Welcome to Tropical band

To most people the phrase "tropical bands" bring a pretty clear picture to mind - a bunch of shirtless guys playing calypso music. But to experienced shortwave DXers those two little words express the most challenging and enjoyable part of the radio hobby. The phrase kindles memories of a DXer's best catches and favorite QSLs, of exotic stations, music and of early morning listening sessions. (Don Moore)
I like the "Tropical band" name for new 60m allocation. (OK1RP)

Effective from 1st Jan 2017 please paper QSL via OM-bureau only.

Friday, March 1, 2019

DARC: Radar makes 5 MHz band 'useless' !

Germany's DARC reports: Once again we have problems with short wave radars. On almost every evening at 5310-5410 kHz the Russian coastal radar 'Sunflower' broadcasts. This also makes our new miniband useless

A Google translation of their post reads:

The system is located near the city of Makhachkala on the Caspian Sea. Acoustically we perceive it as a deep hum. It transmits in FMOP (Frequency Modulation On Pulse) with 43 sweeps / sec and captures aircraft at a range of up to 450 km.

Over water ships are recognized. Even stealth planes can be classified. The system is so successful that the Chinese operate several "sunflowers" on the east coast. Chinese OTHs (Over-Horizon Radars) work almost daily in the 20-meter band. 

In the mornings we can often receive them with high field strengths. They send in blocks of several seconds and jump over wide frequency ranges. Very noticeable is the radar, which resembles a foghorn sound (66.6 sweeps / sec). The worst "QRM brooms", however, are the broadband radars of the Chinese. They work with 10 or 20 sweeps / sec and a signal width of 160 kHz.

In the mornings we find them in the 20 m band and in the evening also in the 40 m band. There they are particularly noticeable when the transmission line is in the dark. At the moment we have extreme problems with the new Container Radar from Russia. It works as an over horizon radar in FMOP with 40 sweeps / sec and a signal width of about 40 kHz often for hours in the 20 m band. In the past few days we see two systems side by side on our SDR screens. 

The station is located north of Penza and not far from Saransk. On the S-meter we see S9 + 40 dB and sometimes +50 dB. The DARC-Bandwacht has informed the BNetzA-Konstanz [Federal Network Agency].

Please visit the Bandwacht website again and again and click on the current intruder

The newsletters are also recommended. The image material there should also serve for further education.

The website of the Bandwacht and the IARU monitoring system is

This is reported by Wolf Hadel, DK2OM, from the DARC-Bandwacht.


Note: The question is if it is the issue and blocking point for ham radio operation on the 60m band as there is NO ham radio traffic at all for several months. Just PC controlled CB chats...

73 - Petr, OK1RP

1 comment:

  1. As far as I know we as radioamateurs are using the 60m as secundairy users. The militairy is the primairy user. I don't think we can do anything to stop radar transmissions. Is the band useless now? Yes, for SSB it is. But CW and digimodes are still readable, although a weak signal is always a problem of course. Therefore you need a inventive system to cancel the disturbance out, that should be no problem for us experimenters. 73, Bas