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Re: Topband: Passive Receive Antenna Splitter

To: "Pete Smith N4ZR" <n4zr@contesting.com>, <topband@contesting.com>
Subject: Re: Topband: Passive Receive Antenna Splitter
From: "Tom W8JI" <w8ji@w8ji.com>
Reply-to: Tom W8JI <w8ji@w8ji.com>
Date: Sun, 16 Mar 2014 10:29:17 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>
People also have to be careful with systems.

The "resistor on center tap" splits the signal, but runs the ports out-of-phase. This is OK when you need a 180 flip between port, or you don't care about phase, but it can get you in trouble in many cases.

Also, the very same thing that makes it good wideband system, tight coupling between the common and load windings, also tends to make the splitter misbehave at higher frequencies. This is what the "one transformer" splitter never became real popular in extremely wide bandwidth systems.

----- Original Message ----- From: "Pete Smith N4ZR" <n4zr@contesting.com>
To: <topband@contesting.com>
Sent: Saturday, March 15, 2014 5:44 PM
Subject: Re: Topband: Passive Receive Antenna Splitter


Typically the CATV splitters are marked 5-1000 MHz or similar. I've often wondered how much rolloff there was beyond the basic 3-4 dB down at topband. I have a Clifton that I built myself, but have not been able to achieve the insertion loss and isolation specs - which may well be my fault.

73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
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On 3/13/2014 11:07 PM, Joe Subich, W4TV wrote:

I use a couple of old CATV splitters for general purposes around here
and can't measure any excess (more than 3 - 4 dB) loss from common to
either port.

If you want a known good design to build some of your own, try:
   http://cliftonlaboratories.com/z10050a_3_db_hybrid.htm

73,

   ... Joe, W4TV


On 3/13/2014 9:13 PM, Gary K9GS wrote:
Can anyone point me to a design for a splitter for sharing a Beverage
antenna between two receivers?  This is for Field Day so these are not
optimized Beverages by any means.

Just want to allow the 80/40M stations to share antennas. Nothing fancy.

My thoughts are to just use a CATV "2-Way" splitter at the output of the
Beverage matching transformer and run separate feed-lines to each radio.
I'm pretty sure these things work down to 1 MHz but have not measured
them. I can use the pre-amp in the radio (K3) to compensate for the loss.

Thoughts?

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