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Re: Topband: TX/ RX Antenna Switching

To: Tom W8JI <w8ji@w8ji.com>, topband@contesting.com
Subject: Re: Topband: TX/ RX Antenna Switching
From: Grant Saviers <grants2@pacbell.net>
Date: Thu, 15 Nov 2012 12:55:26 -0800
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Tom,

Thanks for all your contributions and comments. I searched the DXE web site and was unable to find the limiter you mentioned. Could you be more specific?
Also, a clarification about data on your web site re the RDF table in 
the "How low noise receiving antennas really work" page - I assume the 
"small 4 square" refers to a designs (yours) such as the DXE active 4 
and 8 squares with whip antennas.  Could you confirm that?
I'm considering 80/160 receiving antennas and have the space for three  
Beverages 0.75 to 1.0wl 160m long bidirectional (NE/SW, E/W, NW/SE) made 
from coax, QTH is Redmond, WA.  Also, I'm considering the DXE 4 and 8 
square active arrays with a radius of 0.15 wl (80') on 160m but can't 
get more than about 1/4 wl from a 160m vertically polarized delta loop.  
My 80m rotatable dipole is at 100' up and the tower base at least 100' 
from the nearest 8 square antenna, so hopefully that interaction is minimal.
Your inputs would be appreciated.

Grant Saviers KZ1W


On 11/14/2012 5:07 AM, Tom W8JI wrote:
By the way Buck, there is more to this than some people will tell you.

The DXE switch uses a unique RF limiter that kicks in hard at about 23 dBm. Below that level there is no intermod at all!! It will not deteriorate the receiver, like normal cheap back-to-back diode systems.
If you need a receiver limiter and do not want to hurt receiver 
dynamic range on modern receivers, it takes far more circuitry than 
cheap back-to-back diodes.
73 Tom
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