Topband: We need better preamps for 160 because FT8 activity

n0tt1 at juno.com n0tt1 at juno.com
Tue May 23 22:04:24 EDT 2023


"Any new ideas on high performance preamps for 160m?? "

The only thing I can suggest is to build the front end of the
preamp as if it were a JW Miller style crystal radio, followed by the
amp itself.  Yep, crystal radio.  Those sets had a bandwidth of ~10khz.
Super selective and, yes, on 160m the user would have to retune often
when browsing the band.  Of course, a nice feature could be automatic
tracking.

73,
Charlie, N0TT  

On Tue, 23 May 2023 12:55:36 -0400 <n4is at comcast.net> writes:
> Hi Folks
> 
>  
> 
> I am following the conversation about LOG RX antennas, I understand 
> the pain
> from a noise city lot on 160m. it is hard. I am using Waller Flag's
> vertical, since 2006, and horizontal since 2010, however vertical 
> noise is
> so bad with new solar panels and EV charges , on top of LED lights, 
> that I
> no longer have my Vertical WF, it is inefficient  for a city lot. My 
> HWF is
> working very well.
> 
>  
> 
> The reason I started a new tread is what I noticed during the last 
> DX
> season. The number of KW station on 1840 is growing exponentially. 
> If you
> have 100 station with 1kW on a small portion of the band, it is 
> equivalent a
> 100 KW single station. Imagine 500 station, 500KW, My HWF preamp is 
> in use
> since 2010, my first QSO with my 6xBF981 preamp was XU7ACY, long 
> path (160m
> CW), from the same city lot, not so noise as it is today. However 
> now with
> the number of FT8 KW's, and most of them very bad linearity, with 
> phase
> noise several KHz on each side,  my old preamp IP3 is not strong 
> enough as
> it used to be.
> 
>  
> 
> I will be back to old NORTON's preamp on my station with new high Q 
> front
> end. With all the power of 100's FT8 station at the same time, the
> consideration for a new RX antenna and new preamplifier is raising 
> the bar
> on overall performance.
> 
>  
> 
> Any new ideas on high performance preamps for 160m?? We will need 
> it.
> 
>  
> 
> 73's
> 
> JC
> 
> N4IS
> 
>  
> 
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