[Premium-Rx] FS: HF RECEIVER MULTICOUPLER (FROM DRAKE7-LINESTATION)

[Clemens Paul]

Hello Michael,

yes,you are of course absolutely right that in non-critical setups
as you have described a resistive splitter may be adequate.
I'm probably a bit spoiled by my experiences when trying to measure
high IP3s with two HP8640Bs.:-)
BTW the resistive delta splitter can be even more simplified by just
omitting one of the three 50Ohm resistors.
E.g. HP does this with their power splitter 11652-60009 which belongs to
the vintage 84067A VNA system.
Then you have to connect the antenna always to the junction of the two
resistors.But I'm sure you know this.
Just for fun I've measured another type of resistive splitter/combiner
which is the star configuration of three 16,7Ohm resistors.
Mine is made by R&S.
This combiner has the worst port isolation of all,i.e. 6dB.
The spiltters with the best port isolation are the 6dB hybrid types which
achive up to 45-50dB on HF.


73
Clemens
DL4RAJ


----- Original Message ----- 
From: "Michael O'Beirne" <michaelob666 at ntlworld.com>
To: "Clemens Paul" <cpaul at gmx.net>
Cc: "PREMIUM-RX" <premium-rx at mailman.qth.net>
Sent: Tuesday, April 24, 2012 11:49 PM
Subject: Re: [Premium-Rx] FS: HF RECEIVER MULTICOUPLER (FROM DRAKE7-LINESTATION)


>
> Dear Clemens
>
> Thank you for your email tonight.
>
> I agree entirely with your maths, but in some circumstances the much higher 
> port- to-port isolation of the hybrid may not be needed, for example using two 
> receivers at widely spaced frequencies in contrast to, say, critical receiver 
> testing for IP3 where you need to achieve the maximum isolation between the 
> two RF signal generators.
>
> 73s
> Michael
> G8MOB
>
> ----- Original Message ----- 
> From: "Clemens Paul" <cpaul at gmx.net>
> To: "Michael O'Beirne" <michaelob666 at ntlworld.com>
> Sent: Tuesday, April 24, 2012 6:58 PM
> Subject: Re: [Premium-Rx] FS: HF RECEIVER MULTICOUPLER (FROM 
> DRAKE7-LINESTATION)
>
>
>> Hello Michael,
>>
>>>A resistive delta or splitter can be built even
>>> more cheaply for the cost of 3 resistors, 3 BNCs and a small metal box.
>>
>> This is really a cheap solution, but also in terms of performance.
>> 3dB more loss than a 3dB hybrid splitter and what is much more important,
>> the resistive splitter has a poor port isolation of only 12dB while a good
>> 3db hybrid splitter/combiner offers ~35dB.
>>
>> 73
>> Clemens
>> DL4RAJ
>
>
>
> -----
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