[VHFcontesting] 2m SDR, anyone?
jamesduffey at comcast.net
Tue Nov 20 12:18:23 EST 2018
I can testify to the effectiveness of Keith’s 2M SDR setup. As a rover, often at 200+ miles distance from Keith, I just point the antenna in W9RM’s general direction and call CQ. He usually comes right back, assuming he isn’t running at a high rate on 6M. Often the signal level on my end is weak, so I appreciate the effort he puts in on monitoring 2M. He is often easier to raise on 2M than some locals. - Duffey
James Duffey KK6MC
Cedar Crest NM
> On Nov 20, 2018, at 11:00, vhfcontesting-request at contesting.com wrote:
> I always have a SDR running in the RX antenna loop of my FT-920 on
> 6M. I'm looking at it as I type this and can see the occasional beacon
> pop in on meteor scatter. I run it on the coupled arm of a Mini-Circuits
> 1-100 MHz coupler with a LNA and attenuators to equalize that loop with
> what I hear on the main antenna. I use HDSDR and the SDR is equal to the
> FT-920 in sensitivity almost exactly. Of course, the SDR is MUCH more
> subject to being "crunched" by strong signals, in and out of the band. The
> only BP filtering I use is what is native in the SDR (FM broadcast being
> one) and the inherent "filtering" of the antenna system.
> On 2M and above, I run transverters with 28 MHz IF's into a different radio
> and do the same thing with another SDR that looks at approx. +/-100
> kHz from 28.1 or 28.2 MHz, depending on what band I'm listening to. With
> this setup, I can see whats up on 2M when I'm working 6 during a contest,
> or during a intense Es opening. On 2M, I watch from approx 144.150 to
> 144.350 so I can see both activity and beacons, if they appear.
> Both SDR's are integrated with HDSDR and a mouse click on the HDSDR screen
> will tune the main radios to whatever freq the SDR is 'tuned' to. I run a
> separate computer on the IF radio for HDSDR and for WSJT, just in case I
> need to TX on both radios at once. There is very little activity on 2M and
> above here so the idea is to have a visual indication of those few contest
> Rovers that might show up or to see the first hint of potential Es on 2M
> without having to actually listen, which can be a distraction.
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