NJDTechnologies

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Current Operating Frequency and Mode

CQ 474.5 kHz CW

Building a Station for MF or LF at Reasonable Cost by Rick, W7RNB / WI2XJQ

– Posted in: 630 Meter Instructional Topics, 630 Meters

Building a Station for MF or LF at Reasonable Cost
October 23, 2016
by
W7RNB

As interest grows around the MF (630meter) and LF(2200meter) bands there are considerations to be made with regards to what equipment to use as the base plate of your system. This is only one approach, but one that seems to work quite well and is within reach as far as cost. A study was done with what possible radios would would receive both the MF and LF bands, run low power output to drive a transmitting converter, and that would be easy to make work. The Alinco series radios fit this criteria. The DX-SR8 is a general coverage receiver that has great statistics for consideration of MF and LF bands. It uses built in filters for low frequency receiving, and is very stable at 1PPM and is quite easy to use. The transmitter is the DX-SR8T and a transmitting down converter. The advantage of this radio is that it is easy to lower the output power to less than one watt and its stability is also 1 PPM. The third part of the “Alinco station” is the Signalink USB control made by Tigertronics. This unit is connected to your computer and does all of the signal control necessary for the twins. It is easy to install and is quit user friendly for all digital modes, including WSPR. Below is a picture of the complete station setup.

w7rnb

Alinco DX-SR8T transceiver w/ Signalink on the left and DXSR8 receiver on the right.

 

As can be seen from the photo, the station is quite simple with the transmitting converter stuck in between the two radios. Again, this is only one approach to getting on either or both of the bands. One has to start somewhere and this might be a good place to begin. Pricing was not mentioned here because it depends on how good you are at scrounging for the lowest prices. Both radios are currently available on all the popular selling sites.

Here are some of the specifications of the Alinco DX-SRx series radios –

RX:
Coverage
150Khz – 30Mhz
Frequency Stability 1ppm
Dual conversion
Sensitivity 0.25uv to 1uv depending on mode and frequency range.
First IF 71.75Mhz
Second IF 455Khz
Spurious rejection >70db

TX:
Super low power output is one watt tunable down to near 1⁄2 watt