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Slim Jim or J-pole antenna?
- Thread starter masel
- Start date
As W5LZ stated... I think a slim jim was named that because of the materials used. I have a dual band 2M/440 Slim Jim from Slim Jim Info, and it's made of ladder line.
Most of the J Poles I've seen are made of copper pipe or aluminum tubing Blackbird VHF/UHF JPOLE Base Antenna 2M/70CM - Main Trading Company
BTW, the N9TAX is great for travelling. It has very solid construction, gets tossed in my suitcase, and keeps me entertained while I'm stuck in a hotel in who-knows-where.
73,
RT307
Most of the J Poles I've seen are made of copper pipe or aluminum tubing Blackbird VHF/UHF JPOLE Base Antenna 2M/70CM - Main Trading Company
BTW, the N9TAX is great for travelling. It has very solid construction, gets tossed in my suitcase, and keeps me entertained while I'm stuck in a hotel in who-knows-where.
73,
RT307
As already said a Slim Jim is a J-Pole antenna but made from ladder line rather than from copper pipe.
I took a look at that 'Blackbird' antenna and except for the long element having a 'take-down' connector in the middle of it, it appears to be the same antenna as was made by 'Arrow'. And since 'Arrow' company isn't around anymore (sold it) I'd bet it's from the buyer of the 'Arrow' company. That particular construction scheme has been copied a lot. And I have to think that's because they are simple, and do work well. They aren't the greatest things since sliced bread, but they certainly do as well as any other 'J'-pole.
I also wouldn't get to 'influenced' by TOA, that's hugely variable just from how and where the thing is mounted. They do work and that's the biggy.
- 'Doc
I also wouldn't get to 'influenced' by TOA, that's hugely variable just from how and where the thing is mounted. They do work and that's the biggy.
- 'Doc
The antenna zeppelin ( j-pole now ) was invented a century ago.
The balloon gunners used to telegraph enemy data.<can not stand it>
"Radios" were motor generators without valves.^^ ab v c^^
http://en.wikipedia.org/wiki/J-pole_antenna
The slim-jim antenna has a higher resistance of irradiation, and can give better performance for it.
Also the angle of irradiation is lower in the slim-jim,
by the capacitance added by the curve of the folded radiating top hat.
nocpc.
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I'm sorry, but that makes no sense because there is no top hat to a 'J'-pole. The transmitters used with those old 'zepp' antennas didn't have a 50 ohm impedance, which is the 'norm' for most modern transmitter. A 'J'-pole is not a typical 'zepp' antenna, but it is similar. There's a lot 'un-said' in that...
- 'Doc
- 'Doc
the load impedance has nothing to do with the antenna.
An Zepellin antenna can be loaded 10-20-30-40-50-75-100-500-6000 ohms
I'm going to invent a new name for each load??
A typical Zeppelin or Zepp antenna has a characteristic impedance of hundreds of ohms. It is not "loaded" at 10 or 20 or 50 ohms or whatever. You can use a matching network to present a 50 ohm load to the transmitter but the antenna is still hundreds of ohms....or more.
"If to this antenna it it is installed vertically with the radiant up the name of antenna J which is a Zeppelin antenna takes a form similar to the letter "J", and here."
LU6WG Radio Club Puerto Madryn
:tongue:
Doc, their website shows copywrite 2013:
Arrow Antennas Portable Satellite Yagi Jpole 2m 6m
I cannot remember if the Blackbird was solid aluminum as the Arrow advertises to be.
73,
RT307
I honestly can't say, but I'm assuming that they are at least approximately the same antenna. Solid or hollow elements? Beats me. Never had my hands on a 'Blackbird' but do own an 'Arrow'. Just going by pictures, I can't tell them apart.
- 'Doc
- 'Doc