[Elecraft] Seperate Receive Antenna

[jim]

There was a schematic published by LZ1AQ that showed the implementation of a loop required that one of the inputs of the amp was referenced to ground.

Jim

-----Original Message-----
From: David Cutter [mailto:d.cutter at ntlworld.com] 
Sent: Sunday, February 1, 2015 11:59 AM
To: Mike va3mw; jim
Cc: elecraft at mailman.qth.net; Wouter Jan Ubbels
Subject: Re: [Elecraft] Seperate Receive Antenna


Jim

How did you determine that the LZ1AQ amplifier is not a differential amp? 
the diagrams lead me to believe that it has differential inputs.  Page 29 shows the specification item 10 which states that the inputs are balanced. 
What am I missing, where should I be looking?

73

David
G3UNA


>> On Jan 31, 2015, at 6:02 PM, jim <jbollit at outlook.com> wrote:
>>
>>
>> The LZ1AQ amplifier is NOT a differential input amp, rather it is 
>> referenced to ground.
>>
>> This can have significant issues as it relates to common mode noise.
>>
>> As a result of my research, I ended up with a Pixel loop.  The amp 
>> has great characteristics, differential input, uses an A.C.  wallwart 
>> for low noise, and the install instructions isolate the amp from any ground.
>>
>> The loop interface also has a control line input from your rig, that 
>> controls an internal relay, so the amp is protected when you transmit.
>> The loop was designed by hams.
>>
>> The mechanical design of the loop is excellent, using welds at the 
>> aluminum joints.
>>
>> I have no interest in the Pixel company, just a very satisfied customer. 
>> So satisfied, I bought two of them and phase them with a DX 
>> Engineering
>> NCC-1 phaser.
>>
>> Jim
>> W6AIM
>>
>>
>>
>> -----Original Message-----
>> From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of 
>> Wouter Jan Ubbels
>> Sent: Saturday, January 31, 2015 12:28 PM
>> To: elecraft at mailman.qth.net
>> Subject: Re: [Elecraft] Elecraft Digest, Vol 129, Issue 41
>>
>> Hi Paul,
>>
>> I can recommend LZ1AQ´s active loop antenna.
>> See
>>
>> http://active-antenna.eu/
>>
>> It offers a nice variety of antenna configuration options, and it 
>> plays very well here as a separate RX antenna at my urban & noisy 
>> QTH. The unit is of high quality, and very well documented.
>> I am using it with my KX3 and a homebrew switchbox which uses reed 
>> relays for QSK switching, controlled by the KX3 PTT output taken from 
>> the ACC2 jack.
>>
>> 73,
>>
>> Wouter Jan PE4WJ
>>
>>
>>
>>> Message: 2
>>> Date: Fri, 30 Jan 2015 19:15:32 +0000
>>> From: Paul Barlow <paul.barlow at upcmail.ie>
>>> To: <elecraft at mailman.qth.net>
>>> Subject: [Elecraft] Separate Receiving Antenna
>>> Message-ID: <DUB405-EAS19886EB1DCCD9A8D869E61994310 at phx.gbl>
>>> Content-Type: text/plain; charset="us-ascii"
>>>
>>> Dear Elecrafters,
>>>
>>> I have a very small and odd shaped garden in which to play Ham Radio.
>>> I have a K3 (and a K2 and... ), I run QRP CW and I was wondering if 
>>> anyone had experience of using active loop antennas as receiving 
>>> antennas to lower the noise floor. I was looking at Wellbrook's 
>>> Website this afternoon, and I see that their loops get good reviews 
>>> on EHam. I was wondering what experience you guys might have with 
>>> these and similar antennas.
>>>
>>> 73, Paul EI5KI
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