New transceiver Yaesu FT-920

It was time for replacing my old Kenwood TS-850 transceiver. The TS-850 has served me well, but it was getting old, and a new HF transceiver was in the pipeline.

I found a fine offer on the Danish second-hand site ham.brugtgrej.dk. An Yaesu FT-920 was for sale in mint condition. The FM-unit and a 250 Hz CW crystal filter were included. I studied the FT-920 reviews on eham.net before contacting the seller. I bought the transceiver on the spot, and transferred the payment via web banking. A big parcel arrived two days later.

The FT-920 is a medium-class transceiver - it is not a contest machine. As I only participate in contests a few times a year, this transceiver will probably fill my needs.

Here are some pro & contra statements regarding the FT-920:

Pro FT-920

• There are two VFOs with each their own display 
• There are 2 antenna ports and one “receive only” port.  
• The DSP works at audio frequencies and can be switched off
• The noise blanker is excellent
• The CW operator is spoiled with functionality
• The RF output can be turned down to the mW level
• The 6m band is included (100 W output)
• The RX is pleasant for long-time listening (according to reviews)

Contra FT-920

• No 2m/70cm band
• No dual receiver
• No option for SSB crystal filter
• No dedicated transverter port 
• No band-scope 
• The cabinet is big and heavy

My new transceiver Yaesu FT-920.

Time will tell if my new purchase turns out to be a success. Right now, I intend to work JT65/JT9 on HF and collect countries for my future QRP DXCC award. 

OZ1BXM Lars Petersen
Homepage: oz1bxm.dk

Moving the VHF antennas

My current VHF antenna system is positioned just between my own house and my neighbour's house. Both houses are terrace-houses, and a part of the antenna is above my neighbour's roof.

I am working to extend my VHF antenna system in order to operate EME, and more space will be needed. That is why I have decided to move the VHF antennas towards the center of my garden.

In the picture below, you can see how a 6 meter long steel tube (diameter 50 mm) will serve as the lower part of the antenna mast. The upper part (not mounted yet) will be a steel tube which is going to be rotated by a Yaesu rotor.

The new antenna mast.

The construction is to begin ASAP. I will report how the work is progressing in a later update.

73, OZ1BXM Lars Petersen
Homepage: oz1bxm.dk

WAZ wallpaper received

I earned WAZ some time ago. Upon submitting my application, I received a message, that my application was approved and an award number was issued. About 6-8 months later, the wallpaper arrived in the mail. It was a great moment holding the real certificate in my hand!

WAZ #9053 Mixed Mode.

I have now completed my homepage on this pursuit: In pursuit of WAZ - done. 

The next award I will be chasing is QRP DXCC from ARRL. My currrent standing is 85 entities.  

73 from OZ1BXM Lars

Homepage: oz1bxm.dk

1 kW dummy load with fan cooling

I was looking for a big dummy load in connection with my EME-project. Output 1 kW at 144 MHz from the SSPA cannot be terminated into small dummyloads. I needed a "grown up" load.

I decided to build a dummyload with active cooling. A big heat-sink was found on Ebay.de. It was converted into a heat-duct and 2 large fans were fitted at one end. The heat duct was mounted vertically so that cold air can be taken in below, and hot air will be blown out on the top.

Two 800 W resistors, each 100 ohm, were connected in parallel to serve as one large 50 ohm resistor. The resistor array was covered by a metal box to avoid RF radiation. A heat sensor was employed so the heat sink temperature can be displayed on an external digital voltmeter.

1 kW dummy load. Two large fans provide cooling.

The dummy load works to my satisfaction. The frequency range is 0 - 500 MHz. The SWR at 

144 MHz is 1.3. I can now run SSPA tests at full power for long periods of time without overheating.

73 from OZ1BXM Lars Petersen
Homepage: oz1bxm.dk

2 x 8 element yagi for EME

Which type of antenna is suitable for EME? I have been pondering this question for a long time. Now I have decided to put up two 8 element yagi antennas with elevation. They will be mounted vertically, and they will fit nicely on my roof due to their modest size. The array will be elevated by my Yaesu G-550 rotor.

One of the deciding factors in choosing this array was Moon time. Using elevation, many operating hours each day will be available.

Another factor was simplicity. It is easier to mount two yagis vertically than horizontally, and the mechanical balance is good.

Two 8-element yagis.

What is the expected gain of this array? As each 8 element yagi provides 11 dBd, an array with two antennas should provide 3 dB more; that is 14 dBd (25 times). I hope this antenna gain is sufficient for EME with JT65B. By using 1 kW of output power from my newly built SSPA, the total ERP on 144 MHz will be 25 kW.

OZ1BXM Lars Petersen

Wireless internet access

A ham operator needs connecting to the internet when travelling or operating outside his QTH. But why does a ham operator need internet access?

• Download DX information, e.g. from DX Summit
• Upload log files, e.g. to Clublog
• Upload contacts to eQSL and LotW
• Synchronize PC-clock with NTP server (when running JT65 modes)

To enable mobile internet access, I've purchased a Huawei Mobile Broadband USB surfstick (see picture below). The USB surfstick contains a 2G/3G modem. The modem is only used for data transport, not for speech. This device enables internet access in most locations in Denmark.

Huawei E3531 Mobile Broadband modem with SIM card (top cover removed).

Installation is super easy. Just plug the surfstick into your Windows 7 PC and wait for the drivers to install. The surfstick has a local homepage, where you can follow data sent and received, and monitor the signal strength. 

My operator is OiSTER and they utilize the mobile network owned by 3 Denmark. Roaming is not allowed. 

OZ1BXM Lars Petersen

Homepage: oz1bxm.dk

Vacation

Time for vacation! I'll return to this blog with new contributions in September. Until then: Have a nice vacation, all of you!

73 from OZ1BXM Lars Petersen
Homepage: oz1bxm.dk