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 Antennas
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 Return to top of page · Post #: 1 · Written at 8:35:11 PM on 29 January 2018.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 2154

Does anyone here have a design for a efficient long distance antenna. Whether it be active loop or other. I would like to know how to get the best signal. Even if its a commercially available kit please.


 
 Return to top of page · Post #: 2 · Written at 3:04:37 PM on 30 January 2018.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 2369

What frequencies Carl??


 
 Return to top of page · Post #: 3 · Written at 3:07:22 PM on 30 January 2018.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 2154

AM or shortwave. I just wish to get the best out of my antique radios.


 
 Return to top of page · Post #: 4 · Written at 3:55:29 PM on 30 January 2018.
Johnny's avatar
 Location: Hobart, TAS
 Member since 31 July 2016
 Member #: 1959
 Postcount: 544

As long a piece of wire as you can get, then a matching/tuner to the radio.
RTH had a passive project which would suit you purposes, and also an active one with as I can remember one transistor RF amp.
When I get a chance will try to find these RTH projects.
Maybe early 60's or 70's.
JJ


 
 Return to top of page · Post #: 5 · Written at 4:35:36 PM on 30 January 2018.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 2369

I have a big problem with high levels of noise at my place, that seems to emanate from the basement power switchroom for the building. But up at the back fence it's fairly quiet. So I ran some RG59 along the side fence and some hookup wire along the timber back fence (suburban townhouse, backs onto Forest Way). Hookup wire connected to co-ax inner, shield to ground at radio end, inner to antenna.

Result: Noise nearly gone, signal strength rolls off as you go up the band. A good result, I can now actually listen to 630 and 702! Previously my S:N on 702 was 0 db (i.e. noise equal to signal - actually it's a bit worse than that), now about 30db.

It needs a proper matching transformer and the shield grounded at the antenna end.

JJ, I'd be interested in that too, when you find it.


 
 Return to top of page · Post #: 6 · Written at 5:49:11 PM on 30 January 2018.
Tinkera123's Gravatar
 Location: Melbourne, VIC
 Member since 5 October 2009
 Member #: 555
 Postcount: 465

Yep, me too, please.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
Cheers, Ian

 
 Return to top of page · Post #: 7 · Written at 7:34:13 PM on 30 January 2018.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 2154

Sounds like what I need


 
 Return to top of page · Post #: 8 · Written at 8:16:29 PM on 30 January 2018.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5254

The Yaesu 7700 has an antenna attenuator & Impedance matching box. Damn good if you can find one. I do have an RCA pdf on antenna lengths. There is such a thing as a long wire antenna that is too long.

I am rural, the Yaesu was operating at one stage on a 50m long wire antenna. Workshop; currently around 20m & that brings in 2CH (with some fading) here 520 Km (as the crow flies: Night).

These are extremely elaborate affairs, using farm electric fence (7KV) insulators & 2.5mm fencing wire as the active element. Down-lead is clamped with electric fence line taps, but does have a terminal in the end of the external wire. Seeing that we discontinued the over-head power line I now have its insulators, for any new antenna.

Tension in the 50m one was maintained by what is loosely described as halyard & dead weight. That allowed some give when hit by flying objects.

Marc


 
 Return to top of page · Post #: 9 · Written at 8:36:42 PM on 30 January 2018.
Johnny's avatar
 Location: Hobart, TAS
 Member since 31 July 2016
 Member #: 1959
 Postcount: 544

OK, A quick look at the index. As regards antenna/aerial tuners/couplers, pre amps, improvements for B/C reception ect.

RTH
April 1948 pge 35
Aug 1952 pge 36
July 1953 pge 76
Jan1957 pge 40
June 1957 pge 89

EA
Jan 1968 pge 40
Oct 1976 pge 63
July 1979 pge 49
Aug 1990 pge 152
Nov 1991 pge 74 (pre amp)
Dec 1995 pge 58 (active ant)
Nov 1996 pge 58 (AM loop ant)
Nov 1998 pge 64 (broadcast band ant tuner)

Happy browsing,
JJ


 
 Return to top of page · Post #: 10 · Written at 8:44:25 PM on 30 January 2018.
Johnny's avatar
 Location: Hobart, TAS
 Member since 31 July 2016
 Member #: 1959
 Postcount: 544

Additional info,
At home for mainly Amateur radio I use a large loop antenna.
This is via an open feeder line to balanced tuner, hence to receivers and TX's.
Being a totally balanced system it is noise cancelling, and being as large as the block can handle, is vey useful even right down to the broadcast frequencies.
JJ


 
 Return to top of page · Post #: 11 · Written at 8:59:47 PM on 30 January 2018.
STC830's Gravatar
 Location: NSW
 Member since 10 June 2010
 Member #: 681
 Postcount: 1256

Found these links in June '17. Might be informative.

http://vintage-radio.com.au/default.asp?f=2&th=812


 
 Return to top of page · Post #: 12 · Written at 4:45:12 PM on 31 January 2018.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6686

The Yaesu 7700 has an antenna attenuator & Impedance matching box

It's the FRT-7700. I have one for my FRG-7700 receiver.


 
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