Today I came across a much needed update to the mat-705 antenna tuner, for the Icom IC-705. The original tuner had issues with battery life, indicators falling out during battery replacement, and users forgetting to turn the device off, to conserve power.
We’ve seen amazing things from small companies recently, so we understand the double-edged sword of rapid development and flexible production changes, compared to their megacorp counterparts. It seems in this example, the manufacturer of this antenna tuner heard the cries from the community, and adapted pretty quickly.
There are 5 new updates which need to be presented.
- There’s no longer at 9 volt battery inside. The tuner now uses two rechargeable Lithium-ion batteries. This means we no longer have to open the device, to change out the battery.
- The internal batteries are now charged by a USB-C port on the front panel. This mod alleviates the need to buy stock in a 9-volt battery company, since the batteries are built in. Charging rate is said to be 500ma, and take about an hour to replenish.
- The indicator lens which used to pop out when disassembling the tuner, have been replaced with an LED now attached to the tuners circuit board. This means no more lost lenses when replacing the battery in the field.
- This update also removes the on-off switch, which was the cause of so much “dead battery” confusion in the original version.
- With the removal of the power switch, the Plus versions power is now controlled automatically, by the transmitter. With the control cable connected, the tuner will be turned on or off along with the transmitter.
What the update from the manufacturers website doesn’t say, is whether or not battery life has been improved. If we consider how the Elecraft T1, and the LDG Z100 Plus utilize latching relays, the result is a near zero current load, while not tuning. It also gives us a ridiculously long battery life, counted in months, not days. So it would be reasonable to expect better battery life from this new Plus version, even with rechargeable batteries.
As you may already know, I just recently received the Elecraft T1, for field testing with the Icom IC-705. The T1 is an excellent manual tuner, but there is no interface for Icom radios. This means manual tuning only until one becomes available. I have also tested the LDG Z100Plus with the IC-705. Although it sets the benchmark for functionality, it is too big for QRP field work. We passed on the original mat-705, deciding instead to wait for the Icom AH-705. With this new mat-705plus, perhaps it is safe to go ahead pull the trigger on it (available 01, 2021), since the AH-705 still has an unknown release date. Either way, all of these tuners will eventually find their way to 65 North for field testing with the IC-705, TX-500, and FT-818. If you’d like to help support these tuner acquisitions, you are welcome to drop something in the kitty below.
Original article on the Mat-705plus model here
Download mat-705Plus Instruction Manual (V1.0)
So why so much talk about tuners? There are often some very narrow minded opinions thinking we should always use resonant antennas. Often my own opinion is amongst them, but not always. There are times when a broadband antenna like a 9:1, 5:1, 4:1 random wire with a tuner, makes much more sense than a single band or multiband resonant antenna. The truth is, there are times I am working NVIS on 80m, 60m, 40m, but also want comms outside my region on 30m, or 20m. I can string up an endfed random wire which has good performance on 80 and 40m, but gets decent performance on 60, 30 and 20 meters as well. Now I don’t need to get frostbite (again), trying to get a fan dipole a couple of wavelengths up in a tree, when the temperature is -20 outside my shelter. Naturally we expect to lose some performance with a tuner, but I’m not always trying to work DX with QRP power. Using 500hz Vara HF or ARDOP 500 with Winlink, slow or normal JS8Call, 5 watts is enough any time of day or night to work any station in Scandinavia. Naturally this assumes operating on the right band at the right time. There are also alternatives to using an antenna tuner. One of them is the DX Commander. Undoubtedly a full size quarter wave vertical with sufficient counterpoise or radials, will outperform a broadband antenna. However ease of deployment, speed of deployment, and the ability to set up on a postage stamp, often makes such antenna systems cumbersome for rapid deployment, never mind setting them up alone in poor wx. This is when we begin searching lighter, easier to deploy broadband systems, either terminated, or using an antenna tuner.
I have been looking for impedance tuning range for the mAT-705, but all I can find is comment it tunes over wide range. The Icom AH705 also only talks about working with long wire. I have LDG Z100plus, works well, and since can handle 100W can be used with other higher powered rigs if I like. I use with my IC705 for NAQCC park events, works very well. It’s tuning range is 10:1.