Congrats and nice work!
Happy 4th!
Bob
N4HY
Phillips wrote:
Bob,
Close out report...
I build a Hi-pass filter to the design that Gary Breed used for his K9AY
pre-amp front end - the schematic is at:
http://www.aytechnologies.com/TechData/FilterPreamp_160-80.pdf
I haven't had a chance to run this on a Network Analyzer yet it's the
same design I've used in the past with my K9AY loop.
I put the filter into the RX1 receive loop and it nails the 40m BCI
stone dead - the filter has > 50dB attenuation on AM860 (which today is
coming in at -15 dBm on the inverted L!). I can't detect the loss on
frequencies > 1.8 MHz - from looking at the return loss with an antenna
analyzer, I'm guessing its 2dB or so - pretty flat to 50 MHz.
Of course, the box and connectors cost more than 10x the actual
components... not counting my time, still a cheaper solution than
buying a commercial version.
I suppose there is a good explanation as to why the FLEX 5000 needs this
additional filter OUTBOARD... a small annoyance that hasn't detracted
from the appreciation of a very fine piece of technology.
Perhaps at some point FLEX can incorporate this on the switching matrix
where the cost of the additional components would be < $1.
So - case closed for me on the BCI.
73's Stu N6TTO
-----Original Message-----
From: Bob McGwier [mailto:rwmcgw...@gmail.com]
Sent: Thursday, July 02, 2009 6:17 PM
To: Stu Phillips
Cc: flexradio@flex-radio.biz
Subject: Re: [Flexradio] PowerSDR "freeze" and AM Broadcast spurii on
40m with Flex-5000?
Stu:
WOW, those are some signals.
Yes, you will need the BCI filter. The front end is being hit pretty
hard. And yes, you can put it into the loop and it will work perfectly.
You have entirely too much gain in the radio for 160m-40m anyway so
there will be no degradation.
Try the buffer settings in the driver control panel to improve your
sensitivity to stalls in your computer.
Good luck!
Bob
N4HY
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