British Telecom also used LPAs to provide global broadcasting from Rugby
Radio Station.
EUGENE SMAR wrote:
>TT:
>
> FWIW: Back in the late 80's I was involved with designing a relay
>station for VOA in the Negev Desert in Israel. The intended application was
>to receive satellite-borne audio from Washington DC studios and retransmit
>the material to south-central Asia (Afghanistan, Kyrghystan, Kazahkstan,
>etc.) The US-based transmitters couldn't broadcast to that area directly
>due to Soviet jammers. The main transmit array was a series (three, I
>think) of curtain arrays that could be slewed a few degrees in azimuth and
>elevation by changing the phasing of the feeds. The arrays were to be
>supported between towers that were three hundred feet tall. (Antenna area
>was measured in acres, not square feet!) I believe Saber was the intended
>manufacturer, but I could be mistaken. The transmitters (Continental among
>other mfrs) were going to be 100 kW jobs and the ERP was enormous (I can't
>recall the figures.)
>
> The site was also going to include a large LPDA for 6 - 30 MHz up at
>100 feet on a rotator (SS, here I come!) This antenna was a backup for the
>programming, in case the satcom feed failed. It was also going to be used
>with a "QRP" 50 kW transmitter for order wire comms for TTY and who knows
>what else.
>
> The whole thing was going to be computer-driven based on propagation to
>the intended target sites and the program schedule. So basically I know of
>at least one SW broadcast facility that included both curtain arrays and
>LPDA's in its antenna line-up.
>
>73 de
>Gene Smar AD3F
>P.S. Then glasnost came along and Mr. Gorbachev silenced the jammers. The
>project was never constructed. Sigh.
>-----Original Message-----
>From: Pete Smith <n4zr@contesting.com>
>To: TOWERTALK@contesting.com <TOWERTALK@contesting.com>
To: <towertalk@contesting.com>
>Date: Saturday, November 16, 2002 2:44 PM
>Subject: Re: [Towertalk] Loop Gain (was LPA designs)
>
>
>
>
>>At 11:28 AM 11/16/02 -0600, Jon Ogden wrote:
>>
>>
>>>on 11/16/02 10:49 AM, Zyg Skrobanski at af4mp@mindspring.com wrote:
>>>
>>>
>>>
>>>>I don't think I've seen Yagi's used by any SW broadcasters.
>>>>
>>>>
>>>Probably not. It's too narrow in bandwidth and probably too directional.
>>>
>>>
>>>
>>Actually, when I lived in Taiwan in the late 1960's, there was a religious
>>broadcasting station there that used a three-element tribander (modified
>>for BC frequencies, I assume) to broadcast to the mainland. The quad
>>parasitic array was, I believe, developed at broadcast station
>>HCJB. Today, VOA et al frequently make use of curtain arrays that,
>>depending on their configuration, can be very directional indeed. One of
>>the other things that is (or was) on the F12 web site was N6BT's
>>description of using a 21 dBi gain broadcast curtain in a DX contest.
>>
>>
>>73, Pete N4ZR
>>Sometimes a tower is just a tower
>>
>>
>>
>>
>>_______________________________________________
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>>See http://www.mscomputer.com
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>>
>>
>
>_______________________________________________
>AN Wireless Self Supporting Towers at discounted prices,
>See http://www.mscomputer.com
>
>Wireless Weather Stations now $349.95. Call Toll Free,
>888-333-9041 for additional information.
>_______________________________________________
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>Towertalk@contesting.com
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>
>
>
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