Marius Lubbe ZS1ML
Hello there, fellow radio enthusiasts! Today, I want to talk about a nifty little device that’s been a game-changer in my shack – the MFJ-1708B. Now, if you’re like me and you love playing around with Software Defined Radios (SDRs), you’re going to find this gadget particularly interesting. It’s designed to automatically switch an antenna between a transmitter and a receiver when keyed, which is super useful if you’re using an SDR as a panadapter. But more on that later!
What’s a Panadapter?
Before we dive into the MFJ-1708B, let’s take a moment to talk about panadapters. A panadapter, or panoramic adapter, is a device that allows you to visually see the RF spectrum and waterfall on a traditional analog radio. It’s like having a bird’s eye view of the band you’re operating on. You can see signals that are on the air, and it’s a fantastic tool for finding open frequencies when you’re looking to make a contact. When used with an SDR, a panadapter can provide a wide, high-resolution panorama of the band, enhancing your ability to pick out weak signals amidst the noise.
Understanding the Waterfall
Now, you might be wondering, what’s a waterfall? Well, in the context of a panadapter, a waterfall is a visual representation of the spectrum over time. It’s a dynamic, moving graph that shows the intensity of signals across different frequencies. The color and brightness of each ‘drop’ in the waterfall indicate the strength of the signal, with brighter colors typically representing stronger signals. This makes it easy to spot signals at a glance and track their activity over time.
With the right settings, the waterfall can also be used as a CAT control device. CAT, or Computer Aided Transceiver, is a system that allows a computer to control the functions of a radio. By clicking on a signal in the waterfall, you can tune your radio to that frequency. This can be a huge time-saver, especially when you’re dealing with a busy band.
What’s in the Box?
When I first got my hands on the MFJ-1708B, I was pleasantly surprised by its compact size. It’s a small, unassuming box, but don’t let that fool you – this little guy packs a punch! It comes with a few connections – one for the SDR, one for the radio, and one for the antenna. There’s also an adjustable delay feature and a PTT ground connection on the back.
Setting Up
Setting up the MFJ-1708B was a breeze. I simply connected my SDR to the SDR connection, my radio to the radio connection, and my antenna to the antenna connection. The adjustable delay feature is a nice touch – it allows you to keep the transmit line open while you’re talking, which can be really handy. I also decided to use the RF sensing feature, which senses when a signal is transmitted and automatically switches the SDR out of the transmitter loop in order to protect it from high RF power, which can hurt it.
In Action
Once everything was set up, it was time to put the MFJ-1708B to the test. In receive mode, the center pin goes to the SDR and to the radio at the same time. As soon as I pressed transmit, it grounded the center pin of the SDR and just allowed the RF to transmit from the radio through to the antenna. It worked like a charm!
YouTube Videos
If you’re more of a visual learner, there are plenty of YouTube videos out there that provide reviews and tutorials on how to use the MFJ-1708B. I found these videos to be a great resource for getting a visual understanding of how the device works and how to set it up with my specific equipment.
Conclusion
All in all, the MFJ-1708B has been a great addition to my shack. It’s a useful tool for those looking to use an SDR as a panadapter, and I’ve been really happy with its performance. Just remember to carefully read the instructions and understand the device’s limitations before using it. As with any piece of equipment, your experience may vary based on your specific setup and needs. But for me, the MFJ-1708B has been a winner!
Remember, this is just my experience and your mileage may vary. Always make sure to do your own research and testing to ensure a device meets your specific needs and requirements. Happy DXing!
