Re: [IRCA] Elad FDM-S2 initial testing

[Chuck Hutton <charlesh3@xxxxxxx>]

Guy -


It really doesn't take much of a flash drive or SD card to keep up with SDR (Perseus) recordings. Perseus needs 64 mb/s (megabits) or 8 MB/s when recording 1.6 MHZ worth of signals. Almost any SD or flash can do that. Even the slowest flash drive in the link you sent handles 400 mb/s.


In the real world, I've not had a problem with using garden variety SD cards. Units that support SDXC (over 32 G) are common and I put a 128 GB SD in my T100TAF.

To me, the problem with the 1 USB port tablets is that with most, you can't connect a Perseus and charge the unit at the same time. Of my tablets, only my Dell Venue 8 Pro lets me do both via an adaptor. I'd love to hear about other devices that support this. It's part of the USB charging specs to allow this, so maybe more manufacturers will hop on the bandwagon.

Chuck
________________________________
From: IRCA <irca-bounces@xxxxxxxxxxxxxxxx> on behalf of Guy Atkins <dx@xxxxxxxxxxxxx>
Sent: Wednesday, March 8, 2017 10:04 PM
To: Mailing list for the International Radio Club of America
Subject: Re: [IRCA] Elad FDM-S2 initial testing

Hi Mark,

I can second what Chuck has said-- modern Atom processors can handle SDRs
with CPU cycles to spare as long as you don't go crazy and try to run too
many programs at once.

I have a Asus T100TA Transformer tablet/keyboard combination that has the
Bay Trail-T Z3740 processor and runs my FDM-S2 well, including MW recording
to an external SSD. I haven't used this combo since last fall and don't
recall the CPU percentage when recording or playing back files.

Here's a YouTube video I made of an older HP Stream 7 tablet (Atom Z3735)
running the Elad SDR, at around 13% CPU:
https://www.youtube.com/watch?v=6FAwxwI95Zg
[https://www.bing.com/th?id=OVP.Ve14a0d986e342656a887607498df015b&pid=Api]<https://www.youtube.com/watch?v=6FAwxwI95Zg>

HP Stream 7 - Elad FDM-S2 SDR Demo<https://www.youtube.com/watch?v=6FAwxwI95Zg>
www.youtube.com
This short video demonstrates that the Elad FDM-S2 software defined radio runs well on the $99 HP Stream 7 Windows 8.1 tablet. In the demo the entire medium ...




It's worth noting that the other external bits and pieces needed to run a
WAV file recording, Atom tablet or laptop powered SDR setup can be fiddly,
with OTG adapters, possibly powered USB hubs, and external drives and
cables. However, I've found that the faster MicroSD cards or USB flash
drives like this Sandisk Extreme model
<http://thewirecutter.com/reviews/the-best-usb-3-0-thumb-drive/> can
[http://thewirecutter5.wpengine.netdna-cdn.com/wp-content/uploads/2016/02/02-usb-thumb-drives-sandisk-extreme-cz80.jpg]<http://thewirecutter.com/reviews/the-best-usb-3-0-thumb-drive/>

The Best USB 3.0 Flash Drive | The Wirecutter<http://thewirecutter.com/reviews/the-best-usb-3-0-thumb-drive/>
thewirecutter.com
SanDisk has released a new flash drive featuring the new USB Type-C standard. SanDisk claims that the Ultra USB Type-C drive offers sequential read speeds up to 150 ...



substitute for an SSD drive for a few hours of MW recording depending on
size (Gb). I have also used the tiny Sandisk Ultra Fit flash drive
successfully.

73,

Guy Atkins
Puyallup, WA

>

>

>
> ---------- Forwarded message ----------
> From: Mark Connelly <markwa1ion@xxxxxxx>
> To: nhp@xxxxxxxx, irca@xxxxxxxxxxxxxxxx
> Cc:
> Bcc:
> Date: Wed, 8 Mar 2017 12:05:12 -0500
> Subject: Re: [IRCA] Elad FDM-S2 initial testing
> With the Perseus I had a similar experience.  Atom-based netbook (MSI
> Wind) gave me OK record / playback up to 800 kHz bandwidth but it couldn't
> cut the mustard for 1600 kHz wide captures.  Core i3 or higher: no problem.
>
> Are DXers using any netbook form-factor PC's (screen 10 to 13 inch range)
> that have i3 or better CPU's?  Seems like that's what you'd really want for
> backpacking.  Battery life in excess of 4 hours (including the receiver's
> loading) would be a plus.
>
> Of course you still have to deal with getting an antenna out there,
> hopefully a directional one.  Roll of skinny wire to stretch on the ground
> + a matching / isolation transformer might work but grounding still has to
> come into play.  Directivity would be sketchy at best.  A wire loop is
> likely better (whether cardioid or figure-of-8 pick-up).  The support
> structure for that (when trees are lacking) is going to be a bigger
> impediment to backpacking than the laptop + SDR combo.  Tuned loops, of
> course, can be quite compact but then you're essentially limited to one
> frequency at a time (live) DXing instead of wideband capture for later
> analysis.  Active whips are also compact but they can be "noise getters" if
> placed within 20 ft. or so of the laptop.  No directivity with those
> either, although a shore site produces directivity independent of the
> antenna.  Single stick pattern of my 1240 local demonstrates that:
> http://radio-locator.com/cgi-bin/patg?id=WBAS-AM&h=D
>
> (That map shows why Florida, Cuba, Puerto Rico, Venezuela, etc. bomb in
> here ... Midwest not so much.)
>
> I would always take a competent ultralight portable in the backpack as
> well, just in case something with the PC + SDR goes "kerflooey."  No sense
> to go out there and come back with nothing, especially if considerable
> flying, driving, biking, or hiking was involved.
>
> Mark Connelly, WA1ION
> South Yarmouth, MA
>
>
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