This weekend LF and MF time!

After much time doing only microwaves activities, I listened the encourage words from Luis EA5DOM, to try to receive LF and MF . Luis is active in 136kHz and 477kHz in TRX and uses Opera, WSPR and have a SpectrumLab grabber.

Icom IC-R9000 and IC-781 used

Icom IC-R9000 and IC-781 used

On the right the PA0RDT mini-whip antenna

On the right the PA0RDT mini-whip antenna

I build a PA0RDT mini-whip antenna and erected it 6 meters over the floor, as receivers I used my Icom IC-R9000 for 136kHz and the  Icom IC-781 for 477kHz. I tested Opera, WSPR and Argo for QRSS.

WSPR-2 stations in 477kHz

WSPR-2 stations in 477kHz

WSPR-15 signals in 136kHz

WSPR-15 signals in 136kHz

Opera32 stations in 136kHz

Opera32 stations in 136kHz

G3XDV in slow CW QRSS/60 in 136kHz

G3XDV in slow CW QRSS/60 in 136kHz

DK7FC in DFCW in 136kHZ

DK7FC in DFCW in 136kHZ

The most common modes are OPERA32 (32 mins period), wspr15 ( 15 mins period) in 136kHz, and OPERA-8 (8 mins period) WSPR-2 (2 mins period) in 477kHz. The OPERA and WSPR uploads to Internet the receptions as spots and is possible check online the results and distance. This is feature is very nice to compare results with another stations.

wsprnet.org map with the WSPR-2 stations received in 136kHz

wsprnet.org map with the WSPR-2 stations received in 136kHz

pskreporter.info maps with the OPERA-32 stations received at 136kHz

pskreporter.info maps with the OPERA-32 stations received at 136kHz

I’m really surprised for the good results and for the nice signals that can be received in this low frequencies with a small antenna. I know that this band some times not are easy for the local QRM/QRN generated by switched power supplies, motors, etc.. but with not much effort is possible get some setup to receive this bands.

I encourage that you try to receive this bands. A good point to start is the 477kHz band. It can be received easy using a base HF transceiver and antenna.

Cheap and easy to build 1296MHz EME feedhorn for offset dishes

Recently I build a circular polarization feedhorn to try to do EME in 1296 MHz. The hint was that it have very easy to build and cheap. I was looking some designs based in ual mode septum designs from N2UO and RA3AQ but they not are easy to build for me. My idea has been use fireplace pipe and a dielectric depolarizer.

1296 Dual mode feedhorn

1296 Dual mode feedhorn

To build the feehorn I have used fireplace inox pipe of 150mm and a galvanized reduction from 250 to 150mm. The dielectric depolarizer is a piece of Rogers Duriod 5880. To try to minimize the number of sma connectors, I used a small piece of Suhner .141 as a probe that will connect directly to the LNA saver switch.

Building the RX probe

Building the RX probe

RX port probe

RX port probe

Feedhorn inside

Feedhorn inside

In the TX port I used a standard N connector. I measured the RL in the lab, but have to measure the RL in the dish for this reason the bottom plate not is soldered yet, it is glued using metalic tape, until the RL is adjusted on the dish.

Measuring return loss

Measuring return loss

Feedhon on the dish

Feedhon on the dish