[Premium-Rx] phasenoise.xls

[Carcia, Frank A. HS]

Hi All,
The nice feature of the ARRL method is leakage around filters and cables
reduces the performance.
This will also happen in real world when there is
a strong signal. The Hot Rod 6830 and the stock unit have the same front end
but the performance
is quite different. This shows it takes more than dynamic range to get real
performance. My first
RX project was an old Heath SB303 with a 67 dB 
dynamic range. I increased it to 85 dB with many
modifications. I got to a point where signal leakage limited performance and
learned about
shielding the hard way.
I had a chance to check out Mark's 2050 power supply. I know the open frame
well and not surprised by the thermal problems. The supply was mounted
properly but the surface facing up should
connect to a heat sink. I thought about it a bit
and think a slab of copper between the top surface of the supply and the top
cover would pull the heat off power supply chassis. I've heard reports
of excessive unregulated voltage. A trick I've seen is to reduce the value
of the filter caps
and allow higher unregulated ripple that will
reduce heat across the pass transistors. Mark had
selected the highest tap on his RX but the heat sink was quite warm with the
cover removed after
about 20 minutes of operation. I looked at all
surface area of the cover and side rail and think
the problem could be solved with a thermal connection to the cover or side
rail. fc  

-----Original Message-----
From: Mark Donaldson [mailto:mark.donaldson at third-rail.net]
Sent: Monday, August 04, 2003 5:21 PM
To: Carcia, Frank A. HS; Mark Donaldson (E-mail); Premium-Rx (E-mail)
Subject: RE: [Premium-Rx] phasenoise.xls


The WJ receiver used in Frank's measurements was a WJ 8718A not a WJ 8717.
 
MD

	-----Original Message----- 
	From: Carcia, Frank A. HS [mailto:francis.carcia at hs.utc.com] 
	Sent: Mon 8/4/2003 4:35 PM 
	To: Mark Donaldson (E-mail); Premium-Rx (E-mail) 
	Cc: 
	Subject: [Premium-Rx] phasenoise.xls