Topband: Passive Receive Antenna Splitter

Tom W8JI w8ji at
Sun Mar 16 10:29:17 EDT 2014

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 at>
To: <topband at>
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
> blog at
> For spots, please go to your favorite
> ARC V6 or VE7CC DX cluster node.
> 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:
>> 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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