I have a M103C, I purchased it new back the in 90's, it still works, but ditching it for a M104C or a homebrew 5 Element on a short boom (16 foot boom).
With the Beam on Vertical, sometimes stations heard me exactly the same on the M103C vs my Maco V5/8. Sometimes they said the 103C was stronger, this was with both antennas on Vertical. Not much gain over a groundplane antenna on vertical, only benefit to M103C vs Groundplane was the rejection of the M103C it does have suprising rejection, works quite well so you don't have to hear garbage coming from South of the Border.
I finally put the M103C on Horizontal, and it seemed to work much better, especially since it was only 30 feet or so above ground. For Example, If I was to talk to someone on a dual polarity beam like a Moonraker 4 on Vertical with my V5/8, and then I'd switch over to the 103C on Horizontal and they would switch over to the Horizontal side of the Moonraker 4, the signals came up dramatically, several S-units, and the "noise level" was very noticeably lower also. So I would say M103C on Horizontal, definitely worth it, thumbs up, on Vertical, Meh... Go for a M104C or bigger on Vertical if you want a Vertical Beam. The M103C might as well just be a rotating groundplane on Vertical, with the only benefit being rejection, no real gain over a 5/8 groundplane antenna as far as TX or RX strength. Someone had suggested to me once to remove the Gamma Match, as it has some loss associated with it, and break apart the driven element and drive it directly with some type of new matching system with no loss, can't remember the name now, but it's quite popular in the Ham world now, new since 1990 or so if I remember right. Anyway, they said if I did that I would pick up a little more gain because the gamma match system is lossy.
Personally I am done using HF Beams on Vertical, it's seems a waste, and from now on, if I want to talk Vertical P. I will just use my Imax 2000 or whatever groundplane antenna I am running at the time. The M104C or if I build a homebrew 5 element on this extra 16 foot boom I have laying around is definitely going on Horizontal Polarity only and tuned for 10 meters. It's nice to be able to bust up things on 10 meters when needed and any beam on Horizontal is a good start...
With the Beam on Vertical, sometimes stations heard me exactly the same on the M103C vs my Maco V5/8. Sometimes they said the 103C was stronger, this was with both antennas on Vertical. Not much gain over a groundplane antenna on vertical, only benefit to M103C vs Groundplane was the rejection of the M103C it does have suprising rejection, works quite well so you don't have to hear garbage coming from South of the Border.
I finally put the M103C on Horizontal, and it seemed to work much better, especially since it was only 30 feet or so above ground. For Example, If I was to talk to someone on a dual polarity beam like a Moonraker 4 on Vertical with my V5/8, and then I'd switch over to the 103C on Horizontal and they would switch over to the Horizontal side of the Moonraker 4, the signals came up dramatically, several S-units, and the "noise level" was very noticeably lower also. So I would say M103C on Horizontal, definitely worth it, thumbs up, on Vertical, Meh... Go for a M104C or bigger on Vertical if you want a Vertical Beam. The M103C might as well just be a rotating groundplane on Vertical, with the only benefit being rejection, no real gain over a 5/8 groundplane antenna as far as TX or RX strength. Someone had suggested to me once to remove the Gamma Match, as it has some loss associated with it, and break apart the driven element and drive it directly with some type of new matching system with no loss, can't remember the name now, but it's quite popular in the Ham world now, new since 1990 or so if I remember right. Anyway, they said if I did that I would pick up a little more gain because the gamma match system is lossy.
Personally I am done using HF Beams on Vertical, it's seems a waste, and from now on, if I want to talk Vertical P. I will just use my Imax 2000 or whatever groundplane antenna I am running at the time. The M104C or if I build a homebrew 5 element on this extra 16 foot boom I have laying around is definitely going on Horizontal Polarity only and tuned for 10 meters. It's nice to be able to bust up things on 10 meters when needed and any beam on Horizontal is a good start...
