Re: Topband: RX PREAMPS

[Chortek, Robert L]

I have both systems. 

The DXE 2 element system is 80 and 100 feet from my transmitter antenna, 
respectively. I have run 1.5 kW for the last several years without any 
problems, and with no sequencer. 

The Hi-Z triangular system is even closer (65') and has never had a problem.

YMMV,

73,

Bob AA6VB

Sent from my iPhone

> On Nov 15, 2015, at 9:41 AM, Mike Greenway  wrote:
> 
> I  have used the HI Z rx system and also the DXE ones.  HI Z said in the past 
> no need for a sequencer to get power off the amps if the xmit ant was close 
> to the rx system antennas.  Close I would say 60 foot.  DXE has always 
> suggested using a sequencer to get power off the amps during xmit.  I am 
> going to be forced to move a DXE system within 65 ft or so of my 160 vertical 
> and wonder if anyone has had any experience of using the DXE without a 
> sequencer close to their xmit antenna.  Just hate to install one more thing I 
> could get around but will if absolutely necessary.  I know moving it closer 
> is not an ideal situation but you do what you have to.  Any input?  73 Mike 
> K4PI
> _
> Topband Reflector Archives - http://www.contesting.com/_topband
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Re: Topband: RX PREAMPS

[Tom W8JI]

I  have used the HI Z rx system and also the DXE ones.  HI Z said in the 
past no need for a sequencer to get power off the amps if the xmit ant was 
close to the rx system antennas.  Close I would say 60 foot.  DXE has 
always suggested using a sequencer to get power off the amps during xmit. 
I am going to be forced to move a DXE system within 65 ft or so of my 160 
vertical and wonder if anyone has had any experience of using the DXE 
without a sequencer close to their xmit antenna.  Just hate to install one 
more thing I could get around but will if absolutely necessary.  I know 
moving it closer is not an ideal situation but you do what you have to. 
Any input?  73 Mike K4PI

_



You actually have to try it and see. Interaction depends on the very fine 
details of the system, including cable lengths and the transmitter system 
does to the feedline when on RX and how the RX antenna couples to the TX 
antenna. As such, there will never be one universally true answer, so asking 
others won't really tell you how it will work with your system.


I do know that what Hardy said is basically correct. It models that way, it 
works the way he described.


If I place any RX vertically polarized antenna around my 160 TX antenna, 
even if the RX antenna is 250 feet or further away, I can always see a 
substantial interaction with certain termination changes in the TX antenna 
array when receiving. The only exception is if the RX antenna design nulls 
coupling to the TX antenna.


An RX antenna cannot be designed to be immune at such close spacings, unless 
it places a pretty deep null in the direction or in the polarization of the 
TX antenna.


So you have multiple things affecting how it will work:

1.) How your system terminates your TX antenna when on RX

2.) If the RX antenna nulls the TX antenna, either by pattern and/or by 
polarization


3.) What level damages things or affects things

4.) What else is around

5.) What people call good enough

and so on.

Since no two systems are identical in every single way, you just really have 
to try it.


73 Tom 


_
Topband Reflector Archives - http://www.contesting.com/_topband

Topband: RX PREAMPS

[Mike Greenway]

I  have used the HI Z rx system and also the DXE ones.  HI Z said in the past 
no need for a sequencer to get power off the amps if the xmit ant was close to 
the rx system antennas.  Close I would say 60 foot.  DXE has always suggested 
using a sequencer to get power off the amps during xmit.  I am going to be 
forced to move a DXE system within 65 ft or so of my 160 vertical and wonder if 
anyone has had any experience of using the DXE without a sequencer close to 
their xmit antenna.  Just hate to install one more thing I could get around but 
will if absolutely necessary.  I know moving it closer is not an ideal 
situation but you do what you have to.  Any input?  73 Mike K4PI
_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: RX PREAMPS

[Hardy Landskov]

Mike,
It's your bud from Dayton. I will make this comment: I have modeled 160 rx
antenna systems, Hi-Z 4 square and 8 Circle on EZNEC with the NEC-4 engine.
Anything closer than 200 feet with a 160 tx antenna results in severe
pattern distortion. Also measured +3 to +20 dBm coming into the K3 rx port
depending on direction. I would imagine DXE arrays would be similar.
YMMV.
73 Hardy N7RT


-Original Message-
From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Mike
Greenway
Sent: Sunday, November 15, 2015 10:34 AM
To: TOPBAND
Subject: Topband: RX PREAMPS

I  have used the HI Z rx system and also the DXE ones.  HI Z said in the
past no need for a sequencer to get power off the amps if the xmit ant was
close to the rx system antennas.  Close I would say 60 foot.  DXE has always
suggested using a sequencer to get power off the amps during xmit.  I am
going to be forced to move a DXE system within 65 ft or so of my 160
vertical and wonder if anyone has had any experience of using the DXE
without a sequencer close to their xmit antenna.  Just hate to install one
more thing I could get around but will if absolutely necessary.  I know
moving it closer is not an ideal situation but you do what you have to.  Any
input?  73 Mike K4PI _ Topband Reflector Archives -
http://www.contesting.com/_topband

_
Topband Reflector Archives - http://www.contesting.com/_topband

Topband: rx preamps

[Jim]

Martin is the latest incarnation of the infamous W7IUV preamp?  and do you know 
anyone that has PC boards before I reinvent the wheel and make another one? 
Jim  WA3MEJ 

- Original Message -

Message: 10 
Date: Fri, 28 Aug 2015 23:53:10 +0200 
From: Martin Kratoska  mar...@centrum.cz  
To: topband@contesting.com 
Subject: Topband: W7IUV preamp 
Message-ID:  55e0d846.3070...@centrum.cz  
Content-Type: text/plain; charset=windows-1252; format=flowed 

The latest version 6 

http://www.okdxf.eu/files/preamp_r60.pdf 

73, 
Martin, OK1RR 

_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: rx preamps

[Martin Kratoska]

Yes, it is the latest version AFAIK. BTW the PCB is in process, it 
should be double sided, ready for production at Seeed Studio or other 
professional PCB maker. It is not needed for a single unit, WD8DSB has a 
good design well suited for home production. If there interests enough, 
I finalize my design and order the boards. Contact me on my private email:

mar...@ok1rr.com
or
mar...@centrum.cz

73,
Martin, OK1RR

Dne 29.8.2015 v 21:26 Jim napsal(a):

Martin is the latest incarnation of the infamous W7IUV preamp?  and do you know 
anyone that has PC boards before I reinvent the wheel and make another one?
Jim  WA3MEJ

- Original Message -

Message: 10
Date: Fri, 28 Aug 2015 23:53:10 +0200
From: Martin Kratoska  mar...@centrum.cz 
To: topband@contesting.com
Subject: Topband: W7IUV preamp
Message-ID:  55e0d846.3070...@centrum.cz 
Content-Type: text/plain; charset=windows-1252; format=flowed

The latest version 6

http://www.okdxf.eu/files/preamp_r60.pdf

73,
Martin, OK1RR

_
Topband Reflector Archives - http://www.contesting.com/_topband



_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: rx preamps

[Don Kirk]

Hi Jim,

You might want to check out my website that shows my builds of the W7IUV
preamp and the URL is http://sites.google.com/site/rxpreamps/.  You can
download my simple artwork for the circuit board on my website (at the
bottom of the page), and I just used a Dremel tool to make the traces.

Don (wd8dsb)



On Sat, Aug 29, 2015 at 3:26 PM, Jim wa3...@comcast.net wrote:

 Martin is the latest incarnation of the infamous W7IUV preamp?  and do you
 know anyone that has PC boards before I reinvent the wheel and make another
 one?
 Jim  WA3MEJ

 - Original Message -

 Message: 10
 Date: Fri, 28 Aug 2015 23:53:10 +0200
 From: Martin Kratoska  mar...@centrum.cz 
 To: topband@contesting.com
 Subject: Topband: W7IUV preamp
 Message-ID:  55e0d846.3070...@centrum.cz 
 Content-Type: text/plain; charset=windows-1252; format=flowed

 The latest version 6

 http://www.okdxf.eu/files/preamp_r60.pdf

 73,
 Martin, OK1RR

 _
 Topband Reflector Archives - http://www.contesting.com/_topband
_
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