There are certain things in amateur radio that just will not go away and many of them are absolutely incorrect. One of them is calling an impedance matching network a tuner. These things do not tune anything.
What they do though is match the conjugate impedance or the antenna to the 5 0ohm output of the transmitter.
I first saw one of these at a Field Day site several years ago. I looked it over. I was allowed to remove the lid to look at the inside.
What I liked was the unique method Nye Viking used to make a roller kind of inductor from a fixed inductor.
My question was how good does it make contact and will it arc. (see the end of the post)
I did not know then it was electronically identical to the Nye Viking MB-I-01 and MB-I-02.
The only differences is the meter placement on the ICOM is to the left and a dimmer pot for the meter lights is placed on the right.
The MB-I-01 is the same without the dimmer, and the meters are to the right and the Viking ship logo on the left.
The MB-I-02 has an antenna switch to select coax 1, coax 2, or a wire wire antenna using the coupler's internal balun.
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| ICOM MT-100 |
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| Inside |
Looking at the track of the contact there is a line of dirt. At first I thought arcing, but there is no pitting on the contact or inductor winding when I wiped off the dirt with a rag dampened with denatured alcohol. Normally, arcing not only leaves carbon behind, it also leaves pitting due to the arc's heat.
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| Method of making a fixed inductor similar to a roller inductor. |
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| Rear View |
There is very little on line about any of these antenna couplers. Mine came with a clean copy of the manual so I added a link to the file.
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| Nye Viking MB-I-02 |
The front of the Nye Viking coupler is identical for both models unless at some time the antenna switch was changed to the front.
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| Inside |
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| Rear |
The images came from on line, but I forget where. I found them in my directory of antenna accessories.
How does the MT-100 work?
Before I get to that, I will mention the capacitors in these are properly calibrated. With the pointer knob at 0 (zero) the capacitance is Minimum and with the pointer knob at 10 the capacitors are at Maximum capacitance. No need to open these and make the correction like with MFJ and Dentron as well as many other brands.
Now for operation...
I've been using it on a Mosley RV-4C without issue. Then, that antenna needs very little tweaking with any coupler.
I then used it on my home-brew 17 foot vertical shunt-fed antenna on a trailer hitch mount on my pickup truck. I was able to make QRP contacts as far as Oregon and California as well as SSB using 25 watts to Wyoming, England, and Italy. I only operated about an hour or two so this is only a sample.
Measuring input power to the coupler and output to the antenna I had no appreciable loss in the MT-100.
I decided to try it with my FT-101ZD at 100w on SSB and a Sigma-Eurocomm SE HF-X80.
Using this set up I was better able to measure input power to output power and find that there is only a few watts of loss on 80m and 160m. Input on all bands was 90 to 100 watts and output from the coupler 89 watts at 90w and about 98-99 using 100 watts on 80m and 160m.
Oh, but that antenna is not to do 160m. It works fine. I used it on A.M. and made contacts in CO, TX, and ME as well as a few states close to my QTH. Later I worked stations in the EU and Africa. I was actually surprised anyone was on A.M.
There are plenty more tests to do with various antennas, but I find the unit, like most of my non-MFJ couplers, will outperform any MFJ on any power on any band because even my MFJ 949E does not do very good on 160m and not all that good with any of my compromise antennas on 80m. The MT-100 will match them.
How does it compare to my Ten-Tec* and Dentron couplers; about the same to 160m where the MT-100 matches a bit narrower BW. I might get 15 to 20 kHz with the Ten-Tec and Dentron units and 5 kHz to 10kHz with the MT-100. Everything seens antenna dependent.
What about arcing of the inductor contact? When I received the MT-100 the first thing I did was look for signs of arcing. I do this with all used couplers I get.
Nothing. No sign of arcing on the inductor or contact. Nothing on the capacitor places.
In use I intentionally tried to get it to arc using 100W SSB and A.M on a 31 foot Jackite vertical that has an interior wire. It is the same Jackite pole I used in this post for a 20m inverted-V antenna. So far I do not see any trace of an arc.
* don't use more than 25 watts with any Ten-Tec coupler I have. I do not trust much power with the toroid design they use, but then many Ten-Tec users I know only operate QRP.
73
