Topband: TX/ RX Antenna Switching

[Grant Saviers]

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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> Topband reflector - topband at contesting.com
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