hear them. It looks like the solution is the Austin Spectra antenna, although somewhat expensive. They also have a pole with a NMO mount on it. I'd like to get the pole and see how they pop the mount on top of it because I think it's probably pretty simple. I can replicate it.
I'm planning on a Laird low band mobile antenna tuned for 42.5 MHz, which is midway between what I listen to. I'm told I can then use a Diamond MX3000 triplexer, which will let me split off the low band antenna and then use a multiband antenna on either another pole or a 36-in square piece of sheet metal tacked to the ceiling with the mag mount antenna facing down. I guess the triplexer will let me have up to three antennas but I think I only need two. Maybe I can use the center port and do a Laird VHF antenna tuned at 160 MHz to pick up Cal Fire and the Forest Service even better. I guess that I can use a 700/800 MHz mag mount antenna the same way. I am told that I can use a three-way cable TV splitter to feed each radio from the MX3000. Three antennas and an empty wallet later I should have pretty good reception from inside the building. I think.
I've got to say that I'm wondering if these radios are B stock and I have a problem with receive to begin with. Using the WX channels I can only pick up three and only one of them is solid. I got them off of eBay as new in the box. I've learned the hard way that you can't believe in eBay sellers.
The lower in frequency you go, the less it penetrates, and the more important it is to be outside. Any kind of metal reinforcement, especially if grounded, make it worse. As far as the site, at low band, 120 watts isn't that much, and it's probably just one or two folded dipoles, as opposed to higher gain antennas that might be used at higher freqs. The whip, being way shorter than 70" (42 MHz quarter-wave) and without a ground plane, is also pretty ineffective.
I think that's right for San Bernardino. AFAIK, 162.500 WXM66 is at Strawberry, 162.450 WWG21 is at Beeks Place (near Pleasants, between Santiago and Sierra), and you might hear 162.550 KWO37 Mt. Lukens or one of the 162.400 stations (Mt. Woodson KEC62 or Cactus City KIG78) or WZ2505 Bald Mtn. (up in the grapevine) on 162.425 in the right propagation conditions.
Interesting, I helped install the new KVCR TV transmitter on Box Springs, fired it up for the first time and built all the in building transmission lines for it.
HappilyRetired
Member
This online application go see location and frequency to be used. The second link is like here. Click on the call sign and it'll show you the actual measured coverage area of the weather channel. Click on the National Weather Service office and it will show you all frequencies assigned to it and their locations.
HappilyRetired
Member
Is it true that you can use the cable TV multicoupler to connect one antenna to multiple scanners? Or do you have to use an expensive s
Stridesberg?
Stridesberg?
Eng74
Member
It depends on how many scanners you are wanting to split the antenna between you will lose signal strength the more it is split. I would not split it between more than two scanners.
HappilyRetired
Member
If I understand decibel loss, there's a 3db loss for each connection. That means in theory I could use the two or three port catv splitter? I have three scanners that I want to feed. I'm told that cable TV is 75 ohm versus 50 ohm but for receive it really won't make any difference. The Stridsberg that I came across has an amplifier built in that makes up the 3db loss I guess. But damn that's just- the spending money on scanners is turning into an obsession.
Ubbe
Member
It seems that people have great success using $50 Electroline TV antenna amplifiers with several outputs. There are also ChannelMaster that have good products. Look for the noise figure NF that should be 3-4dB or less. If they don't state it then it's probably so bad that they don't want to announce it. If the outputs have max +6dB output level then its fine but any higher and you will need to attenuate the signal. If one output have a +10dB signal then you can connect a 1-4 splitter to it that then will reduce the signal by 7dB, or buy a set of different fixed attenuators. But the best solution are to use an adjustable attenuator that you can set to the optimum level for the actual receiver.
/Ubbe
Yes. But compare the specs --- pass band, any filtering, noise figure, .....
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