Tag Archives: upconverter

The “MINNIE”: RTL-SDR and DIY Upconverter in the same enclosure.

By Nick G0CWA

Hi this is my latest design for a RTL-SDR communications receiver. The set amounts to little more than a switchable receive up converter. Although designed for the Realtek RTL2832U Chipset + Elonics E4000 tuner, it will work with any of the other compatible tuners. I would personally recommend SDR# as the control package for the dongle. http://sdrsharp.com/

The frequencies from DC to ~1.7GHz are covered in two ranges: High range ~60MHz to 1.7GHz (depending on tuner chip) with the normal gap around 1.1GHz And Low range DC to 60MHz.

The main aim was to build a version of my designs to comfortably fit into a Lap top bag and be fully portable and powered from the PC USB port. The completed unit including a dongle fits into a small die-cast instrument case measuring only 55x25x125mm. To keep the circuitry size to a minimum I have not included any extras e.g. pre-amp or antenna switching etc.

SDR Receiver using a tv dongle rear view

There is nothing clever or particularly original in the design with one exception the use of a 125MHz conversion oscillator so avoiding the VHF broadcast band on the output and reducing any sensitivity issues. The 5V supply is taken off the dongles USB connector by opening up the dongle case, carefully, and soldering a fine insulated wire to the appropriate USB connector pin taking this out through a small opening cut in the side of the dongle case.

SDR Receiver using a tv dongle inside

Follow my track layout and use top quality miniature co-ax for maximum sensitivity I used silver plated. Do NOT use single strand wire for any RF signals as these dongles are very sensitive to mis-matches and unless you are very lucky will shut down and work poorly, if at all.

SDR Receiver using a tv dongle schematic

SDR Schematic (Larger View)

You may notice that D1, D2, C11 and C12 do not appear on the PCB top they are actually soldered on the underside of the board to save space. There are also two wire links on the top of the PCB to add.

The RF input to the dongle is via a connector shown in the “real world” PCB layout diagram. This connector was “scavenged” from a cheap plastic bodied co-ax plug which is soldered to the PCB in a small slot. TAKE NOTE the connector is soldered on both sides bridging the two earth pads to complete the ground track to both sides of the PCB; the centre pin is connected via a small piece of copper wire to the PCB.

The only problem I had was when switching between the receive bands sometimes the dongle would lock up, this was due to the current demands of the relays and smoothing caps I managed to “cure this problem” by reducing the values of C11 and C12 anything above 100 nF should be ok.

The actual PCB dimensions and cut-outs suited both my box and gave sufficient clearance for the dongle, antenna socket and switch. Adjust these to suit your case etc.

The coils are all 6.5 turns of ~1mm diameter copper wire 0.25 inch diameter by 0.4 inch long, the relays are both NEC/TOKIN UB2-5NE 5V Coil DP Ch-over types although any similar equivalent ones may be used. The regulator is an LM1117T 3.3V unit. The crystal oscillator is a 3.3V 125MHz crystal oscillator module, any oscillator module frequency above 60MHz can be used but I can’t guarantee the receivers performance or immunity to de-sentisation/interference from the VHF broadcast bands.

For any further information about operation and performance check my MK2 design write up also on this site.

Enjoy this design hope you find it of use.

The Radio board and QRZ forums With any questions, please only contact me via these routes if you have any questions, I can’t guarantee to reply otherwise as I can’t see every reference to my sets. Enjoy the design 73 for now Nick G0CWA

Take a look at Mike’s RTL SDR website. This is quite a popular project!

Please note I do not supply kits, parts, PCB’s or build boards for my projects but am more than willing to help talk you through a build or fault finding via my normal contact methods, or even SKYPE if required for direct contact.

Round-Up of RTLSDR Upconverter Choices

I’m trying to catalog all the different HF upconverters on the market for the RTLSDR. The RTLSDR stack, a combination of radio software such as GNUradio or SDR# with a Realtek RTL2383 + Elonics E4000-based DVB-T tuner using a modified driver, is getting to be very popular among amateur radio enthusiasts because it’s cheap and highly versatile to allow you to receive on a very wide frequency range. Unfortunately, the chip has some limitations – that wide range only goes from about 50-2200MHz with most in the 64-1700MHz range. That’s well above the HF bands where many ham radio operators and shortwave or AM stations are found.

Fortunately, the marketplace has taken care of that limitation, and quite a few choices for an HF converter / up-converter are now available which use a mixer and crystal oscillator to add around 100MHz to the incoming signals, shifting them into the tuner’s frequency range. There are several choices out there, including pre-built boards, partially built kits, and plans depending on your skill level and interest. An assembled board or a partially assembled kit will probably set you back about $50-100; if you’re savvy you can probably make it for $10-20 in parts – if you don’t mind winding your own coils. Your mileage may vary.

So, getting to it, these are your choices arranged with built boards near the top, partially built boards and kits near the middle, and plans and project logs near the end.

If you have any others I’ve missed, send me an e-mail! 

1. There’s a new Ham It Up v1.2 HF upconverter for software defined radio produced by Opendous which has a large amount of documentation including layouts, and can be purchased mostly-assembled for only about $50. v1.2 makes some small improvements, including a 125MHz crystal instead of a 100MHz crystal to ensure there’s no interference from the U.S. FM Broadcast Band. It also features an input switch and an optional hardware noise source is an interesting, if possibly seldom used, feature. Ham Radio Science has a rather extensive review of the original revision and were pretty happy with it.

2. CT1FFU v5  HF converter is a brand new iteration of the long-standing design which was originally one of the first released. This model features an improved smaller PCB size, improved filtering and am improved ring mixer, and phantom power to eliminate a power cable when attached to certain compatible RTLSDR receivers. The LO is still 65.520MHz or 106.250MHz which might interfere with an FM Broadcast band in some countries, such as the U.S., but there is some filtering incorporated to eliminate that. The price is reduced to 55 Euro shipped worldwide with tracking.

3. Marty KN0CK has developed an incredible upconverter which fits inside the tuner dongle’s enclosure using all 0402 SMD parts. It’s a complete stack, including the RTLSDR tuner and hand-assembled precision converter with a SA612-based mixer and Mini-Circuits MAR-8+ amplifier and 120MHz oscillator. Very powerful, great at picking out weak signals, and requires no external hardware or cabling everywhere – just hook up an antenna and go. Available for $100 US plus shipping (U.S. and International shipping available), this is a addition to your ham shack. Buy it over at Easy-Kits. Bare boards are also available for incorporating into your own project.


4. I’ve been using CT1FFU’s v3.1 dongleGerman retailer Wimo sells completed kits, which have been in stock even when CT1FFU’s own kits have sold out. A no frills HF up-converter, mine came assembled except for the SMA connectors. It’s one of the early generation upconverters but still offers solid performance. V3.1 uses a 106.250MHz IF.

Wimo also sells the FunCube dongle, if you don’t already have an SDR.

5. JA7TDO has produced the Soft66RTL, including an RTL2383u+R820T and an HF converter with a 50MHz local oscillator frequency in what looks to be a nice, 3D-printed case capable of receiving up to 30MHz, or 50MHz and above bypassing the converter.


6. JaniLab has started selling a derivative of the CT1FFU v2.0 on eBay for a bit lower of a price than some of the others. The older revisions work well, although with some more leakage than subsequent designs, and don’t have quite as fancy filtering or switching features.

Janilab actually offers several. There’s both this one with the DBM mixer, above, and another CT1FFU v2.1 derivative with an SPL mixer.

7. Janilab also sells another DBM mixer-based converter, with an antenna switch to bypass the conversion.

8. And if that wasn’t enough, they even rolled their own board and put an RTLSDR and an converter on the same PCB, with an integral antenna switch. This is incredible. Not cheap, though.

9. If you’re looking for a more rugged commercial solution, High Sierra Microwave has an upconverter (FCD-1-55-UC) with a 133MHz IF frequency and BNC terminals with an integral amplifier. I’m a fan of converters whose LO frequency shifts the entire HF range above the FM broadcast band in general and the shielded enclosure will definitely cut down on noise. Looks like it’s suitable for mounting outside at your antenna’s feed point, and it also looks like you’re going to pay for those features. If anyone owns one and wants to share their experience with it, or if High Sierra Microwave wants to send me one to evaluate (*wink wink*) I’d

If you’re more ambitious, you can roll your own up-converter from parts. FAR Circuits appears to have manufactured PCBs for sale for many QST projects, including one upconverter. I’ve only recently discovered this site and there seems to be a lot of good stuff.

10. W9RAN developed a RANverter kit which was featured in the January 2013 issue of QST magazine, using a 125MHz local oscillator. It’s gotten a lot of great buzz on the Internet and offers good performance and even a little bit of conversion gain through the mixer. Unfortunately, he appears to no longer be offering it for sale. I did manage to get a set of boards and will be offering the W9RAN precision converter through Easy-Kits.com before the end of the year!

11. If you’re comfortable speaking  Dutch, or just with Google Translate, you can buy the Kit RF Converter for RTL SDR Sticks DC – 65 MHz. Unlike most other models, this one HF up-converter takes a BNC 50 Ohm antenna input and has an SMA 50 Ohm output with a 100 MHz oscillator frequency and built-in protection. This one also looks like a great starter kit with through-hole components and large coils and looks easy to build. You can also purchase the completed assembled kit in an enclosure, which also includes a power cable and SMA-MCX adapter cable. Looks interesting.

12. Kalle over at DGK Electronics has a great looking compact 100MHz HF converter designed to fit inside of a pre-made RF shielding box. It uses the ADE-1 mixer and an ASEM oscillator. It has some of the most complex filters and great filtering on the incoming power line, it probably performs very well. He describes the filters on his page, and there’s also a full schematic available. There’s a photo of a pile of boards, and he says there’s still some available, one might be left! DGK Electronics

13. David Forsman, WA7JHZ, sent me a photo and plans of his 125MHz HF up-converter with a diode limiter, attenuator, and amplifier all in one from plans featured in Jan ’13 QST magazine. Click through there to the article for a schematic and explanation for more details and a full schematic. Thanks, David!

14. Matt Dawson GW0VNR has a very interesting HF converter using more discrete parts than some of the other ones I’ve seen. It uses hand-wound transformers, an actual discrete diode mixer, and a Saronix oscillator running at 106.25 MHz. It uses a total of 23 parts and looks like it would be pretty easy to build. He doesn’t have any photos of the completed board, but does have a full schematic, overlay, transfer mask and Gerber files for the PCB. I’m pretty sure I have all the parts to build this one in my box as well. It looks interesting and simple. Check it out.

15. Radio amateur Paulino Sato has posted schematics and specifications for using the TA7358AP FM Front-End as an HF up-converter you can build yourself, using small coils wound on your own forms. It’s a bit of a commitment, but only has about 40 parts. The instructions are in PDF format. Download from me directly or the original is available on DropBox. The PDF contains PCB masks and silk screen layouts and a full schematic.

16. Over in the UK at the George Smart Wiki, we see homebrew plans by M1GEO using hand-wound coils with an SBL-1 mixer and 100MHz crystal oscillator. It has around 20 parts to assemble. These coils look like they could be hand wound on a dowel coil form, and the crystal and mixer are very large parts, so you could probably build this on perfboard without any trouble.

17. Bryce Salmi KB1LQC built a very rugged-looking clone of George Smart’s above with some modfiications dead bug style.

18. Romanian amateur Alexandru YO2LDK built a simple HF upconverter circuit using an NE602. This has an amplifier, limiter, regulated supply and 100MHz frequency like several of the ones pictured, but the circuit itself looks quite different. The amplifier stage is ahead of the limiter, which looks like this one is offering a constant gain versus the adjustable gain some of the others have offered. It looks like this one has more tunable components, which means a little more work to dial it in. I didn’t see any photos of the completed product.

19. Nick G0CWA built an interesting switchable upconverter design, complete with instructions and board layout PDFs.

20. Japanese amateur JA2GQP build a rather minimalist upconverter with only a 19 components offering a +50MHz frequency shift. He’s included a schematic and PCB mask for you to build your own very easily!

There are plenty of options to build or buy for getting HF signals into the VHF range for your RTLSDR. With these choices, there are plenty of options for getting HF signals into the VHF ranges for use with the RTLSDR. It’s not difficult to modify these plans for even higher fidelity and accuracy, such as by increasing filtering on the power lines, building a shielded enclosure, improved antenna systems, and more.

I’ve been using my v3.1 Converter from Wimo for a few months, and have been very happy with its performance so far – there’s little noise and leakage, and I use it to pull in shortwave broadcasts from all over the world including the BBC, China, Cuba, Japan, Russia and more from my home in Seattle with only an 80″ long wire and a string of adapters – I highly recommend that model, or any of the models in this family, for great performance. I’m looking forward to trying out some of these other ones.

If you have a design you’d like to see featured here, let me know!

Edit 12/1/2013: Added JA2GQP’s minimalist SDR upconverter.

Edit 10/29/2012: NooElec offers “Ham It Up v1.0″ upconverter which looks to be based on a different design, and seems very high quality. Check it out! 

Edit 2/2/2013: Better info about the Opendous Upconverter, KB1LQC’s DIY Upconverter, and WA7JHZ’s upconverter.

Edit 2/3/2013:Added 9A4QV HF Upconverter SDR UP-100, G0CWA 2012 upconverter, YO2LDK upconverter.

Edit 2/13/2013: Added Vandijken Elektronica upconverter and W9RAN RANVerter 2.0.

Edit 2/19/2013: Added KN0CK SMD HF Upconverter

Edit 2/25/2013: Added Matt GW0VNR’s Upconverter and the DGK Electronics HF Converter.

Edit 4/13/2013: Added JaniLab converters, High Sierra Microwave converter.

Edit 4/25/2013: Informed 9A4QV Out of Stock – Thanks Adam!

Edit 5/14/2013: Ham It Up v1.0 > v1.2, Now Ships with 125MHz Crystal

Edit 8/13/2013: CT1FFU v5 replaces CT1FFU v3.1, and some copy-editing!

Edit 9/2/2013: Updated to reflect availability of some items.

Edit 10/21/2013: Added Soft66RTL

Extracted from: blog.kf7lze.net

LNA4HF: DVB-T SDR Upconverter gadget

After we stop to make and distribute the Upconverter gadget UP-100 for the DVB-T SDR dongle we start to receive the e-mails asking to help to improve the performance of the present Upconverters that can be found on the market that are not our products. We decide to design this gadget to help all this guys suffering the weak reception on the HF using various upconverters.

So here it is, LNA for HF. This small gadget can improve your reception by amplifying the HF frequencies in range from 150 kHz – 30 MHz by 19 dB. Up to now we make a couple of such amplifiers (without LP filter) on request but due to increased interest we decide to improve the already good design. The same LNA board accommodate now also the 5 pole low pass 30 MHz cutoff filter at the input together with the active MMIC device, all on the small PCB measuring only 1″ square (25x25mm).
The board can be powered from 6-12 VDC but there is possibility to power the board also with the 5 VDC from the already existing 5 V that you have on the upconverter. The consumption is only 19mA which should not create any problems for any regulator you have installed there. SMA connectors on the input and the output became a “standard” with this gadgets so only one extra SMA male/male jumper cable is required or SMA male/male adapter and that’s it.
This is just a working prototype made on the LNA4ALL PCB to check the performance of the filter and the amplifier. This is not a finished product. So I need your opinion and according to the interest we can produce a batch of the amplifiers. The target price is 20 Euro for the assembled and tested LNA together with the SMA connectors on board. There is an option to have also the LNA for the HF without the low pass filter at the input for all those who wish to use the same LNA also higher up to 1 GHz. The gain of the LNA without filters is around 18-20dB up to 1GHz and NF up to 2.5dB.
This is how you should connect the LNA4HF together with the existing Upconverter and DVB-T dongle.
I have comments opened for you to see how many interest there will be for a product where you can state your ideas about the price, filters, power supply etc. If we receive the interest for at least 50 LNA4HF we will make a batch of 100-150 pcs. The quality of the product should be the same as the LNA4ALL or UP-100 and up to now we did not have complains on the quality and design of the PCB.
Of course, we plan to offer just a PCB for the guys wish to design their own LNA with the MMIC they like and the filter they want. The same board can accommodate several MMIC types.
If you need the LNA4HF let us know, the comments are open for discussion.