AT-2000 coupler from Mizuho, Japan - part I.

Hello,

listeners and DXers often encounter the need for preselection or some version of a bandpass filter at the input of their often very wideband receivers.

One option is factory equipment, which is sometimes available on online marketplaces such as eBay.

One of these is the AT-2000 coupler, which was manufactured in the past by the Japanese company Mizuho. (also made by Global and some others)

This unit should cover 0.5 - 30MHz range and would be able to work with wire antennas and in/out impedance range 50-600 Ohms. Unfortunately, do not expect the balun transformer in between unbalanced and balanced antenna input.

Here is what you will get when you purchase it on the flea market. In most cases it is in good conditions...

This coupler circuit applies the Pi-match method, and the "heart" of the unit is 25mm diameter single layer winding coil.

User manual to download

Air band BPF from DD Amtek

Hello,

After posting an article about a cheap BPF for Air band from China, I received few emails asking if I knew of a better filter.

This filter is equipped with BNC connectors and is available for around €20.

Band pass filter for the VHF Air Band prevents overloading of the receiver by interfering signals outside the air-band.

Pass band 112 – 140 MHz

RX only

Insertion loss within passband: 2 dB typ.

Rejection of the range 0 – 100 MHz: min. 40 dB (typ)

Rejection of signals above 155 MHz: min. 40 dB (typ)

Input/output connector: BNC

Input/output impedance: 50 Ohm

Size: 33 × 71 × 18 mm

Weight approx.: 35 g

Here is what you can expect from this unit in reality. Be note that attenuation is lower for about 0.5dB due to connected coaxial test cables and all used adapters as it was not compensated in this case.

Compared to the measured data on the VNA screen, the actual insertion loss within the passband is only 2.1-2.1dB due to non-compensated added test cables and adapters. I did not reach -40dB up to 100MHz or above the 152MHz but in overall, this filter works very well together with my LNA and Diamond vertical antenna on the roof.

Air band BPF from AliExpress

Hello,

if you are Air traffic listener or Air band avid DXer then maybe you are thinking about the cheap Air band bandpass filter for your wide band scanner. Especially when you are using the wide band antenna on the roof the overloading from VHF FM BC signals is common issue.

Here is what you will get if you order the cheap Air band BPF from AliExpress.

Well, here is what you can expect from this unit in reality. Be note that attenuation is even lower for about 0.4dB due to connected coaxial test cables and all used adapters as it was not compensated in this case.

Check the values and order it only if it fits to your needs, otherwise forget it to avoid disappointment.

Listenning to Radio Praha

Hello,

when I am talking to people about the ham radio activities lot of them asking me what the SWL or BC SWL is and how it can be attractive these days...

My one of the favorite BC stations > local Radio Praha very foolishly terminated broadcasting on the LW, MW, and SW bands from their domestic transmitters so listeners can find them only from US relays or on VHF FM, DAB+, Sats or Internet respectively.

SHORTWAVE

Radio Prague International’s English and Spanish broadcasts can be heard in North America on the frequencies 9955, 9395, 7780 and 5010 kHz via Radio Miami International. For the broadcast schedule, see www.wrmi.net.

SATELLITE

Radio Prague International’s broadcasts in all languages are transmitted in Europe via Astra 3B satellite, 23.5° east, 12,3435 GHz; choose the transponder 3233 with the central frequency of 12,3435 GHz and the polarization Horizontal in the DVB-S2 system.

Also look for rebroadcasting schema here:

Ways to listen | Radio Prague International

Luckily, they are preparing different kind of QSL sets for each year and in the past, you could be also surprised with gift in the post box like me...

QSL policy

As of January 2025, they will send a QSL electronically to everyone who sends a reception report. Only those who send them a reception report by post will receive a printed QSL.


73 - Petr, OK1RP 

Radyo Pilipinas from Tinang in Tarlac on 9370kHz AM

Radyo Pilipinas (RPWS) on 9370kHz AM - 1Dec2025 (Sony ICF-SW20)

   Date: 1/12/2025

   UTC time: 17:30

   Frequency: 9370kHz

   Mode: AM

   Station: Radyo Pilipinas World Service (RPWS)

   Signal report: 4444 SINPO > 60dBuV/10dB S/N

   Program: National Anthem of Pilipinas for re-launching 

   the SW BC transmission again

   Transmitter: Tinang transmitter site in Tarlac

   Country: Pilipinas

   Receiver: Sony ICF-SW20, Japan

   Antenna: Vertical antenna at 11m height and 

   preamplifier

It broadcasts in Pilipinas also in English language. Radyo Pilipinas World Service uses the relay transmitter facilities of Voice of America in Tinang, Concepcion, Tarlac Province for its broadcast purposes.

I would like to send you big congratulations for your big come back to the shortwaves and I hope that you will be one of the most popular SW stations in the world!

BBC 5 Live from Brookmans Park, UK on 909kHz AM

BBC 5 Live on 909kHz AM - 1Dec2025 (Sony ICF-SW20)

BBC from Ascension on 11660kHz AM

BBC on 11660kHz AM - 21Nov2025 (Sony ICF-SW20)