Tagged: HF

Softrock Ensemble II vs the RTL-SDR + Upconverter on Shortwave

Over on YouTube user mutezone has posted a video comparing the RTL-SDR with upconverter against a Softrock Ensemble II software defined radio. The Softrock Ensemble II is an SDR dedicated to the HF frequencies and is thus expected to have better performance for that purpose. Mutezone writes

A performance between the Softrock Ensemble II vs the RTL-SDR (R820T) on shortwave. Here we are trying to see which one is best at receiving AM broadcasters. Both SDRs were using the same longwire antenna connected to an ATU (Antenna Tuning Unit).

Although I know this comparison is somewhat unfair, since the RTL-SDR is not meant for shortwave & the Softrock is, it is to show that there is a difference in performance, even though the RTL-SDR has a much wider frequency range & cannot be beaten when it comes to value for money. My opinion is that if you want an SDR that should deliver on HF / Shortwave performance, then go for a dedicated one like the Softrock, Afedri, SDR-IQ or any others that do the same job on the market. Even when using a decent HF Upconverter, the RTL-SDR will still not match the performance of more upmarket HF SDRs.

Direct Sampling Mode with No Hardware Modifcations

Update: There is now a newer driver that allows HF tuning without hardware mods via a different mechanism. The new mod seems to work better than this one. Read about it at https://www.rtl-sdr.com/new-experimental-r820t-rtl-sdr-driver-tunes-13-mhz-lower/.

Over on the Reddit RTL-SDR forums user Jengal has posted a modified RTLSDR.dll dll file for SDR# which allows the direct sampling mode to be used on the R820T without the need for any hardware modifications. The modified dll is compiled from keenerds experimental branch of the RTL-SDR driver, which uses code for the no hardware mod written by tejeez. The no hardware direct sampling code was inspired by Anonofish’s discovery where he found that the E4000 based RTL-SDR could tune to AM radio without the need for the direct sampling mod (though this appears to be now patched in the newer rtlsdr drivers).

The direct sampling mod is a hardware modification to the RTL-SDR which allows it to receive HF frequencies between 0-14.4 MHz without the need for an upconverter. It works by connecting an antenna directly to the RTL2832U chip, thus bypassing the tuner. Teejez’s modification tells the RTL-SDR to bypass the tuner in software, allowing antennas to be connected to the normal antenna port. HF reception with the experimental driver is very poor in comparison to the direct sampling hardware mod or an upconverter, but even so Jengal was able to receive AM Radio, an SSB ham radio signal and an HF weather report with a simple longwire antenna.

To use the modified dll, simply download it from this link, rename it to rtlsdr.dll, and replace the original rtlsdr.dll in the SDR# folder. Then connect an HF antenna to the normal antenna port and in SDR# tune to a frequency between 0-14.4 MHz. Next turn ON the RTL AGC option in the configure menu. Jengal replaced the function of the RTL AGC option with the direct sampling mod. He found that best reception occurred when he set the gain to 48 dB.

No Hardware Mod Direct Sampling in SDR# Receiving AM Radio
No Hardware Mod Direct Sampling in SDR# Receiving AM Radio

RTL-SDR + Upconverter vs. Portable Shortwave Receiver

Akos from the SDR for Mariners blog has put together an article doing a comparison between the RTL-SDR + ham-it-up upconverter and a Grunding G8 Traveler II Digital conventional portable hardware shortwave radio.

His results show that the RTL-SDR and portable receiver are comparable in terms of performance, with a slight edge to the RTL-SDR. He adds that software tweaks available in SDR# can improve the voice quality for the RTL-SDR. However his final recommendation for general shortwave listening is that the portable is still the better option due to it’s ease of use.

RTL-SDR + Upconverter vs. Portable Shortwave Radio
RTL-SDR + Upconverter vs. Portable Shortwave Radio

KN0CK and KF7LZE Custom HF RTL-SDR Receiver Revision 5

Update: KN0CKs products are now available at http://www.kn0ck.com/HF_SDR/.

Previously on this blog we’ve seen KN0CK release his custom modified RTL-SDR tuners which have built in upconverters for accessing the HF bands. Revision 5 of the KN0CK receiver is now almost ready for sale, and will be sold over at KF7LZE’s webstore Easy-Kits.com.

Revision 5 promises to be lower priced as it will run using the direct sampling mod instead of using an upconverter which would require more components. It will also use a Mini-Circuits MAR 8 wideband amplifier to improve weak signal performance.

Kn0CK and KF7LZE RTL-SDR HF Receiver Rev. 5
Kn0CK and KF7LZE RTL-SDR HF Receiver Rev. 5

SiDRadio: RTL-SDR Kit including Preselector & Upconverter

The Australian Silicon Chip magazine has written an article about a kitset for a 100KHz to 2 GHz receiver based on the RTL-SDR that they are selling. Note, you will need to pay in order to be able to read the entire article.

Completing the kit gives you a radio with two antenna inputs, a 5-band preselector, an RF amplifier and an upconverter for the HF bands.

SiDRADIO Overview
SiDRADIO Overview
SiDRADIO
SiDRADIO

 

Upconverter Comparison: Nooelec Ham it Up vs SDR Up 100

A few weeks ago Akos from the SDR for Mariners blog did a review of the SDR Up 100 Upconverter, and he promised to compare it with the Nooelec Ham-it-up Upconverter when it arrived. He has now done the comparison, and written about it on his blog.

For each test he used a gain of 0dB and the same 20 foot random wire antenna. Interestingly, his results show that the SDR Up 100 significantly outperforms the Ham-it-up upconverter. We believe that this may be as the SDR Up 100 has an LNA built into it whereas the Ham it up does not.

Update: Akos has now included comparisons with various RTL gain settings.

upconverterCompare
SDR Up 100 vs Ham It Up
Nooelec vs Up 100 comparison
Comparison Images

Review of the SDR UP-100 Upconverter

Akos from the SDR for mariners blog has written a review on the SDR UP-100 upconverter. The SDR UP-100 is a 50 USD upconverter for the RTL-SDR and similar software defined radios which is made by the same person behind the LNA4ALL low noise amplifier. Upconverters allow the RTL-SDR to receive between 0 and 30 MHz, where ham radio, military, marine and many other interesting signals exist.

In the review Akos tests the SDR UP-100 with a 6 meter random wire antenna and an RTL-SDR. His results show that the upconverter works well as expected. In the future he hopes to compare the SDR UP-100 with the Ham-It-Up Upconverter from Nooelec.

SDR UP-100

Version 5.0 of the CT1FFU Upconverter Now Available

Version 5 of the popular CT1FFU HF upconverter which is often used with the RTL-SDR and Funcube software defined radios has been made available for sale. A ready built and tested version 5 CT1FFU upconverter will cost you 55 Euros. See the circuit diagram and technical specs in this pdf file.

The upgrades include

– Smaller size PCB

– 4 new holes for screwing PCB

– MiniUSB connector

– 2 led 5V indication USB/ Phantom Power

– It runs with phantom power directly from Fun Cube Dongle’s SMA cable

– USB power for generic RTL TV dongle sticks

– Separeted antenna inputs HF/6m and VHF/UHF

– Automatic internal relay antenna switch: HF or Bypass VHF and UP

– WFM broadcast filter avoiding saturation of SDR front-end

– LED indication for converter running

– DBM diode ring mixer 7 dBm: This ensures exellent HF reception performance

– LO on 106.250 Mhz or 65.520Mhz: This avoids interference from WFM radios

– Tests made by hams worldwide reveal exceptional clean reception on HF

– Technical assistance after selling

– Either ready built and tested or as KIT easy to build by yourself

– Worldwide shipping and tracking is included in advertised price

– You can now choose the LO freq: 106.250Mhz or 65.520Mhz models