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Author Topic: Quick disconnect for balanced feedline  (Read 656 times)
K1CJS
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Posts: 5863




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« on: April 22, 2005, 09:00:46 AM »

N4ZOU's suggestion:

".....buy a plastic electrical box suitable for use with a 115 VAC wall outlet.....buy a matching 115 VAC socket.....Your 300-ohm feed line to the antenna connects to the terminals and feeds through a hole you drill in the back. Do not use the ground terminal! Now look around at there selection of 115 VAC plugs. Find one that would be easy to connect to the feed line running to your tuner. ....."

I'm sorry but this is NOT a good idea--unless you like to live dangerously.  I definitely wouldn't trying this at all.

The one reason this isn't a good idea is this one:  If you're in a hurry or distracted, how easy is it to plug your tuner input line to a 115 volt outlet?  You may say because the shell isn't there it won't happen--but the 115 volt plugs and sockets are for 115 volt connections.  Using them for anything else is inviting trouble and disaster to happen.

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KC3PJ
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Posts: 47




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« Reply #1 on: April 21, 2005, 02:57:05 PM »

Anyone have ideas for a inline quick disconnect for 300 ohm feedline? It will be out of the weather. Just getting tired of disconnecting at the back of the tuner every time I hear thunder. Thanks.
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K5LXP
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« Reply #2 on: April 21, 2005, 03:02:00 PM »

Banana plugs/jacks.  I've heard of some guys using Powerpoles.

Mark K5LXP
Albuquerque, NM
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W4TME
Member

Posts: 299




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« Reply #3 on: April 21, 2005, 03:54:39 PM »

In addition to using something like a knife switch (DPDT)for the disconnect, also use a surge suppressor for balanced lines to protest from lightning.  You are not always home when storms brew up.

http://www.arraysolutions.com/Products/ice/impulse1.html#2

-Tim
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W4TME
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Posts: 299




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« Reply #4 on: April 21, 2005, 03:57:35 PM »

Whoops! I didn't mean to say "protest from lightning" It should read "protect from lightning". :-P

-Tim
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WB6BYU
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Posts: 13017




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« Reply #5 on: April 21, 2005, 04:43:35 PM »

The binding posts on most tuners will take banana plugs
in the center hole - that is how they are designed.

Though mounting a DPDT knife switch in a convenient spot
to ground the incoming feeders isn't a bad idea either.
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N6AJR
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Posts: 9888




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« Reply #6 on: April 21, 2005, 04:57:41 PM »

I hve seen used  some through the wall female to female pl259 connectors. ( 2 inch or 4 inch and even 6 inch.) Buxcommco.com has them.  

you drill a couple holes through the wall and mount these. the center will take a banana plug so space them to match your feedline and run them through to pass through the wall.

mount a second set direct to ground and when needed unplug here and plug in there.

also good for making mounts for pl259 antennas on pick up rails etc.
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K0ZN
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Posts: 1531




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« Reply #7 on: April 21, 2005, 06:15:39 PM »


Hi.

I have been using automotive type "spade" quick connects on two antennas fed with 450 ladderline for a couple of years. They seem to work just fine and make a good low resistance contact. Just be sure to solder them to assure good contact. I put a little silicone sealant on the soldered part to minimize corrosion.

We have a lot of severe thunderstorms and intense lightning around here in the spring and summer (eastern Kansas) and I like to TOTALLY disconnect the antennas outdoors and ground the antennas well away from the house and/or feedlines coming in the house and the spade connectors seem to be a good answer. They are not "locking" but have a pretty fair amount of resistance to coming apart. I have had no problem with the wind pulling them loose in the middle of a span of about 10 ft. between anchor points.

As an alternative, I suppose you could use the small COPPER PLATED alligator clips too. You probably would want to slip a short piece of poly tubing over them to prevent them from shorting together if your line is subject to much movement from the wind.

You said you were using 300 ohm line. Unless you have an unusual situation, 450 ohm ladderline is better in every category (electrically and mechanically) except cost, and it is not really "expensive" stuff. ...just some food for thought.

73,  K0ZN
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WA6BFH
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« Reply #8 on: April 21, 2005, 08:35:49 PM »

A diagonal cutter!
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K8ZO
Member

Posts: 175




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« Reply #9 on: April 21, 2005, 09:35:33 PM »

RS used to sell a 300 ohm line splice/connector.   Probalby do not anymore, but somebody must or has some.

K8ZO
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N4ZOU
Member

Posts: 340




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« Reply #10 on: April 22, 2005, 07:27:22 AM »

Go to your local building supply or hardware store and buy a plastic electrical box suitable for use with a 115 VAC wall outlet. Also buy a matching 115 VAC socket to mount in it. Your 300-ohm feed line to the antenna connects to the terminals and feeds through a hole you drill in the back. Do not use the ground terminal! Now look around at there selection of 115 VAC plugs. Find one that would be easy to connect to the feed line running to your tuner. This plug should not have the third ground plug or you should be able to remove it. You also will not need the clamping and cover side of the plug so discard that part or put it in a box if you think you might need it later. Look at the socket between the terminals and you will find that there are small strips connecting them in parallel. You can break these connecting strips to isolate the two sockets from each other. If you like you could install a second antenna and feed line and use your two sockets and single plug to select between them by simply plugging in the plug to the desired antenna.
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K1CJS
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Posts: 5863




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« Reply #11 on: April 22, 2005, 09:01:39 AM »

The ugly posting out of sequence bug rears its ugly head yet again.....
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K1CJS
Member

Posts: 5863




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« Reply #12 on: April 22, 2005, 09:02:23 AM »

N4ZOU's suggestion:

".....buy a plastic electrical box suitable for use with a 115 VAC wall outlet.....buy a matching 115 VAC socket.....Your 300-ohm feed line to the antenna connects to the terminals and feeds through a hole you drill in the back. Do not use the ground terminal! Now look around at there selection of 115 VAC plugs. Find one that would be easy to connect to the feed line running to your tuner. ....."

I'm sorry but this is NOT a good idea--unless you like to live dangerously.  I definitely wouldn't trying this at all.

The one reason this isn't a good idea is this one:  If you're in a hurry or distracted, how easy is it to plug your tuner input line to a 115 volt outlet?  You may say because the shell isn't there it won't happen--but the 115 volt plugs and sockets are for 115 volt connections.  Using them for anything else is inviting trouble and disaster to happen.

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W1GFH
Member

Posts: 23




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« Reply #13 on: April 22, 2005, 11:09:32 AM »

1. Never use high voltage AC plugs and sockets for anything but high voltage AC. The risk of confusion is too great to chance.

2. Banana plugs and jackplates are commonly used for connecting 300 and 450 ohm feedlines.
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X-WB1AUW
Member

Posts: 559




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« Reply #14 on: April 22, 2005, 08:00:21 PM »

First ham shack I ever visited had a knife switch, and 450 ohm ladder line.

When an antenna wasn't in use, it was gounded.

73
Bob
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