The following is in response to an e-mail I posted on the MoonNet to ham
asking about equipment for EME.
Does anyone on this reflector have comments/responses to Leif's criticism of
Flex equipment?
Has anyone noted such performance?
73,
Bill Tynan, W3XO
Long-time and satisfied Flex 5000 user
----- Original Message -----
From: "Leif Asbrink" <[email protected]>
To: <[email protected]>
Sent: Sunday, March 17, 2013 9:03 AM
Subject: Re: [Moon-Net] Moon-net Digest, Vol 96, Issue 12
Hi All,
The Flex transmitters are very noisy at large
frequency separations. There is a noise maximum
about 300 kHz from the carrier frequency due to
inadequate filtering between the D/A converter and
the tx mixer. This is well visible in the ARRL
Lab reports in QST.
When you hear a noise maximum on 144.100 it is not
easy to figure out that it comes from a Flex transmitter
on 144.400 because the noise does not carry any
modulation and there is no noise within 50 kHz
or more from the main signal from the Flex.
Use only if you are not likely to produce signals more
than 70 dB above the noise for other band users.
Also, never use Flex at reduced power with transverters
because the noise is not reduced so it increases
relative to the signal. Use attenuators.
I will make full details public in the future.
73
Leif / SM5BSZ
On Sun, 17 Mar 2013 00:52:19 -0500
"Bill Tynan" <[email protected]> wrote:
Robert:
I'm not exactly an EMEer yet. I have one contact off the Moon on 6 meters
with W7GJ, but have been copied off the Moon by two other stations.
But, I will offer this. thought. Look into the Flex radios. They are
very
stable and can be locked to a 10 MHz source. Also, if you are going for
CW,
the filters are extremely good. You can go down to 25 Hz with no ringing.
If
you plan to use WSJT, you can get software from a guy in Russia called a
Virtual Audio Cable (VAC) that connects the radio and sound card without
any
of the clap-trap boxes and wires needed for digital modes with other
transceivers.
The Flex 1500 is the least expensive but only puts out 5 Watts. And, it
only
covers up to up to 6 meters. But, if since you're going to be using
transverters anyway, that's not a problem. The Flex 3000 is a full
featured,
physically small, transceiver which puts out 100 W on 160 thru 6 meters.
The
Flex 5000, which I have is similar in output but provides for
installation
of a second receiver.
You will need a pretty good computer to go with any of the Flex radios,
at
least a dual core and probably a quad core processor.
I hope this helps. Good luck.
73,
Bill Tynan, W3XO/5 EM00kd.
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