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  #1 (permalink)  
Old 04-20-2017, 7:19 PM
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Default Home Base antenna issues/set up Suggestions

I just purchased a Uniden 980ssb and with a little will for the car. Love the set up small compact and works well in the car. Swr 1.5 across the board right out of the box. I have a power supply in the house and are ready to use the uniden in the house. I have a metal roof on my town house, so I put the little will up on the roof the swr on channel 1 1.1 on channel 40 3.0 moved the antenna around for an hour till I found a sweet spot. 1.5 swr across the board, 2 hour later check the swr it's all over the place not even close. So after 2 day of this I'm looking for a good base antenna that I can mount a portable mast. The goal was to put a sirio 5000 mag mount on the roof. I live In an HOA and I need a setup that can be taken down after every use. I was think about using a pool pole as a mast with an umbrella stand as a base. I've looked in to A99s the problem is they are huge I do like the sirio boomerang looks like it might be up my alley. I don't have time for DYI I have 2 year old and have no spare time for projects even thought I love them. Please any idea on antennas would be great I would love to make it to dx land with the ssb. Thanks
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Old 04-20-2017, 11:48 PM
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I don't know if it will suit your needs, but a 1/4 wave (102") whip will work very well on your metal roof. Back in the dark ages of the '70s and '80s when I fooled with CB I had one of these up about 30' on a barn roof and I was endlessly accused of running power, but I never had a PA, just what came out of the back of the radio. I talked around the country and to several other countries on 15W PEP.

These whips are fairly unobtrusive, but if you're worried about it you could say that it's a lightning rod, I suppose...don't really see how the HOA could object to that.
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Old 04-21-2017, 4:12 PM
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Originally Posted by DJ11DLN View Post
I don't know if it will suit your needs, but a 1/4 wave (102") whip will work very well on your metal roof. Back in the dark ages of the '70s and '80s when I fooled with CB I had one of these up about 30' on a barn roof and I was endlessly accused of running power, but I never had a PA, just what came out of the back of the radio. I talked around the country and to several other countries on 15W PEP.

These whips are fairly unobtrusive, but if you're worried about it you could say that it's a lightning rod, I suppose...don't really see how the HOA could object to that.
Good idea! And that 9 foot whip can easily be made into a CB ground plane, by adding just a few radials!!
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Old 04-21-2017, 4:30 PM
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Good idea! And that 9 foot whip can easily be made into a CB ground plane, by adding just a few radials!!
The metal roof would be his ground plane, no radials needed. Even a relatively small roof would work far better than radials, so long as it was at least 9' in all directions from the antenna.
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Old 04-22-2017, 1:03 PM
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The metal roof would be his ground plane, no radials needed. Even a relatively small roof would work far better than radials, so long as it was at least 9' in all directions from the antenna.
True, but radials would be needed if he decided to mount the antenna up higher (like 20 or 30 feet) on a mast!
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Old 04-22-2017, 1:31 PM
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True, but radials would be needed if he decided to mount the antenna up higher (like 20 or 30 feet) on a mast!
Correct if he uses a mast. He was talking about something he could take down when not in use to avoid friction with his HOA. I was suggesting something that might be able to be up all the time. I think I would find having to put up & take down an antenna that way to be a monumental PITA.

Mine stayed on that barn roof till the barn got new metal, and was noticed by only a handful of people as not being just another lightning rod in all the years it was up. I rescued it from the scrap pile and it's hung up in the same barn. Not likely to get back into CB at this stage of the game, but one never knows. If I do, I'll have to hire somebody...no way I am shinnying up on that 12/12 pitch roof at my age!

OP, sorry if this has gotten far afield. I hope someone makes a suggestion that you can adapt to your use.
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Old 04-22-2017, 1:46 PM
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You can buy a 10m PAR 1/2 wave end fed antenna or make one for a few $ and they work really well vertical. It would have the same performance of an A99 but instead of a fixed fiberglass stick its just 18ft of wire with a small box at the base. You can put it up temporarily using a 20 to 33ft telescoping fiberglass mast and when your done the mast will collapse down to 3 or 4ft depending on the model.

I've made many of these and they kick butt over most any home made antennas you can come up with. I can give you plans on how to make one that will handle 100w or even a 1kW version and the 100w one only cost a few $$ to make.
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Old 04-22-2017, 6:55 PM
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A couple of people have asked me for the end fed antenna plans, so here are a couple of links I used when making them. The wide band 64:1 transformer can cover about 3 through 30MHz depending on the ferrite core type, size and number of cores used.

You attach a wire 1/2 wavelength long and the transformer matches it very well to 50 ohms, and it will also cover many harmonically related bands higher in frequency than what you cut the 1/2 wavelength of wire for. Most of the ones I make have about 63ft of wire to cover the 40, 20, 15 and 10m bands, all without a tuner. I have used the same transformers with about 16ft of wire to just cover the 10m amateur band and a little more wire around 18ft will cover the CB band. There is not much difference between this antenna and say an A99 in that you are exciting an 1/2 wavelength radiator with a matching network to 50 ohms. The difference is an A99 has a very narrow band matching circuit only designed for the CB band and this end fed transformer is very broad band.

Its recommended to have a good common mode RF choke in the coax not too far from the transformer to eliminate any RF on the feedline, and in my experience there is no detectable RF on the feedline unless you operate the antenna outside its resonant range.

Here are three links I refer to when making the transformers:
https://forums.hamisland.net/showthr...-with-a-twist?
PD7MAA HOMEPAGE: Multiband end fed antennas 3.5 - 30mHz
https://pa3hho.wordpress.com/end-fed...d-fed-english/

For up to 100w SSB or maybe 30w key down AM I use an FT-114A-43 ferrite core. For up to 400w SSB or about 100w carrier I use a single FT-240-43 core. The 100w version is nice because it will fit in a plastic box a little bigger than a Zippo lighter. I've made some versions that handle about 1kW but on lower frequencies than CB and I would have to experiment to see what core is best for that much power on CB/10m. I suspect a pair of FT-240-61 cores would be a starting point if you need high power.

You will notice the common theme in the three links where they wind the transformer with 2 turns of a twisted pair for the transformer primary, then 14 turns for the secondary and they cross over the core and reverse the windings on the secondary after 7 turns. You have to study the pictures in the links very carefully to note how the crossover is done, otherwise it doesn't work.

The FT-114A-43 core is about $2 and the FT-240-43 core is about $9. For a version that will easily handle a stock CB or up to about 100w SSB, by the time you buy the core, a small plastic box and some wire and a chassis connector, you might have $10 in the antenna. And it will perform as good if not better than any 1/2 wave base antenna out there.

For a really good common mode choke for the CB band, get an FT-240-61 ferrite core and wrap 8 turns of RG-58, RG-8X or better yet, RG-142 coax through the core. Its probably best to do 4 turns then cross over and reverse like the transformer is wound, but just wrapping 8 turns through it will make a fantastic choke targeted for the CB band. You can simply use the coax running to the end fed antenna and wrap it so the choke is 5 or 10ft down the coax from the end fed transformer.

Once you have the transformer and end fed antenna working and if you decide to get an amateur license, the same transformer will work 40 through 10m depending on how much wire you use. For CB use you generally want to hang the antenna vertical and a tree will work or a telescoping fiberglass mast makes setup and take down easy. For skip on CB or for the lower amateur bands I use them horizontal about 15 to 30ft off the ground depending on whats available to hold them up.

Now you have some plans, so go make an antenna.
prcguy


Edit: For the transformer wire you can use enameled transformer wire or you can use Teflon insulated (its a pia because it wants to unwind) or for low power like stock CB a strand of wire from CAT5 Ethernet cable is great because its insulation has good RF properties. When winding the transformer its best to make the first wind, then push the next winding through with your finger with wire near the last winding then pull the remainder of the wire through the hole rather than sticking the end of the wire through the hole and pulling the rest through. This makes the windings tighter against the core.

Last edited by prcguy; 04-22-2017 at 7:48 PM..
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Old 04-23-2017, 6:37 PM
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Thanks for the links prcguy.....
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Old 04-23-2017, 7:49 PM
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No problem and I hope to see pics of some finished antennas.

Update: For a 400w SSB size transformer for mostly CB/10m use it will be better to use an FT-240-61 core over the #41 mix I mentioned earlier. I'm still investigating an 800w version and not sure if it would use two FT-240-61 cores or two FT-240-52 cores. But does anyone really need an 800w vertical for CB?
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Thanks for the links prcguy.....
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