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Author Topic: Indoor Antenna for Shortwave RX?  (Read 2098 times)
AD0AE
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Posts: 78




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« on: August 15, 2013, 08:47:38 PM »

So once again, another antenna question by AD0AE...

I have been wanting to do some monitoring of CW and just general  shortwave listening with the IC718 I have.  When I was a kid, my dad had an older, analog, shortwave receiver.  I always amazed how you could just put the whip antenna up and hear quite a bit of activity on any given night.

Anyway, I have been wondering about possibly attaching some sort of whip directly to the backend of the IC718.  Maybe use an old 2-m whip antenna I have as a very quick and dirty indoor whip antenna for basic shortwave monitoring. 

Are there any other recommendations?  Maybe a multiturn loop antenna?  Maybe a wire?  The whip is appealing because it will also keep the XYL happy, whereas string wires across the room may not...

Thanks
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VA7CPC
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Posts: 2372




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« Reply #1 on: August 15, 2013, 10:20:02 PM »

FWIW --

A whip on the "hot" center wire of the antenna socket, and a wire trailing on the floor on the "cold" side (the threaded part) (or maybe just attached to a "ground" screw on the IC-718) ought to work.

The general rule for these things:

. . . Keep adding wire until you can hear what you want to hear, or until you become limited by local RF interference.

You should understand that RF levels, inside a house, can be quite high.  Small power supplies -- cell-phone chargers, LED under-kitchen-counter lights, etc -- can wipe out reception.   So be prepared to hunt out sources of RFI, and manage them.

Broadcast SW is dying, being replaced by the Internet.   See what you can find.  I'm out of touch with Internet SW directories, but I'm sure you'll find them.

.       Charles
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AF6WL
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Posts: 132




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« Reply #2 on: August 15, 2013, 10:30:44 PM »

With a short whip a simple manual antenna tuner e.g. MFJ-9201 will make an amazing difference.

For reception < 7MHz an active antenna whip will give better performance, especially if you can situate it on an outside wall away from the electrical hash of computers and TVs.
All you need is a J310,2N2222 and a handful of Rs and Cs.
The active antenna is essentailly what's built into portable SW RXs.
« Last Edit: August 15, 2013, 10:35:57 PM by AF6WL » Logged
WA2ONH
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Posts: 252




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« Reply #3 on: August 16, 2013, 08:51:52 AM »

Some other suggestions ...

1. Go to radio shack or whatever and get a 100 foot spool of wire. Connect one end to receiver and throw the other end out the window, into a tree if you've got one and listen to your hearts content. Afterwards, roll the wire back up to the spool until next time.

Listen to my Icom R-75 Rx that way and the wire is nearly invisible, especially at night.

An indoor antenna of any kind is subject to many sources of RFI be it TV, computer, lights etc.

2. There's also "WebSdr" world wide reception via the Internet.

A WebSDR is a Software-Defined Radio receiver connected to the internet, allowing many listeners to listen and tune it simultaneously. SDR technology makes it possible that all listeners tune independently, and thus listen to different signals; this is in contrast to the many classical receivers that are already available via the internet.  

LINK: http://websdr.org/

To satisfy that CW / SWL listening need, there's always a solution!  

Go for it and Good Luck!
« Last Edit: August 16, 2013, 09:09:43 AM by WA2ONH » Logged

73 de WA2ONH dit dit    ...Charlie
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"No time is ever wasted that is spent LEARNING something!"
AD0AE
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Posts: 78




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« Reply #4 on: August 16, 2013, 09:14:58 AM »

WA2ONH - Thank you for that response about the SDR!  That is a really useful little link!  I am going to check that out.
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N4NYY
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Posts: 4745




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« Reply #5 on: August 16, 2013, 09:45:15 AM »

Some other suggestions ...

1. Go to radio shack or whatever and get a 100 foot spool of wire. Connect one end to receiver and throw the other end out the window, into a tree if you've got one and listen to your hearts content. Afterwards, roll the wire back up to the spool until next time.



Yep. If RX, this is the way I would go. I start at 30 feet minimum, more if possible. 100 feet would be great. FYI, there are from receivers that come in portable kit form, and have a retractable wire in a spool for an antenna. May be Sangean. Don't recall.
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N3DT
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Posts: 514




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« Reply #6 on: August 19, 2013, 03:28:40 PM »

There were periods in the past when the sunspots were hot and reception was great, and the foreign stations were really powerful.  Things have changed, there's a lot more QRM and the signals seem weaker and fewer, plus we're in a not so great sunspot cycle, so I'd put as much antenna outside as you can get.  Or listen on the interweb.  But what fun is that?  No serendipity.
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N0IU
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Posts: 1266


WWW

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« Reply #7 on: August 20, 2013, 04:28:35 AM »

The most comprehensive SW list is from NASWA, the North American Shortwave Association. Their website is: http://www.naswa.net/. In order to get their spreadsheet, you have to join their Yahoo group: swskeds. They have a huge, I mean really HUGE spreadsheet of shortwave stations.

So what is huge? 22 columns which break down everything from time, country of original, language and everything else you would want to know. Now here's the huge part... there are over 23,700 rows of information! Being in spreadsheet form, you can break it down by time, frequency, language, etc.

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