Klaus & Lita

SDR with Active Antennas for HF

A couple of weeks ago I started to gather my first experiences with software defined radios (SDR) and active antennas. I started with low investment, using the RTL SDR dongle, but I quickly realized that using the direct sampling mode for HF is not an ideal solution and added the Spyverter HF up-converter.

For my first trials I used a Mini Whip from RA0SMS as antenna, but the results were quite disappointing.

Finally, I ended up with an active loop antenna (see featured image), using the Cross-country Wireless Loop antenna pre-amplifier (10 kHz to 30 MHz version). The pre-amplifier is powered with 13.8 V via a bias-tee. Common mode chokes on the antenna line and all power lines helped to reduce noise, especially on the low bands. This is final hardware setup setup:

The setup is now running 24/7 on a Raspberry Pi 3B+ using GQRX and WSJT-X. I was surprised, how many stations and countries can be decoded down to 80 and 160 m.

Further Information

Talk given during SARTS monthly meeting

PSK reporter link to stations currently received by 9V1KG

CQ WPX SSB 2020

CQ WPX over … stn closed. Poor propagation, could not improve from last year. But 850 qso and 700k points in low power is also not bad. 🙂 4E1A

CQWW DX Contest SSB 2019

Last weekend I participated in the CQWW DX contest SSB part under the call sign 4E1A. Propagation was miserable on 40 m and 80 m; with my 100 W low power I was seldom heard by DX stations in EU or NA. On 20 m and 15 m propagation was acceptable, and I got even some openings on 10 m. Finally, I could exceed my points from 2018 and made 852 contacts with 62 DXCC entities and in 30 zones.

Contacts per band. Total 2287 QSO points and 191 Multipliers.

Raw score: 2287 QSOs x 191 multipliers = 436817 points.

NSPH 2020 – Participants’ Image Gallery

Uploaded Pictures

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NSPH 2023

Staying Connected

Date: ~~June 13, 2020~~ NEW: April 15, 2023
Time: tbd.
Location: tbd.
Fees: 700 PHP per participant

After the COVID-19 pandemic the meeting was rescheduled to April, 15th, 2023. Place and time to be defined. We will inform all registered participants about new plans and schedules on this website.

Online registration is open now! Please register here. Fees are 700 Pesos per participant and additional donations are always welcome. After your registration you will receive a confirmation email. Please transfer the amount due to the following account:

Account name: Normita D Torres or Violeta T Rivera or Emil L Virtudes
Account number: 1599-5781-33
Bank: BPI
Branch: BPI ATC Alabang

and email a copy of the bank slip with your name written on it to Mita (mita0955@yahoo.com ) , Zedith (solid_zedisu@yahoo.com) or Violeta (violetarivera736@yahoo.com).

You can upload your picture on the picture upload page. Pictures will be shown in the NSPH 2020 participants’ gallery.