Sunday, 10 December 2017

Review: Uputronics Wideband Preamp

Review: Uputronics Wideband Preamp

Also called HABamp or Habamp, a low noise radio amplifier for radio signals between 100 MHz and 4 Ghz in a metal case with bias-T or 5V external power.
Available for $45 equivalent from the manufacturer in the UK, or for $45 from in the USA (plus shipping).
Recevied review sample from the manufacturer without strings attached  - thank you. Customary legal bits here.
Testing has been carried out with multiple receivers, with a discone and frequency-specific ground plane antennas for innumerable months - for a reason.
Summary: ultimately, I must conclude that Uputronic's Wideband Preamp is the best external preamp available for radio enthusiasts for general use.
Pricey, but well worth it.

First impressions

Technical specifications from manufacturer, black and white version with instructions shipped in box:

Unit is massive, built like a tank (same case as all other Uputronics preamps), SMA female ports with nut and washer properly labeled.

Printed circuit board, gotta love the personal touch:

Large PCB and finned metal case contributes to excellent heat dissipation, metal case was only 2 degrees Celsius warmer than ambient room temperature of 19 degrees - to put values in perspective, v.3 registered 37 degrees, and a Pro Stick Plus in an metal case with thermal pads showed 42 degrees with same infrared thermometer.

Reliability was 100%. Plug in and forget. Spoke to a fellow soul who uses Uputonics gear for years, and had a blank stare whan asked about reliability: "Man, it's plugged in for I can't remember how long, never had any problems". Recent post on showed NASA uses Uputronics preamps, case closed.

Power options

Via USB Mini-A cable: same type used on external hard drives / GoPro / Garmin satnavs etc, unit can be used with any RTL-SDR or with any receiver when amplification is desired. No hassle if you have an appropriate cable, which is not supplied, nor can be ordered from Uputronics webshop, costs a few dollars on Amazon USA or similar money in any electronics shop or on eBay.

Via bias-T: also called phantom power, receiver sending power down the cable. SDRPlay RSP2 and  RSP2, v.3, Outernet E4000, Nooelec SMArtee XTR tested and preamp functioned flawlessly. Reportedly works with AirSpy and HackRF, or any other receiver with bias-T capability.
No indication that sufficient power is supplied to preamp - a LED would be nice.


Available in Uputronics webshop, mounting/lug kit costs $6, factory-fit bias-T 26V option costs $9, enclosure costs $43 (not tested).

SMA Male to SMA Male coupler / barrel adapter for $4 is a must if you don't have one to connect it to SMA receivers.


Great. Does what a preamp's supposed to do, more signal, less noise, cleaner waterfall, better SNR ratios.
No offense part: Beginners, or if you don't know how an LNA works, or if you just started discovering signals, please get a discone first, or go for a ground plane for a specific frequency. You'd be wasting your cash ordering one without antennas. Serious, here.

Versus Competitors

Uncomparable. Alternatives differ in price, features, build quality, noise figures or reception range, all are a miserable far cry when handled or used on a daily basis:

Closest I'd recommend for nearly half the price is Adam's LNA4ALL with bias-T factory mod, same chipset, proven and dependable contender:

That preamp, saying LNA4ALL here, lives at the bottom of discone for more than three years, great, Uputronics spent considerable time out in the rain, good as new.
Not a competitor, as LNA is integrated into RTL-SDR dongle, is a FlightAware Pro Stick:

Orange dongle above will be the same performance, and sometimes more, than a premium dongle and external amplifier, combined.


Amplification will always pull in more signals, so my question was whether it's a reasonable alternative versus Uputronics' own filtered ADS-B preamp (both stations are identical ModMyPi Raspberry Pi 3s running PiAware and sharing FlightAware antenna via splitter, 24 hour's data, 2% margin of error, short coax length):

Filtering added significantly more position reports and better range:

Add a FlightAware filter after the LNA (same configuration as filtered Uputronics and Pro Stick Plus):

Results are within 2% margin of error, polar plots look almost identical:

If you already have a FA filter and want a versatile wideband preamp at the same time, it seems like you won't lose that much by not going for the filtered version.

Day-to-day use personal observations

Easy. No bother. Plug in cable, or enable bias-T with v.3, power to LNA is on. Without any second thoughts, no mental pathfinding.
Reliability combined with good performance is the name of the game. More often than not, I reach for the Silver Finned Shark, as I call it by now, because I trust it to get the job done. Be it mast-mounted duty, or rediscovering weather satellites, or wanting an arbitrator for testing gear, I know the safe choice and one hand movement will be the chunky silver one when I can see, with fins on the side when I can't and go by touch.


Quality combined with excellent performance.
Alternatives might be cheaper, but none provides the mental reassurance of a well-designed product with ease of use.
Would I buy it? Yes.
If I could only have one external LNA, I'd get an Uputronics Wideband Preamp over anything else on the market. Costs a lot, but quality never goes out of fashion.

Useful accessory: Nooelec Adapter Kit

A solution for most scenarios and antenna connectors, officially called "Nooelec SMA Adapter Connectivity Kit", a plastic box with lots of shiny connectors:

Costs US$19.95  on official Nooelec website or on Amazon USA, had it in a week from the States to Europe for free as a review sample (disclaimer).

Who is this for?

Any radio lover who needs to connect different bits and pieces to radio receivers, accessories, paraphernalia and antennas, or vice versa, because the industry still haven't settled on one connector standard.

What you get

Sturdy closeable plastic box with eight compartments and fold-down latch, all 100 kg / 220 lbs of yours stood on it one-legged and didn't budge, carried box around for weeks and didn't open once. Internal dividers enable custom partitioning, no idea what purpose flimsy bit with hole serves, maybe if you're climbing a sheer wall and want to attach it to a rope? sign on top is mentally reassuring, writing what's what on each compartment might be a good idea - I had a rough idea what purpose a particular connector serves, but neighbor Jane wouldn't have a clue.
All connectors end up in SMA male termination, which is the most common on quality SDR gear, so it's possible to connect any equipment, such as Nooelec SMArt / v.3 / SDRPlay RSP / AirSpy / whatever with SMA female sticking out.

Female N-connector: Chunky pro level equipment uses N-connectors, like transmitters and antennas in the kiloWatt range.

Female F-connector: Standard for TV in the USA, satellite and cable TV and internet modems in Europe, widespread around the world.

Great fan of this standard as easiest to assemble at home, plugs are cheap as chips at any electrical shop.

SO 239: Relic from WW2, oldtimers with tabletop HF transceivers or CB equipment might need it. Not using it at the moment, love the fact it's included, because any CB magnetic mount (or similar gear found for cheap) could be easily utilized.

BNC adapter: also known as bajonet mount, push and twist, for instance, use with scanner antennas (in image below).

For an at-home setup, CCTV T-junctions and coax notches based on BNC connectors work extremely well as a poor man's bandpass filter.

MCX: SMA Male to MCX Female, so if you got an old antenna mount, it can be used with the latest gear:

PAL: TV standard in Europe and in many parts of the world - use store-bought antennas easily.

PAL is extremely easy to work with due to size and no-brainer one-hand push-in movement.
RP SMA: RP means Reverse Polarity, easier to explain with an image:

Reverse Polarity often catches out beginners as they wish to use WiFi antennas with dongles without any success - inserting a 4mm coax center inbetween is a solution, but the proper adapter will be less hassle:

Male SMA barrel: Standard to connect any SMA to any other SMA gear, priceless when you want two otherwise useless doorstops to work in harmony.


Tried all connectors with multiple antennas / LNAs / receivers and all functioned flawlessly. Personal sidenote: I use Nooelec connectors for over two years and not one malfunction ever, so got no doubts this kit will serve me into 2020 easily.

Barrel or pigtail?

Barrel adapters, like the contents of this kit, have less points of failure and less signal loss due to no coax cable used. Pigtails are more flexible, easier to screw on / off, but cost more.
Depends on what you wanna do: for a fixed setup when components are not moved around, like ADS-B testing, I prefer barrel connectors. For on-the-road use, pigtails are clear winners due to less stress on connectors and PCB mounting points.

Competitors and value for money offers a 6-piece set for $15 without a box or quite a few alternatives, haven't tested them, so can't comment. Seriously doubt that these connectors / adapters are markedly different from other offerings on the market, try searching eBay for "SMA adapter kit", results will look identical with prices hovering around the 1.50- 3 dollar mark per piece with shipping from China, or six to eight piece kits for around 10-15 USD can be had.
8 adapters in a plastic box for $20 from a trusted brand is reasonable.
Look into what you need, examine photos above to identify you dongle / antennas / gear, think about future prospects.

Would I spend my own money on this?

Yes. Flexibility is the name of the game, especially if you've amassed an antenna connection, and it's eventually cheaper and easier to have one box that enables otherwise useless bits and pieces to function.

Wednesday, 6 December 2017

Review: RTL-SDR Blog Multipurpose Dipole Antenna Kit

What is this? Four antennas, two mounts, one antenna holder with cable and one more extension cable. Costs $10 on its own, or $25 with v.3 dongle. Was at my doorstep in two weeks from China to Ireland, observations below are based on two months' of constant use.
Please read the official how-to guide for more information, this post is a practical look at what you get and what you can do with it.

In the envelope

Bubble wrap surrounding a cardboard box. And the box is full:

Sang the song for the dongle already, so I'll concentrate on the antenna pack:
- bendable antenna mount / tripod with camera connector screw,
- suction cup with camera connector screw,
 - mount for antennas with camera connector screw,
- two large antennas,
- two small antennas,
- 3m / 10 ft extension coax.

Bendable tripod

About hand-sized including top screw, legs are 5" / 13 cm, similar products are also called gorilla pods / bendy tripods, 'cause legs are flexible to wrap around anything a primate can grip.

Built-in ballhead with lock-down screw:

Top screw is industry-standard mount for cameras, held pocket digital camera (245g / 8 5/8 oz) without effort, hopeless with heavy Nikon body, rock solid with antenna base. Even a thrift store tripod features the same screw:

Antenna base screws onto mount or suction cup (later, read on), so if you've got a more substantial tripod for photography e.g. a Manfrotto with a ball head, an earthquake-proof setup can be done in no time.
Similar tripods can be bought on eBay for $2-4 dollars if you like the concept:

Suction cup mount

Comes in several pieces, quite confident that if you've completed any LEGO aimed for 6-9 year old kids without shrieks you'll manage, end up with this:

Hands up if you carry isopropyl alcohol or window cleaner around, which is the official procedure, preparations are the same as with any other suction cup mount used for smartphones / GPS / tablets etc: clean surface with any cloth at hand or on you, spit on / lick finger, then distribute saliva evenly on circle, push on flat surface, lock down by pressing lever down, check for firm hold.
Was holding casserole pot attached to mirror, weight unknown (digital scale said "err") but bloody heavy, the two-person dinner / straining to lift out from oven variety.
Functioned on the car, either on windowpanes or on the roof, on the trunk / boot lid, and on RV, two larger antennas fully extended at 70 mhp / 120 kmph for 800 km / 500 miles did not come off.

Antenna mount

Holds four supplied antennas, obviously two at a time, screws onto two supplied mounts detailed above. Antennas and angles can be adjusted with screw, no screwdriver supplied:

With two smaller antennas:

Not for outdoor use as per official recommendation, Hurricane Ophelia hit where I live with sustained 60-80 mph winds and copious rain to make matters worse, mount was outdoors during that period on comparative ADS-B duty without any illness.
Sidenote: manufacturers must warn against outdoor use, 'cause if your house burns down, user collects an STD whilst looking at an outside setup or what have you, insurance companies can blame any outdoor antenna as the culprit. previous mag mounts, Nooelec mounts with innumerable antennas, FlightAware ADS-B antenna and quite a few homemade aerials never gave me any trouble.
Not for outdoor use, again: here's what mount looked like after living outside in wet, rainy, utterly miserable conditions a.k.a. Irish winter for two months:

De-assembled mount:

For outdoor use, a barrier sealant (wax / fat / WD40 / anything acting as a barrier against water) is a must.

Four supplied antennas

Two small and two large, covering shortwave to Gigahertz range.
Fantastic feature of extendable antennas that users must understand frequency / antenna length relationship, posted specific frequencies of common interest:

A dipole antenna, by its very nature, will be useful around the desired frequency - two shorter antennas fully collapsed (1030 MHz as above) performed well when pitted against a dedicated $45 ADS-B FlightAware antenna: 20,705 vs 11,386 positions reported over 21 hour period:

Because antennas are adjustable, fine-tuning for the desired frequency is easy-peasy and recommended for best performance.

Coax cables

Short and thin attached to base, there's an extra 10 foot / 3m extension just in case in the box. Best you get with any RTL-SDR dongle, generics' arm-length is a joke in comparison.

Antenna location is everything, take home one lesson from this post: antenna location is everything. Having cable at hand will let you place antenna in an ideal location: outdoors, away from electronics, as high as possible.

What will the neighbor say?

Nothing. People who don't know, nor care about antennas have seen or painstakingly adjusted bunny ears antennas for televisions, therefore those lovely peeking senior citizens won't move the curtain unnecessarily. Looks like a TV antenna, here's what people are accustomed to:

... but it's not a bunny ears, as I found out. For best performance, orient legs vertical / up and down, once problem sources got used to the sight of the antenna.
You'll be able to hold a painful conversation with Mary when she deliberately cuts her roses waiting for a chat without daydreaming about a cleaver, a feat you can't repeat with a discone. On the other hand, a TV License inspector will have yee (SW Ireland pronunciation of "you") over the barrel in no time if you live with stupid rules, say here or in the UK.


None. No other manufacturer offers an equivalent antenna kit; especially not at $10. A single SMA connector telescopic costs 5-8 USD on eBay, and lest you go on any ham radio website, be prepared to pay over $20 for one antenna. A pro ADS-B antenna or discone costs around $50 at the bottom end, near $70-100 for midrange, so $10 is peanuts without monkeys.
Nooelec's SMArt family antenna kit (comes standard with regular SMArt, XTR and XTRTee) is better quality overall but without the flexibility and adjustability, generic's one puny antenna simply can not compete with what you get.

Worth the money?

Count together: bendy pod $3, suction cup $3, four telescopic antennas $1 each, 3m / 10 ft coax coax is around, say $3, toroid $1, and prices are low estimates.
Without hesitation. Antenna kit is sold out now, so I ordered the full bundle after handling the review sample, as $25 is a no-brainer for the antenna kit and dongle.

Sunday, 3 December 2017 antenna kit: Orientation Matters

A lot. Official recommendation is to install antenna vertical (up-and-down), as a real man, didn't read the manual, then posted results in a recent ADS-B comparison.
Mea culpa, I was wrong, as an eagle-eyed reader pointed out:

"Orienting dipoles goes back to the signal polarization, horizontal vs vertical. It should match otherwise you'll get losses. But the way you've oriented it makes it vertical, but more like a whip. So there should be some improvement by using it in the correct orientation. TV signals are usually strong and so the bunny ears can withstand being in the wrong or random orientations."

Fair enough, so onto ADS-B testing, got an antenna kit from for review and ordered one within minutes as it's well worth the money, then some ended up with two identical kits:

Back end is two ModMy Pi 3 Raspberries, so only variable is antenna used:

Then my jaw dropped, bunny ears configuration results:

Vertical dipole results:

No math required, more than 2x performance. Where's a stone I can hide under?

Polar plots

First of December, 21,033 Totals on vertical orientation, geographical coverage:

Bunny ears with 9,563 Totals on the same day, geographical coverage:


"RTL-SDR Blog Multipurpose Dipole Antenna Kit" works, 144 nm max range in an unamped, stock setup is simply astonishing at my location.
Would, and do recommend to grab as many as you can from the manufacturer, but others have also seen that sliced bread is better than a loaf, therefore it's sold out.

Behind the Scenes: Photography and Building a Lightbox

RTL-SDR dongles, preamps and tools of trade are small. Here's what I came up with for little money, and why it works for me.
Tips are also applicable to small product photography, and so on.

Build a lightbox

Using one, two or three lamps results in shadows, which take aeons to remove in Photoshop, and I simply have no time. Enter a lightbox, which is a cardboard box with lamps for optimal illumination, watch Youtube videos here, here, and here for inspiration just like I did, common trait is having a box and lights on the side, the more the better, first result:

Product image wasn't bad:

1. Lights shines into camera and my eyes, and looking into thousands of lumen is not fun.
2. No reflective surfaces, less light reaching object.
3. Unacceptable shadows on the left hand side.

Improved lightbox

All light sources covered from camera, easier on me eyes:

Same with less shadows:

Being able to look at an object is worth more than more light and white speckles swimming in my vision.

Lumens and color temperature

Lumens: how much light emitted by bulb, written on packaging. Also given as W at the bottom (how much power bulb uses). The more, the better, 50 W combined from LED and fluorescents is more than enough, or 4-5000 lumens light output.

Light sources must be distributed for an even coverage and to get no shadows. I put two on top, two in the top left corner, two at bottom corners. Connections are easy-peasy, cut a hole, screw in bulb.

Sidenote: Some might say cardboard, paper and a heat source is disaster, and I totally agree. Do not use incandescent lights, floodlights or HID lights, if in doubt, test: turn off = touch with hand then hot, auch = don't use. Fluorescent and LED give more light and cooler to touch.
Color temperature: that's the number before the K on the bulb above, LED and fluorescent lights are used interchangeably, not on purpose, simply I could buy them for cheap. Most cameras are great sensing color temperature, if really skewed, can adjust in Photoshop:

Note that Auto Color (Ctrl + Shift + B) does a good job, but all image adjustments in PS should be done as adjustment layers like above. That said, for lesser images I do Ruler Tool, then Crop (C), then Ctrl - Shift - L, then B, be done.


Sony DSC HX9V, a compact point-and-shoot. Images below are straight from camera, no Photoshop.

Automatic mode does not do the job, that's the green setting, result is dismal:

Program mode, multi-AF and multi-metering with flash:

Usable, small shadow on right for depth perception, would add +25 brightness after cropping.
Smartphones: work for on-the-go images, and great for family photos, but ultimate quality is nowhere near a dedicated camera, I use a Samsung J5 2016. Shoe from a cobbler.


Don't. It's better and ultimately less time to set up a lightbox, even when you play with camera for two days to find the best settings, than to spend hours in Photoshop adjusting sliders down the line, plus it's easier to get it right the first time, taking care in - great image out, 5 minutes with an image (which is more like 30 minutes once the rush for perfection overcomes you) when a post contains 20+ images is time wasted.
Do. Before a post with images goes online, I check images on a 49" screen to find any faults, invariably, there's something to improve. Deciding what needs to be completed and knowing when I gotta wake up for work leads to compromises.

Connectors and macro photography

Must crop and do post post-processing, before and after:

Ensure background is evenly illuminated, so magic wand (W) will work efficiently. Looking closely, you'll see that grooves are not cleaned on this F-connector, Eraser tool (E) is my least favorite command.
I tend to take multiple images then choose the best one, as hand shaking, distance to subject and lighting differences will make or break the final image.