[CQ-Contest] Multiple direction antennas on one radio...why?
e73m at e73m.com
e73m at e73m.com
Thu Oct 20 01:14:43 PDT 2011
Yes Igor, I guess any stack match can be used.
Here is another commercial product, note the underlined text:"Those
splitters are use at different contest-stations worldwide !
link is here http://www.qro-shop.com/Powersplitters.htm
73 Danny E73M
On Thu, 20 Oct 2011 09:58:01 +0600, Igor Sokolov wrote:
> Danny, Microham stack switch can split into 2 or 3 amp
> Then one can split output of each amp into 2 or 3 antenna with
> anpther stack switch.
> 73, Igor UA9CDC
> ----- Original Message ----- From: <e73m at e73m.com>
> To: <cq-contest at contesting.com>
> Sent: Thursday, October 20, 2011 5:48 AM
> Subject: Re: [CQ-Contest] Multiple direction antennas on one
>> Update, I found the other place to buy splitters, even for 4 amps,
>> 73 Danny E73M
>> On Wed, 19 Oct 2011 00:30:48 -0400, Tom W8JI wrote:
>>> This has my curiousity.....does anyone know what stations doing
>>> When I have a splitter, power divides from the exciter. Each amp
>>> gain. If I have one 10 dB gain amp and a 100 watt exciter I have
>>> If I split the power into two 10 dB amplifiers, I have 500 watts
>>> minus splitter losses. If I split it four ways, I have less than
>>> per amp. It doesn't matter if I split before the amps or after,
>>> except for
>>> the size of the splitter.
>>> I would either have to have a variable gain amplifier driving the
>>> that would increase power into the splitter just over 3 dB for
>>> split, or I'd have to have dummy loads and replace amplifiers with
>>> loads as I pulled antennas out of line.
>>> How do they do it?
>>> On receiving, summing receive signals from four antennas in
>>> directions would hurt MDS, because at minimum every additional pair
>>> antennas would decrease receiver S/N by at least 3 dB. There would
>>> least 6 dB of S/N loss and probably more in most cases.
>>> Why would someone do that?
>>> Or do they really use four radios with four amplifiers and four
>>> and transmit on all and only listen on one???
>>> Does anyone actually know how these systems really work, because it
>>> pretty strange to me on the surface. Are these systems planned, or
>>> a case
>>> of just throwing something at the wall and hoping more sticks to
>>> than falls off?
>>> One way it would work well is with four listening operators on four
>>> receivers so there is no S/N loss, and one transmitter at a time
>>> driving all
>>> four amps through one additional amplifier so there is minimal
>>> distortion if someone hears more than one TX antenna at once.
>>> I'm just trying to learn something useful here. I would never think
>>> running four antennas in different directions into one radio for
>>> except as a last possible resort.
>>> 73 Tom
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