The mast is set at 25 ft tall and that puts the Gain Master 13 ft above the
roof.
I was transmitting on the a.m. side.
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New antenna from Sirio Gain-Master
- Thread starter dxswe
- Start date
The mast is set at 25 ft tall and that puts the Gain Master 13 ft above the
roof.
I was transmitting on the a.m. side.
What if it's mounted horizontally at the correct height for additional ground reflection gain?
Hello!
Sure it could have that amount of gain, but it would still be misleading.
Gain is referenced in freespace compared to either a isotropic (dBI) or a dipole (dBD)
If a car goes 100 miles an hour it goes 100 miles an hour compared to a speed of : 0 .
If i run in the opposite direction of the car with 10miles/hr ..the car would go 110 miles per hour (at least for me..).
Though we all know that isnt the way to esthablish a fair figure.
If gain is referenced to anything other than the above it should be mentioned.
Not only the height but also things like ground conductivity etc.
Kind regards,
Henry
All about antennas
Sure it could have that amount of gain, but it would still be misleading.
Gain is referenced in freespace compared to either a isotropic (dBI) or a dipole (dBD)
If a car goes 100 miles an hour it goes 100 miles an hour compared to a speed of : 0 .
If i run in the opposite direction of the car with 10miles/hr ..the car would go 110 miles per hour (at least for me..).
Though we all know that isnt the way to esthablish a fair figure.
If gain is referenced to anything other than the above it should be mentioned.
Not only the height but also things like ground conductivity etc.
Kind regards,
Henry
All about antennas
That "...correct height for additional ground reflection gain" varies from place to place because of the various levels of ground conductivity. Even so, the amount of 'gain' it will have is still probably not going to be real close to that quoted by the manufacturer, which is almost always slightly 'optimistic'. At the very least, subtract that 2.15 dB from the 'dBi' figures to get 'real world' figures. That's absolutely normal for converting 'dBi' to 'dBD'. (Then you can deduct whatever 'they' attribute to 'optimism'. 
)
- 'Doc
)- 'Doc
well after reading last 5 pages or so is it safe to say
this lives up to the hype.or is it just a flop. i seen
its power handling is down somewhat. but seems to me
thats theres alot more positives with this.and lastly on a
scale on 1-10 with 10 being the hardest how would you
rank the assembly.i seen the instruction sheet myself
looks vague at best ,might be better in person i guess
this lives up to the hype.or is it just a flop. i seen
its power handling is down somewhat. but seems to me
thats theres alot more positives with this.and lastly on a
scale on 1-10 with 10 being the hardest how would you
rank the assembly.i seen the instruction sheet myself
looks vague at best ,might be better in person i guess
I would rate it a 10 for what it does and with the reports that I get from stations I talk to.
as far as power handling those that want to push a KW or more won't like it.
But as far as I'm concerned 500 watts is enough.
Great antenna, I would buy another with out a 2nd thought.
If you can live with the 500 watt limit, for me the SGM is the best all around antenna on the market. It has a very broad bandwidth, shows me absolutely NOOOOOOOO!!!! TVI or tendencies to do so, is very effective on the air for both local and DX, an when you lay this one all out to assemble, you will see how easy and simple it is, with absolutely NOOOOOOOO!!!! tuning necessary and it looks fine to work from 26.300 to 29.500 mhz according to my SWR bandwidth curve chart.
When I recently compared my CB vertical antennas against the SGM in side by side testing, I only found my A99 and my I-10K matched it in my averaging the signals on my reports. I'm currently testing my antennas on just one mount and all antennas on at the same height, so we'll see. During this process I have been remounting my Marconi 7x homemade jobber up beside several in this series and doing some more side by side, but all the test reported will be with only one antenna at a time.
I would surely recommend the SGM as an excellent buy, but I'm not happy about H & Y raising the price $50 the next month after selling out of their very first order in November 2010.
Well I had a Gainmaster from very early on and posted four videos on Youtube of our findings in the UK. Mine is on a lattice tower and stood up well to the UKs worst winner for many years with heavy snow and temperatures down to -17 C.Then a few weeks ago we had 80MPH winds again took it on the chin.
If you can live with a 500Watt power rating (that most in the UK do anyway),I still stand by my original findings and say its the best performing Omi on the market.
My friend 4040 in California has just fitted a Sirio Gainmaster in a large tree and with modest power is working the world on SSB......check his videos on Youtube.........All I can say it was a good investment for me and i'm looking forward to this years Sporadic "E" in the summertime......Dave
oggy ive seen all your videos on youb tube and 4040 aswell.
ive actualy heard 4040 out there in dx land. im down in a valley
and some say a top loaded 1/4 wave like the sirio m-400 will
work better for my location. thers say get a 5/8 wave.i dont
believe 1 antenna will work best for all locations but the GM
seems to do well for the people that use it
ive actualy heard 4040 out there in dx land. im down in a valley
and some say a top loaded 1/4 wave like the sirio m-400 will
work better for my location. thers say get a 5/8 wave.i dont
believe 1 antenna will work best for all locations but the GM
seems to do well for the people that use it
hotrod, if you live down in a valley, or cant put your antenna up very high, an astroplane or the old style top one antennas are what you want.
they radiate from the top. the new top one antenna is not the same at all.
as for the top loaded 1/4 wave antenna, there's lots of hype and misinformation going around about this right now.
it seems everyone is jumping on the "top loaded with a cap hat" bandwagon.
yes, its true that a top loaded antenna radiates more signal from the top than a base loaded antenna. but what they dont tell you is that neither one is as good or better than a full sized 1/4 wave antenna.
if they say that it is, they are liars.
LC
they radiate from the top. the new top one antenna is not the same at all.
as for the top loaded 1/4 wave antenna, there's lots of hype and misinformation going around about this right now.
it seems everyone is jumping on the "top loaded with a cap hat" bandwagon.
yes, its true that a top loaded antenna radiates more signal from the top than a base loaded antenna. but what they dont tell you is that neither one is as good or better than a full sized 1/4 wave antenna.
if they say that it is, they are liars.
LC
Loosecannon, I can't argue your claim technically, but I think you're right a full length 1/4 wave radiator should perform as good or better in all aspects with RX and TX compared to a shortened 1/4 wave...even including a top hat or should that be the other way around.
However, twice I've replaced the top of my Top One antenna with a full length radiator and I can only sense a difference that is in favor of the Top Hat performing a bit better. I can't state that the signals were the big difference however, I think most of what I perceived was more of an audio difference. That said however, I did not have the antennas side by side as I often do, so it was just and impression I got during on-air testing. One day I would like to have to AstroPlanes up side-by-side with one having a full length radiator, and really compare what I think I noticed as a real difference.
Even my bandwidth curves for each showed similar results. I go to the trouble to do these reports just so I have some record of the results associated with any change in time, coax, mount, or design for the antenna itself. After doing my reports I usually monitor the on-air results and record some results and then I look back at my record and try and see if it suggest any difference that might support my on-air tests.
Among other things, I hear similar claims such as yours that are somewhat categorical regarding how the Top Hat compares to a full length radiator, and I wonder how that is determined.
Can you describe how you determined your claim Loosecannon? I'm truly interested in how other's perceive their ideas. When thoughtful folks respond to such a question, I often learn something important for my own thinking.
However, twice I've replaced the top of my Top One antenna with a full length radiator and I can only sense a difference that is in favor of the Top Hat performing a bit better. I can't state that the signals were the big difference however, I think most of what I perceived was more of an audio difference. That said however, I did not have the antennas side by side as I often do, so it was just and impression I got during on-air testing. One day I would like to have to AstroPlanes up side-by-side with one having a full length radiator, and really compare what I think I noticed as a real difference.
Even my bandwidth curves for each showed similar results. I go to the trouble to do these reports just so I have some record of the results associated with any change in time, coax, mount, or design for the antenna itself. After doing my reports I usually monitor the on-air results and record some results and then I look back at my record and try and see if it suggest any difference that might support my on-air tests.
Among other things, I hear similar claims such as yours that are somewhat categorical regarding how the Top Hat compares to a full length radiator, and I wonder how that is determined.
Can you describe how you determined your claim Loosecannon? I'm truly interested in how other's perceive their ideas. When thoughtful folks respond to such a question, I often learn something important for my own thinking.
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marconi, if you still have a link to the astroplane patent i sure would appreciate it if you could post it for me. i seem to have lost it and cant seem to get there.
like you, i refer back to that patent sheet now and again because of the great info from herbert blease.
from what i remember him saying about the cap hat vs. the full size radiator, the difference was in the bandwidth.
this didnt seem to be the case in your testing. interesting.
i find it useful to re-read things i have already read, because as i learn, i find things i didnt see before.
im hoping this will happen again with the astroplane patent.
hope you know that your testing efforts are appreciated. you must be tired as heck of climbing ladders@ LOL
LC
like you, i refer back to that patent sheet now and again because of the great info from herbert blease.
from what i remember him saying about the cap hat vs. the full size radiator, the difference was in the bandwidth.
this didnt seem to be the case in your testing. interesting.
i find it useful to re-read things i have already read, because as i learn, i find things i didnt see before.
im hoping this will happen again with the astroplane patent.
hope you know that your testing efforts are appreciated. you must be tired as heck of climbing ladders@ LOL
LC
is this the claim you are talking about marconi?
if so, my point was about antennas that have loading coils. any antenna with a loading coil is not as efficient as its full size counterpart.
now, if we are talking about a full sized 1/4 wave vertical radiator, vs. a vertical radiator with a cap hat on it that made it into a 1/4 wave radiator; then my answer is i dont know.
that is the main reason i want to read the astroplane patent sheet again.
LC
heres the astroplane and starduster patents.
United States Patent: 3587109
United States Patent: 4208662
United States Patent: 3587109
United States Patent: 4208662
thank you bob!
here are the parts i am getting my opinions from:
"Because principal radiation occurs between level B and the level of the crossed conductors, if a larger band width is desired, portion 47 may be increased in length and crossed conductors 48 and 50 reduced in length or eliminated to give the same effective wavelength, i.e., one-fourth wavelength."
47 is the upper vertical member, 48 and 50 are the capacity hat.
here is a part that i just saw that seems like it might contradict what the previous statement said:
"demonstrating that the antenna is effective where the quarter wavelength components approximate one-quarter wavelength in electrical length. This is especially so when the conductor 46 is one-quarter wavelength, for the efficiency drops somewhat for a broader band when the conductor 46 is capacitively loaded, as by the crossed conductors 48 and 50."
to me, this last statement says that when the upper radiator is capacitively loaded, the efficiency drops, in favor of a broader bandwidth.
i really think that avanti used a 4 foot vertical member with a cap hat so that they could get an extra 4 feet of height from the mast.
we must remember that the reason for the design of this antenna was precisely because of the height limit imposed on CB antennas.
anyway, herbert does say that when a cap hat is substituted for a full size 1/4 wave vertical radiator, the efficiency dropped.
thats the part that is most important to me.
LC
here are the parts i am getting my opinions from:
"Because principal radiation occurs between level B and the level of the crossed conductors, if a larger band width is desired, portion 47 may be increased in length and crossed conductors 48 and 50 reduced in length or eliminated to give the same effective wavelength, i.e., one-fourth wavelength."
47 is the upper vertical member, 48 and 50 are the capacity hat.
here is a part that i just saw that seems like it might contradict what the previous statement said:
"demonstrating that the antenna is effective where the quarter wavelength components approximate one-quarter wavelength in electrical length. This is especially so when the conductor 46 is one-quarter wavelength, for the efficiency drops somewhat for a broader band when the conductor 46 is capacitively loaded, as by the crossed conductors 48 and 50."
to me, this last statement says that when the upper radiator is capacitively loaded, the efficiency drops, in favor of a broader bandwidth.
i really think that avanti used a 4 foot vertical member with a cap hat so that they could get an extra 4 feet of height from the mast.
we must remember that the reason for the design of this antenna was precisely because of the height limit imposed on CB antennas.
anyway, herbert does say that when a cap hat is substituted for a full size 1/4 wave vertical radiator, the efficiency dropped.
thats the part that is most important to me.
LC
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