CB Radio - home base question

[HelloWalls]

Hello ladies and gentlemen,

I recently came to have a Cobra 25 LTD Classic CB radio, and I have power for it within my home. I have purchased a Maco 5/8 Wave Antenna and will be assembling and mounting this to an exterior wall. I was wondering, as I am a newbie with CB radio and bought the antenna after a few too many; how do I connect my CB radio to this antenna? I assume utilizing coax cable, but I was wondering if someone who knows more than I could shed some light on thjis for me. Thnx

H.W.

 

[UrbanHunter]

That would typically require RG58 coax cable with UHF PL259 Male connectors at both ends. There is a large connector on the back of your base station and an identical one on your antenna. When ordering the cable you need to order one that is long enough to be routed from your base station to the antenna fitting without having too much slack, but definitely not too short. Be sure to order cable the the PL259 Male connectors, there are BNC connectors but they won't work for your application.

 

[HelloWalls]

That would typically require RG58 coax cable with UHF PL259 Male connectors at both ends. There is a large connector on the back of your base station and an identical one on your antenna. When ordering the cable you need to order one that is long enough to be routed from your base station to the antenna fitting without having too much slack, but definitely not too short. Be sure to order cable the the PL259 Male connectors, there are BNC connectors but they won't work for your application.

So the issue I'm running into is (mind you it is not fully assembled yet) but my antenna doesn't seem to have a female portion for that cable ending

 

[Biggkidd]

So the issue I'm running into is (mind you it is not fully assembled yet) but my antenna doesn't seem to have a female portion for that cable ending

Pictures would help all...

Also do a little research antennas work better or worse at certain heights above the ground. Since you're likely mounting to wood do you require a ground plane? Some antennas do some don't. Higher is generally better within the understanding of wavelengths.

 

[Bacpacker]

Rg 58 will work at that frequency range. But I'd go with something like RG 8. It has much lower losses unless you coax run will 25' or less

 

[Haertig]

I have purchased a Maco 5/8 Wave Antenna

That is quite the antenna for that little 4 watt mobile radio. Your antenna is rated at 1200 watts. You'll certainly be within spec on that one.

Both the antenna, and the radio, say they have SO-239 connectors. So you need a length of coax with a PL-259 connector on each end (which is typical). PL-259 is the connector that mates with the SO-239 connector.

The coax you need between these connectors is 50 ohm, not to be confused with the 75 ohm coax that you might see connected to a television cable input. Better cable is less lossy, thicker, stiffer, harder to work with and more expensive. So it's a trade off. The longer the cable run needs to be, the better the cable you should use. The less loss the better. Additionally, the power handling capability of the coax is of no concern to you given a 4 watt radio.

I am a newbie with CB radio and bought the antenna after a few too many

I kindof, maybe, almost, thought that a little. Don't forget about grounding and lightning protection. I'm no expert on that. But do read up on it. That's a pretty tall antenna you're got there (20 feet). It would be good to disconnect the coax cable from the back of your radio when a thunderstorm is approaching. Also, you want to waterproof the connectors that are outside. Water ingress is the number one killer of coax, and you're probably going to be shocked at how much this coax can cost. It's not going to be one of those $7 things you can buy at Amazon or Best Buy. 25 feet of connectorized RG8X is probably going to be around $40. The good thing is that CB radio is at low frequencies (HF) compared to mobile ham radios (which are typically VHF and/or UHF). And the lower the frequency, the lower the loss in the cable. So you shouldn't need extremely-low-loss cable for the frequencies you'll be working at, compared to what you would need for, say, HAM UHF frequencies if your cable run is long. In English (if you can call this English!) this means that you can probably get by with RG58 or RG8X instead of the much more expensive RG8. But if you're only at 25 feet, pretty much anything you'll be able to find with PL-259 connectors on it will work fine at CB frequencies (this is only my opinion, of course!)

Good luck! Be sure and report back on how your new setup works.

 

[Bacpacker]

RG8X is what I intended to post

 

[UrbanHunter]

I looked at the online manual for that antenna, the fitting is on a metal plate and has a wire soldered to it that goes to the antenna assembly by a bolt bracket shown on Page 5, Detail A1 of the manual. https://cdn.shopify.com/s/files/1/0661/9627/files/MACO_V58.pdf?8007894688789295621

 

[zoomzoom]

I recently came to have a Cobra 25 LTD Classic CB radio, and I have power for it within my home.

That is a 12V DC radio, right? What are you using to power it?

 

[Faez]

An SWR meter is necessary to get a match so you don't have a transmitter power loss from standing waves that reflect power back.

Where you mount that Maco 5/8 wave is critical for top performance and while it has its own ground plane, height from the earth can make a difference. Since CB is 11 meters, I would suggest at least a 1/2 wave high which is 5.5 meters.

If you get the Maco installed and matched right, it has a 5 DB gain is makes a difference with 5 watts output. That antenna is made for 1200 watts out for 11 meters, which is illegal, but I don't think the FCC cares anymore. Most likely neighbors would complain if you run high power on AM. Another tip is to have a good earth ground system hooked to the CB transceiver. It helps keep the coax shield from radiating.

As already stated, RG8X is the best and I suggest Belden with Amphenol PL-259 connectors for the best possible outcome.

 

[Haertig]

Just FYI for newbies, when talking radio power - 5 watts, 1200 watts, whatever - remember that this is transmit power. It won't help you receive any better. So while a mega amplifier might blast your transmissions all the way to Pluto, you won't be able to hear any more replies than you would have with a less powerful transmitter. The Plutonians may be able to hear you, and they are all responding "Hey, we hear you just fine. Please turn down the power a bit!", you won't hear their reply and will keep screaming away at the top of your lungs.

The antenna is where your money should go first, not transmit power. Not that this thread was about transmit power (other than my previous offhand comment that the antenna mentioned will handle a ton of it!)

Just FYI.

 

[Bacpacker]

Antenna and coax. Totally agree

 

[Biggkidd]

A lot of amps also have a built in DB gain for the receive side too. Two or three of mine do and it's quite the difference when it's on versus off! My radios have enough power I often run just the receive gain on the linear and do not need to boost the transmit power.

But yes a good / great antenna is money well spent and the first place to make the best that you can afford. Then boost the radio and or add a linear (amp)

 

[Haertig]

A lot of amps also have a built in DB gain for the receive side too.

I did not realize this. Thanks for pointing this out!

 

[Faez]

Just FYI for newbies, when talking radio power - 5 watts, 1200 watts, whatever - remember that this is transmit power. It won't help you receive any better. So while a mega amplifier might blast your transmissions all the way to Pluto, you won't be able to hear any more replies than you would have with a less powerful transmitter. The Plutonians may be able to hear you, and they are all responding "Hey, we hear you just fine. Please turn down the power a bit!", you won't hear their reply and will keep screaming away at the top of your lungs.

The antenna is where your money should go first, not transmit power. Not that this thread was about transmit power (other than my previous offhand comment that the antenna mentioned will handle a ton of it!)

Just FYI.

Very important point and also makes it more important to adjust your antenna to resonance. The thing about the antenna mentioned is its having a 5 db gain, if adjusted to resonance, will be appreciated more on the receiving end than the transmitting.

My advice if shopping for a transceiver, CB or Ham, AM, FM, or SSB, is to buy one with the best receiver and put up the best antenna you can for your space.

The setup mentioned in the OP should work well with a good antenna installation. I would suggest the poster search online for info on installing that particular antenna. Lots of good tips from users.

 

[Swing]

I have not read all this, but has anyone suggested a matchbox to match the radio transceiver to the antenna? In the past my Dad, Hubby and I have used a Johnson KW matchbox for all types of antennas to match the different frequencies. This is for ham radio, various HF bands. And on such as a 100 ft, sky needle to a 32 guage copper wire over a 6th floor balcony to trees across the street.

Best wishes with your antenna.

 

[Faez]

I have not read all this, but has anyone suggested a matchbox to match the radio transceiver to the antenna? In the past my Dad, Hubby and I have used a Johnson KW matchbox for all types of antennas to match the different frequencies. This is for ham radio, various HF bands. And on such as a 100 ft, sky needle to a 32 guage copper wire over a 6th floor balcony to trees across the street.

Best wishes with your antenna.

That sounds like a great antenna, especially for receiving. I have had both the 275 watt and the 1 KW Johnson tuners in the past. Great tuners with fixed link coupling that I preferred over any PI network tuner. When I converted my station to all homebrew I designed and built, I used a homemade tuner with a swinging link. I could match almost anything to any of the homebrew transmitters. I sold off all of it by the early 2000s.

Since the OP is about using a Marco 11 meter antenna, fed with 52 ohm coax, a matchbox would just be an unnecessary lossy circuit. That kind of antenna tuner was designed for 300-600 open line or twin lead that actually works as part of the antenna for 10-80 meters.

The important factor to feeding an antenna with 52 ohm coax is to get a 1:1 match where the coax attaches to the antenna. The kind of antenna as mentioned here, has a driven element made to adjust to match the coax at that point. Using a tuner between the transmitter and the coax, is unnecessary for CB since the frequencies to be covered are all 11 meters. All a tuner does between the XMTR and coax, is keep down the SWR so not to burn out the final transistors or tubes for off resonance use. Lots of power lost in tuners used this way.

Also the OP mentioned mounting on an outside wall. I would recommend getting it above the roof peak.