Terminated folded dipole question

[KD8JUF]

Hello Everyone,

I'm a new general setting up his shack for the first time. I have a Kenwood 570 D/G and am now working on an antenna. I saw where B-Square has a Terminated folded dipole for 10M-160M (122 feet long) and a 10M-80M (66 feet long). Has anybody dealt with this company before? DO you think this would be a good starter antenna? I'm located in the burbs of Cleveland Ohio.

Thanks for your advise and comments!!!


Mike
KD8JUF

 

[bioman]

DO NOT BUY A WIRE ANTENNA!!!!

ALL hams should be able to "roll their own " wire antennas!!!

i can understand purchasing baluns etc but Marconi spins in his grave every time a ham BUYS a wire antenna

 

[Robb]

I recently purchased the Alpha Delta DX-CC 10-80m fan dipole. This choice was recommended to me by Moleculo. If available space is a problem; this is a solution. Materials used by Alpha Delta are top notch - too.

 

[Beetle]

A "terminated folded dipole" is a really poor antenna for general use. The "termination" is a large resistor combination, providing around 50 ohms of non-reactive impedance across the whole spectrum. Most of your RF does nothing but heat up that resistor. Some of it WILL radiate, and you WILL probably be able to make some contacts, and you probably WON'T have to use a matching network (it's 50 ohms non-reactive everywhere).

I'd build a single band dipole, say for 40 meters, and get it set up. See how it works. Then if you want 80M, build another one. A single band dipole can be directly fed with 50 or 75 ohm coax very easily, with no matching network required.

The military uses TFD antennas because they have to be "frequency agile" - able to jump from one frequency to another, using only one antenna. They're generally within reasonable range of the other stations, so the fact that 90+% of the transmitter power is wasted heating that terminating resistor is not of primary concern for them.

 

[W5LZ]

I don't know anything about that company other than whay you've said here, so can't comment on them.
I can say that this TFD may be a good "starter antenna" in that you can't help but improve on it. Almost any antenna will be an improvement, in other words. The only benefit I can see with either of the two antennas is that they are fairly short so don't require the 'normal' space to mount them (basically a center fed 1/4 wave for the advertised band). While they will 'load', and require less than normal space, you never get something for nothing, and you will give up in performance. That type of antenna isn't much good for anything dealing with efficiency. I think you could make a better choice. This company isn't the only one making this type of antenna. There's a very 'big name' company that's made two 'versions' of this sort of antenna for a long time, at a ridiculous price. They are just as 'worthless' except in very specific situations.
How much space to you have to put up an antenna? Keep in mind that a dipole doesn't have to be perfectly 'straight', it can be bent into a lot of shapes and still produce a reasonable signal.
- 'Doc

 

[bioman]

why not tell us a little about your potential installation and what you would like to do with an antenna and we can try to make some suggestions.......

i hate to see hams spend 100+ dollars on $10 worth of wire and some insulators that they could have made from $5 worth of PVC pipe

if you have 122' to run the one antenna you mentioned why not just throw up a 75M dipole....feed it with ladder line and work everywhere with it?

if you dont have a connection for ladder line on your tuner you can run the ladder right to your shack window put a 1:1 current balun there and then run coax inside the house to your radio

TA-DA! all-band antenna that will do you some SERIOUS justice and you can feel the pride of "HEY! I BUILT THIS!" not to mention save yourself some coin in the process

 

[wavrider]

Well Said.


All hams, should roll their own antennas. especially wires. Certain items can be purchased and are available, Baluns insulators etc.etc, Those can be home grewed also, 1:1, 4:1 baluns can be wrapped on air core (pvc) insulators and used.

Roll your own, experiment, and have fun.

DO NOT BUY A WIRE ANTENNA!!!!

ALL hams should be able to "roll their own " wire antennas!!!

i can understand purchasing baluns etc but Marconi spins in his grave every time a ham BUYS a wire antenna

 

[n5xes]

theirs' is a knockoff clone of the B&W folded dipole/flattop style terminated antenna. we have been using this design for over 50 yrs. in the USAF.

 

[WB4TJH]

Bad antenna?....nonsense. B Square Engineering took the original 90 foot design and RE-designed it to make it optimum on the amateur, not military bands and extended it to be resonant on 80 meters at 122 feet. I have the 122 foot model up as an inverted V at about 40 feet at the apex, and signal comparisons with a 130 foot dipole fed with balanced feedline don't show enough difference to even make note of, both on receive and transmit. Yes, I agree that the old B&W 90 footer is not a great antenna on the ham bands--it was designed for the military bands and there does a fine job. But that is a 60 year old design. So take a hard look at the NEW DESIGN being offered by B Square that is designed for the amateur bands.

 

[Mudfoot]

Bad antenna?....nonsense. B Square Engineering took the original 90 foot design and RE-designed it to make it optimum on the amateur, not military bands and extended it to be resonant on 80 meters at 122 feet. I have the 122 foot model up as an inverted V at about 40 feet at the apex, and signal comparisons with a 130 foot dipole fed with balanced feedline don't show enough difference to even make note of, both on receive and transmit. Yes, I agree that the old B&W 90 footer is not a great antenna on the ham bands--it was designed for the military bands and there does a fine job. But that is a 60 year old design. So take a hard look at the NEW DESIGN being offered by B Square that is designed for the amateur bands.

They are fine for what they are. If your lot allows, there are tons of better more efficient options. We used them extensively in the military. Easy to deploy and broadbanded. Great for NVIS operations.

 

[2RT307]

why not tell us a little about your potential installation and what you would like to do with an antenna and we can try to make some suggestions.......

i hate to see hams spend 100+ dollars on $10 worth of wire and some insulators that they could have made from $5 worth of PVC pipe

if you have 122' to run the one antenna you mentioned why not just throw up a 75M dipole....feed it with ladder line and work everywhere with it?

if you dont have a connection for ladder line on your tuner you can run the ladder right to your shack window put a 1:1 current balun there and then run coax inside the house to your radio

TA-DA! all-band antenna that will do you some SERIOUS justice and you can feel the pride of "HEY! I BUILT THIS!" not to mention save yourself some coin in the process

If I had the space, that's exactly what I would do.

73,
Brett