Post by bluebucketradio on Mar 20, 2016 6:43:28 GMT
Over on Part 15 dot us, i had mentioned CB radio a few times and have recently settled on a base station to use here at home.
The radio is Cobra 148 GTL 40 Channel AM/SSB Mobile on a Pyramid Power Supply, 100 feet of coaxial cable and of course up until a few days ago, i was using a dipole antenna with fair results. The Standing Wave Ratio across all 40 channels was 1.1:1 on channel 1 (26.965) and 1.2:1 on channel 40 (27.405) and it did pretty well for dx but wasn't great for local communications unless the other station was withing a few miles.
That dipole was used in the inverted V configuration and was not very high off the ground. Most dipoles do really well if you elevate them within a wave length of their intended band of operation. This one was not, in fact it was just mounted to the car port in the inverted V config. and was only 8 feet off the ground.
Just a few day's ago I decided to order a base antenna, now in the past i have had many antenna's for 11 meters CB, usually they were Antron 99, A Starduster, J-pole which was a pain in the butt to adjust for optimum performance and of course a home built Quad Beam. Out of all of those antenna's i mentioned, the home built 2 element quad beam was the best, now it didn't have the rejection (it did not null out stations behind the reflector) but it sure had a mouth on it and if no one was talking behind the beam I could zero in on stations that were too weak to hear on a vertical antenna.
Heck, i talked to Australia for nearly 30 minutes before a resistor popped in the radio due to over heating the rig.
Fast forward to the present, present. (both uses of the word here lol)
In 3 days will be my birthday, never mind how old i am, that's not important lol
My wife Stephanie asked what i wanted for my birthday and i settled on a new base antenna for my CB Radio here in the house.
What i ordered was the cheapest i could get by with on a limited budget and boy did it not disappoint me.
The antenna is a Tram 1499 no-ground plane antenna. I have included a picture, you can buy these things for $30 usd with no shipping cost from ebay.com
www.trambrowning.com/
So what are these short antenna's made of? Well, according to a few youtube videos of users taking these things apart to find out what they are made of, it is basically one big coil. A 36 inch coil with a fiberglass coating and what looks like a brass mounting plate with two mounting brackets.
The antenna company claims no SWR adjustments needed, which is mostly true IF your coaxial cable if 50 foot or longer and you are operating in the 11 meter CB band. However, with a balun made from coiling the coax a few turns or using an antenna tuner you can use it on the 10 meter band and it will handle up to 500 watts. I do not suggest running 500 watts into this antenna on either band, i just don't feel a short antenna like this could be safe running much more than 75 watts even in the 10 meter band.
Now, this antenna came via USPS and arrived earlier than expected which is great, i gathered up the things i needed to get this thing put on the air.
Grabbed the power supply, the Cobra 148 GTL and coaxial cable (100 feet) and of course the antenna. As soon as I had the antenna plugged into some cable and the radio i checked the SWR. Yeah, I was holding the antenna by the mounting plate in one hand and keying the microphone in the other hand.
Set the calibration on the radio's built in SWR meter and un-keyed the radio, switched to SWR and bam! 1.1:1 SWR on Channel 1, repeated the same steps on channel 20 and channel 40. SWR was the same on channel 20 1.1:1 and on channel 40 it was just a shade higher at 1.2:1.
So far so good, but will it transmit? I heard stations but can they hear me?
We live close to the Hal Rogers Parkway which gets a lot of traffic from Coal trucks and 18 Wheelers as well as travelers between Hazard and towns North of us.
I tried channel 19 the truckers channel and as soon as a couple drivers were done exchanging traffic (smokey reports) i asked for a radio check.
Radio is working, sounds good. Two stations, the two drivers that were talking said it works. WOW! Stephanie and I were blown away!
The antenna was inside the house, in my hand held above my head and someone on the other side of the mountain behind us in a mobile heard me, amazing little antenna!
Of course i wondered what it would do on a pole outside away from the 4 walls on our house so it was mounted to a pipe that is about 10 feet long and was mounted on the deck, the deck is roughly a foot and 4 inches off the ground. I did this as a temporary set up and plan on putting it up on the hill behind the house which should put it about 40 feet into the air above the house.
All in all, i like it. Well worth the money so far.
Of course it got me thinking too, what if i made an antenna that was mostly a coil for the broadcast band? I wonder if it would work? Maybe.
The thing about this antenna is the Coax balances the antenna system, so in essence the coax is part of the antenna making up for the shortness of the antenna itself. If adapted for 530 to 1700 khz , it would need to be ground mounted where i could take advantage of a ground radial system to make up for the really short antenna.
Just a theory, again man that antenna is cool.
10-4 - Maverick 390 E. Ky USA
