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Farthest radio transmission??


The beamwidth of the antenna is amazing. A three element Tri-band HF yagi (20m,15m,10m) beamwidth is around 60-70 degrees with about 7 dbi of gain.

Below is a diagram of the Voyager's 12ft. parabolic antenna. Notice the X-band beam width and gain. The precision needed to point that antenna from 15.5 billion miles away is astonishing. Radio signal takes over 23 hours to travel from the spacecraft to Earth.



Voyager Beamwidth.jpg
 
I couldn't find much about the specifications of DSS 43. I found some general info on Wikipedia.

"Originally constructed as a 64 m dish in 1973 and enlarged in 1987. It is the largest steerable parabolic antenna in the Southern Hemisphere. It is used by NASA to communicate with Voyager 2; the only antenna remaining on Earth capable to do so. The antenna weighs more than 3000 tonnes and rotates on a film of oil approximately 0.17mm thick. The reflector surface is made up of 1,272 aluminium panels with a total surface area of 4,180 square metres.

dss43-1_fs.jpg


Canberra_Deep_Dish_Communications_Complex_-_GPN-2000-000502.jpg
 
The space craft itself is around the 22-23 watt range!
That's really incredible! With the antennas 48dB gain, that would give quite a substantial ERP............in the tens of thousands of watts, all focused into one insanely tight beam. The part I find amazing is that the spacecraft can maintain position and trajectory accurately enough to keep the antenna pointing at a very very very distant Earth. It's all pretty mind boggling really!
Makes my 12 watt sideband contact with New Zealand look like child's play by comparison LOL! :oops:
 
The Voyager craft design started in the early 1970's based on the Pioneer 10 program. No computer aided drafting back then. Pencil, paper, slide rules, and the gray matter of some very smart people designed these incredibly complicated machines.

Of course the RF amplifiers on the Voyager have a few tube amplifiers. What I didn't know is that the Travelling Wave Tube (TWT) amplifiers are still in production and being used in new satellites.

Here is a lnk to a NASA article about Traveling-Wave Tubes

Here is an article explaining the telecommunications equipment on the Voyager craft. I don't know the date of the article. Voyager Telecommunications

This is a 1970's era device. It is seems fitting that it uses an single eight-track digital tape recorder (DTR) and it still works!
 
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