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Anybody got experience with the smaller SDR sticks?


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I'm referring to these sticks.

Way, WAY smaller than the regular sticks and from the looks of it cheaper to boot but with identical specs.

I'm considering getting one, but if anybody already has experience with one of these, I'm all ears.

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In the Realtek 2838/820 combinations I have tested ( I have three ), it doesn't seem to matter much what size they are. The only thing I might be concerned about with something that small is that heat dissipation may be problematic. The only other concern I might have is that with a smaller board like it has, there would be less room for other surface mount components ( possibly filters ), which may help in noise reduction and boosting SNR ( Signal to Noise Ratio ) on the larger units.

If you end up getting one, let us know what results you get from it.

-FuzzyBunny

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It's a mere 10 euro's and free shipping so I'll probably end up ordering one in a week or so to play with.

If you have any tests you'd like me to perform, just say which (I'm a total SDR noob ATM).

Do these sticks get that hot in your experience? Got some (rough) numbers?

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It's a mere 10 euro's and free shipping so I'll probably end up ordering one in a week or so to play with.

If you have any tests you'd like me to perform, just say which (I'm a total SDR noob ATM).

Do these sticks get that hot in your experience? Got some (rough) numbers?

My general rule of thumb is, if it is too hot to hold with your hand, or betwixt you forefinger and thumb, it is running too hot.

One way to cool it off to some extent is to get it away from your computer or desktop, possibly dangling in mid air, with a USB extension cable. The more surface area that is exposed to the air, and the more cool air (as opposed to desktop PC exhaust) the more heat it will dissipate.

Get one and see what you think.

-FuzzyBunny

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  • 2 weeks later...

I got one of these http://www.nooelec.com/store/sdr/nooelec-nesdr-nano-sdr-dvb-t-usb-stick-r820t-w-antenna-and-remote-control.html#.Uz7LXXVdU5I it works fine gets a little bit hot after awhile but I'm pretty sure there's not much frequency drift at all and that one you posted looks good I might get one for my little brother's try get them interested in sdr

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I'm referring to these sticks.

Way, WAY smaller than the regular sticks and from the looks of it cheaper to boot but with identical specs.

I'm considering getting one, but if anybody already has experience with one of these, I'm all ears.

I have one of those.... works as good or better than the NooElec R820T (NESDR Mini)... The only thing I have found is they get a lot hotter when ran 24/7...

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It arrived today. :-)

Didn't expect it so soon. Spent all of 12 but I also bought a small, flimsy tripod which I want to use as a stand for a cantenna I'll eventually build.

I couldn't even send the envelope back to china for that amount so how they even make a profit off of this is beyond me, but goooo China!

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It doesn't happen very often that I'm as impressed as I am right now.

That puny little dongle with its even punier antenna... I'm running dump1090 right now and looking at the map. I'm receiving schiphol airport over here. Hell, I'm tracking planes in Belgium and in the Netherlands as far out as Coevorden and beyond. That's in excess of 150 km (100mi) from that flimsy antenna indoors!

In the words of Phreak from the most awesome movie ever made, "Man-o-man this is gonna be good"

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That puny little dongle with its even punier antenna... I'm running dump1090 right now and looking at the map. I'm receiving schiphol airport over here. Hell, I'm tracking planes in Belgium and in the Netherlands as far out as Coevorden and beyond. That's in excess of 150 km (100mi) from that flimsy antenna indoors!

I have seen 120NM from my window. Currently getting 140NM with a DPD ADS-B antenna sitting my window. Waiting for the weather to be such that can mount it to the roof. Also have the the Pi and PoE kit so can keep the antenna cable as short as possible.

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Hi there,

I tested a lot of different DVB-T dongles and hoped that because of a smaller PCB which needs more precision to design and has shorter signal ways to maybe perform better than the classical ones on the higher frequencies, but they behave almost exactly the same as its bigger competitors with the same chip set. The frequency drift is not noticeable different ... usually within the first minute or two the oscillator reaches its long term operation window for room temperature which is not wider than the one of the bigger units. As mentioned, it gets warmer because it can not dissipate the heat so well since it is so small and the actual sensitivity seems equal to maybe very slightly better than the other R820T based units. Though the previously mentioned very valid thought about trying to reach the same goal with a smaller PCB and maybe less parts could end up in a poor design is does not apply to this case. Here they just dont waste as much space as they do in the classical R820T version where one side of the PCB is almost left empty.

If you want to modify this one for direct sampling (0-14.4MHz) or running with an external TCXO, you might be better of with the traditional big stick since there is a little more space for soldering. But apart from that I can only recommend these since they are being sold for much less than its competitors and show mainly the same great performance.

If you really want to receive above around approximately 1200MHz, you should try to get one of the rare old ones using the E4000 tuner which does not only exceed enormously in Fmax, it is also much more sensitive in most of the higher frequencies and receives up to 2300MHz, though the R820T based ones outperform the E4000 in lower frequencies in terms of signal to noise and sensitivity to intermodulation when running on a wide band outdoor antenna.

I hope this could be of help to some for decision making.

Greetings

Joe

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Fascinating opinion, not in the least because an online review that got into quite a bit of detail said that overall the R820T was better than the E4000 mainly because the R820T didn't have a band gap which the E4000 does and they claimed the R820T, while poorer at the lower frequencies, outperformed the E4000 at the higher frequencies - the exact opposite of what you're saying.

Now this online article to me is as much anecdotal evidence as your opinion here. The article didn't suggest they have multiple units with those 2 chipsets and so far neither do you so I can only assume the difference is still the luck of the draw you get with a part. At a minimum it's fair to say both have their qualities and both are very capable software radios. Since the R820T parts are cheaper, and in the case of the smaller ones cheaper still, without any really noticable drawback I expect people will just go with the R820T parts.

I had to Google TCXO - Google says "Temperature Compensated Crystal Oscillator" and Wikipedia says (in part of course) it's a component that in radios is used to stabilize frequencies. What it doesn't say is why you would want to use one other than the one on the board. Is it a coarse lump of junk or just something you can replace to make things perceptively better? Care to elaborate?

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  • 1 month later...

A TCXO device has an enclosed package (usually a metal box - see below) and has several features, but most notably uses one of a number of heaters to raise the temperature in close proximity to the crystal. Why would you do that? If the outside temperature moves around, the temperature around the crystal area will only move very slightly, if at all. A (quartz) crystal is affected by several factors, one is temperature. If you can minimize the temperature excursion of the crystal, you can minimize the frequency drift. Another type of oscillator is called an OCXO or "ovenized" compensated crystal oscillator and specifically heats the crystal to a very specific temperature (like 60C) before it is at it's operational frequency. Those oscillators have even less drift than a TCXO but draw more current to stay hot and cost WAY more than a TCXO. So, why is having a crystal frequency oscillator so stable important? When you set the frequency on the radio dial to tune in a signal of interest, if the local oscillator drifts around you will be forced to re-tune the receiver. 20140602_224953.jpg

Here is a collection of various oscillators. The ruler at the bottom is six inches long. Starting at the far left going right, is a Temperature Controlled Coaxial Resonant Oscillator {TCCRO} (~5 GHz), next to it in black is a "brick" power oscillator (949.2227979 MHz), up in front of it is a Phase Locked Dielectric Resonant Oscillator {PLDRO} (4.3 GHz), behind it, in the middle is a double oven crystal oscillator {DOCXO} (5.000000 MHz), and behind it is a Verticom YIG oscillator (11-12.7 GHz programmable tuning), next to it in the back is a Ball Efratom Rubidium Oscillator (10,000,000.000,00 Hz - yes that is 5 places past the decimal point as in tens of microHertz of accuracy). Next to it is another PLDRO (11 GHz), and all the way to the right is a Variable Frequency Oscillator {VFO} for tuning R-390 military radios (WWII). The green board is a synthesized PLL oscillator (~1550 MHz), in front of it is a high stability TCXO (100 MHz), to the right of it is a Gunn Diode Oscillator (~50 GHz), note the tiny little output aperture. The little devices scattered around in front are various discreet crystals and the little round one with two legs sticking up is a high temperature rated crystal usually fitted into the brick oscillator (the black one). The most common crystal is the one right in the middle and is used in all kinds of circuits from radios to computers to clocks. Some of the really flat devices are programmed once at the factory but can operate at wide ranges from 1 MHz to 50 MHz while other devices are very low cost and stomped out in the millions and designed to only make one frequency. There are many more designs and shapes but these were the ones floating around in my shack. - KD6W

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