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lmr 400
- Thread starter 2112
- Start date
I'm sure if we all think about the very small loss factors in coax and how it affects our radio experience in HF, we will have to agree that 'Doc is right when he says;
Ol' King is just giving us more of the hardline about Hard Line again. It sounds like when he talks about his experiences on his CB using HL, folks he talks to have to turn down their volume when he talks to them, and then turn the volume back up again in order to hear all the others on the air. I'm sure our ears cannot perceive the actual audio differences within the range of difference we are discussing here. King, I sure would like to know how you measure your claim of better TX/RX using HL over any of the other coax mentioned here?
I had a feed line to my antenna once that was severaly contaminade with water over time and even though I could not produce as big of signal as my neighbors to other buddies, I was still able to communicate. In fact I often heard others better than guys around me. I did not know why at the time, and figured it was my antenna. Much later I tested this line and found out I was only getting a little less than 1/4 watt out to the end of this 100' of RG8X with 4 watts of input. You can do a similar test on your line using a good dummy load. When I discovered this I was amazed that I could hear, and really amazed that I could talk. It was then that I realized that even though there can be big differences in signals we see, it really doesn't take much to communicate over a pretty good range with little signal or not.
You say you can communicate using your I-10K from coast to coast whether DX is working or not. Can you do that down here into the Gulf Coast area of Texas? If you can I sure would like to hook up with you on my I-10K sometime. You let me know when and where and I will make it a point to meet you there. If you can do that I will never again question anything you say.
Marconi
Ol' King is just giving us more of the hardline about Hard Line again. It sounds like when he talks about his experiences on his CB using HL, folks he talks to have to turn down their volume when he talks to them, and then turn the volume back up again in order to hear all the others on the air. I'm sure our ears cannot perceive the actual audio differences within the range of difference we are discussing here. King, I sure would like to know how you measure your claim of better TX/RX using HL over any of the other coax mentioned here?
I had a feed line to my antenna once that was severaly contaminade with water over time and even though I could not produce as big of signal as my neighbors to other buddies, I was still able to communicate. In fact I often heard others better than guys around me. I did not know why at the time, and figured it was my antenna. Much later I tested this line and found out I was only getting a little less than 1/4 watt out to the end of this 100' of RG8X with 4 watts of input. You can do a similar test on your line using a good dummy load. When I discovered this I was amazed that I could hear, and really amazed that I could talk. It was then that I realized that even though there can be big differences in signals we see, it really doesn't take much to communicate over a pretty good range with little signal or not.
You say you can communicate using your I-10K from coast to coast whether DX is working or not. Can you do that down here into the Gulf Coast area of Texas? If you can I sure would like to hook up with you on my I-10K sometime. You let me know when and where and I will make it a point to meet you there. If you can do that I will never again question anything you say.
Marconi
All I have to say about that is
:roll: We have all heard kingcobra bestow the virtues of the heliax he uses. It IS heliax BTW not hardline.Hardline is rigid and looks like solid c o p p e r pipe.You have to use special fittings to make corner bends etc. Anyway, nobody and I mean NOBODY is going to see ANY kind of differance on HF ,and I include CB,when going from RG-8 cable to any size heliax cable.If the heliax had absouletly zero loss the differance gained could only be the normal loss in the RG-8 type cable and for CB that is usually around 1 dB. RG-8 or RG-213 is speced at 1.3 dB loss at 50 MHz so even if heliax was perfect then you would only see an improvement of 1.3 dB/100 ft. but in the real world LDF5-50 which is 7/8 inch heliax has a loss at 50 MHz of 0.25 dB so the net gain would be 1.05dB.Not noticable.VHF and UHF are a differant matter. I have worked on systems up to 1 GHz and could only measure a slight improvement in changing from RG-213 to LDF4-50,1/2 inch heliax, on VHF systems at 172.68 MHz with a run of just over 100 feet.No offence King but the only one you are really fooling is yourself with wild claims of the GREAT benefits of heliax on HF and the need for LDF-7 or greater for VHF/UHF.Unless you have a run of several hundred feet then LDF4 is all you need.Hell that is all we needed in the broadcast business for critical program links on 455 MHz and for up to 100 feet on 960 MHz. before we switched to 7/8 inch.We used LDF7-50 on the FM broadcast band with up to 10Kw transmitters and that was plenty.I saw one post where you said you paid $300 for connectors for your heliax and I am trying to find a polite way to say this but it just is not working so please try not to take offense but, you must have more money than brains.I don't want to start an arguement but I see the facts as the real world sees them.I've used heliax and hardline for too many years in too many installations from 960KHz to 960 MHZ to be fooled. Perhaps if I had that kind of money tied up in cable I could convince myself of some things too.
i had not realised i could do so with my set up
untill a neighbor of mine bought a I-10K from me
he set it up maybe 2 air miles from me
he is using at best a cobra 200 GTL with LMR400 with his antenna at a height of 32 or 35 feet at base of antenna
he told me how he was able to talk to a friend regularly in calif
not using a beam (he doesnt have one) but the Intercreptor I-10K
i too was like whatever
however i tried it as well and worked
there is a slight trick though
in that it usally is doable at 2 to 5 am EST and must be on a ultra quiet channel
so i tried it with him a few times and worked
can also be in part our location
in that i am surrounded by water on 3 sides
(water to east,west and south)
difference in his set up and mine is
my antenna is 52 or 54 ft to base of I-10K
i am using LDF5-50A
i am using IC-7000
i am using SM-20 desk mike
has been about 8 months since i did so last time
has been a month since i have had my voice back
and still not used my gear much and will not till temps stay in
60's or higher(where i need not worry about bronkitis i had that kept me home 11 weeks and unable to talk easily for 4 or 5 more weeks)
i still say
feedline is extremly importent in the set up (since is part of antenna) and although LMR400 is good for general CB use
in my eyes (and to eaches own)
a system is only as good as its weekest link
and once past the initial difficulty in working with hardline
and if you can afford hardline
then hardline will dance circles round LMR400
if you want good LMR stuff then there is LMR900 and LMR1200
but at that point i still opt for Andrews Heliax 7/8 or better
coax-feedline
actually
ladder-line has many advantages even over hardline
but there are many dis advantages as well
but if someone wants exellent and easy to work with feedline
ladder-line is quite hard to beat
be it performace or price
one of these days i might even get around to getting and using linears....so far...has been no need to
i am tempted to get the navy linear that i have had in storage for decades....just draws way too much power
untill a neighbor of mine bought a I-10K from me
he set it up maybe 2 air miles from me
he is using at best a cobra 200 GTL with LMR400 with his antenna at a height of 32 or 35 feet at base of antenna
he told me how he was able to talk to a friend regularly in calif
not using a beam (he doesnt have one) but the Intercreptor I-10K
i too was like whatever
however i tried it as well and worked
there is a slight trick though
in that it usally is doable at 2 to 5 am EST and must be on a ultra quiet channel
so i tried it with him a few times and worked
can also be in part our location
in that i am surrounded by water on 3 sides
(water to east,west and south)
difference in his set up and mine is
my antenna is 52 or 54 ft to base of I-10K
i am using LDF5-50A
i am using IC-7000
i am using SM-20 desk mike
has been about 8 months since i did so last time
has been a month since i have had my voice back
and still not used my gear much and will not till temps stay in
60's or higher(where i need not worry about bronkitis i had that kept me home 11 weeks and unable to talk easily for 4 or 5 more weeks)
i still say
feedline is extremly importent in the set up (since is part of antenna) and although LMR400 is good for general CB use
in my eyes (and to eaches own)
a system is only as good as its weekest link
and once past the initial difficulty in working with hardline
and if you can afford hardline
then hardline will dance circles round LMR400
if you want good LMR stuff then there is LMR900 and LMR1200
but at that point i still opt for Andrews Heliax 7/8 or better
coax-feedline
actually
ladder-line has many advantages even over hardline
but there are many dis advantages as well
but if someone wants exellent and easy to work with feedline
ladder-line is quite hard to beat
be it performace or price
one of these days i might even get around to getting and using linears....so far...has been no need to
i am tempted to get the navy linear that i have had in storage for decades....just draws way too much power
It is a band opening allowing that.There is DX happening. I used to work England and Ireland after midnight local time here on 11m.Sometimes I could work England to the east and Australia and Japan to the west at the same time.The signals were extremly weak but 100% readable.I would have sworn the band was dead at the time.Sometimes it would last for a few hours.
Very true but the weakest link is not necessarily too weak for the purpose.Often the antenna matching system will have as much or more loss than the cable you are feeding it with.
Not on HF it won't. The MAXIMUM differance it can possibly make is the differance in the losses between the two cables and on HF that amounts to around 1 dB per 100 feet when compared to RG-8 or RG-213.Unless you have hundreds of feet or are on V/UHF then it will NOT matter.
even with slight differences/improvement of lack of losses
can still make a significant difference
and was not band openings
i do know what band openings/DX is
can still make a significant difference
and was not band openings
i do know what band openings/DX is
we're talking about .65db. difference between LDF5-50A and LMR400 @ 50mhz. we're talking about nothing, not a damn thing anyone is going to notice or miss one way or the other.
at .65db. of additional line loss of LMR400 with 1.5KW in at the transmitter yields 1.290KW at the antenna, based on line loss difference between the two only........big deal.
based on 1.5KW in at the transmitter end of the feedline:
1500W IN / 1217W OUT @ .90db
1500W IN / 1415W OUT @ .25db.
---------------------------------
1500W IN / 1290W OUT @ .65db.
a difference in the power delivered between the two feedlines of 198W....big deal. so with the cost of 100' of LDF5-50A and those $300.00 connectors you're paying what, another $4.97 per foot for every extra watt of power delivered over and above 1217W and that doesn't include your connectors. it would be cheaper to get another 200W out of an amplifier to overcome the loss. hell, you could operate the amp on the tower at the feedpoint and add a little extra drive from the exciter and still be ahead of the game. no, let's go buy some unnecessarily expensive feedline instead.
this thread is way past ridiculous.
at .65db. of additional line loss of LMR400 with 1.5KW in at the transmitter yields 1.290KW at the antenna, based on line loss difference between the two only........big deal.
based on 1.5KW in at the transmitter end of the feedline:
1500W IN / 1217W OUT @ .90db
1500W IN / 1415W OUT @ .25db.
---------------------------------
1500W IN / 1290W OUT @ .65db.
a difference in the power delivered between the two feedlines of 198W....big deal. so with the cost of 100' of LDF5-50A and those $300.00 connectors you're paying what, another $4.97 per foot for every extra watt of power delivered over and above 1217W and that doesn't include your connectors. it would be cheaper to get another 200W out of an amplifier to overcome the loss. hell, you could operate the amp on the tower at the feedpoint and add a little extra drive from the exciter and still be ahead of the game. no, let's go buy some unnecessarily expensive feedline instead.
this thread is way past ridiculous.
KingCobra_CDX882 said:
Tell me how a slight differance can make a significant differance when we are talking about dB loss? :?
Apparently you don't. Nobody but NOBODY is going to work coast to coast without a band opening except for satellite comms or EME and don't even think you were bouncing your 11m signal off the moon. :roll: The fact you have water on three sides means nothing.It is all land between you and the west coast.I do not ever expect you to change your mind and I certainly am not about to either so I shall resist the temptation to comment further but at least I have facts and the laws of physics on my side. :roll:
and just so you low power operators can get a feel for just how little difference it amounts to let me scale these figures from my last post, the logarithm remains the same.
1500W IN / 1217W OUT @ .90db.
or 150W IN / 121.7W OUT
or 15W IN / 12.17W OUT
or 1.5W IN / 1.217W OUT
1500W IN / 1415W OUT @ .25db.
or 150W IN / 141.5W OUT
or 15W IN / 14.15W OUT
or 1.5W IN / 1.415W OUT
---------------------------------
1500W IN / 1290W OUT @ .65db.
or 150W IN / 129W OUT
or 15W IN / 12.9W OUT
or 1.5W IN / 1.29W OUT
the facts and the laws of physics are fully supported by the mathematics. the numbers and the line loss figures remain the same, only the position of the decimal point changes, that's the beauty of base 10. are you starting to get the picture yet?
sorry but heliax won't magically turn you into a "big strapper".
"Much later I tested this line and found out I was only getting a little less than 1/4 watt out to the end of this 100' of RG8X with 4 watts of input."
you have almost a perfect homebrew 12db. pad there Marconi.
1500W IN / 1217W OUT @ .90db.
or 150W IN / 121.7W OUT
or 15W IN / 12.17W OUT
or 1.5W IN / 1.217W OUT
1500W IN / 1415W OUT @ .25db.
or 150W IN / 141.5W OUT
or 15W IN / 14.15W OUT
or 1.5W IN / 1.415W OUT
---------------------------------
1500W IN / 1290W OUT @ .65db.
or 150W IN / 129W OUT
or 15W IN / 12.9W OUT
or 1.5W IN / 1.29W OUT
the facts and the laws of physics are fully supported by the mathematics. the numbers and the line loss figures remain the same, only the position of the decimal point changes, that's the beauty of base 10. are you starting to get the picture yet?
sorry but heliax won't magically turn you into a "big strapper".
"Much later I tested this line and found out I was only getting a little less than 1/4 watt out to the end of this 100' of RG8X with 4 watts of input."
you have almost a perfect homebrew 12db. pad there Marconi.
here it is...in layman terms
165 feet (from my radio to antenna,may be 175 i forget)
.195 Db loss at 30 mhz LDF6-50A ( is 0.32175 Db loss)
.7 Db loss LMR400 (1.155 Db loss)
means a loss difference of .83325 Db (further loss in using LMR400 verses using LDF5-50A)
difference being .5 Db (for argument sake a half of a DB difference)
.5 at 100 feet equals .85 Db loss
this is 85% of a Db further loss is using LMR400 at same 165 feet
so herefore this is nearly a Db loss (not quite ofcourse..but for the math we will say a Db loss difference)
if one uses same antenna
one uses 100 watts to make said contact
to do same contact with a 1 Db inprovement is a apriecable gain
(it will not get you heard at far greater distances being only a single Db in provement)
but how many of us consider say a Imax2000 compared to say a I-10K and improvement
well ofcourse it is the Interceptor i-10K that is clearly the better antenna.....
the I-10K has about a 3 Db gain advantage over the Imax 2000
do not those using I-10K or the coily or wolf.64 wave a clear advantage over the lower gain Imax2000
ofcourse it is
i simply am going a additional step and gaining nearly a full Db
by using better coax....and in using this coax it also has a lower requirement of wear and tear(or need to fix/replace it)then lesser grade feedline
so now i have taken what would have been a 3 Db gain in use of better antenna and instead picked up another Db and so i now have a 4 Db total improvement
now if memory serves me Jay's I-10K actually has a 3.4 Dbd gain over Imax2000 and add my .83 additional gain..and now i have 4.23 gain improvement (nearly 4and 1/4 Dbd improvement)
all i am saying is
i have taken a further step to fine tune a slightly higher and superior gain of a better antenna system
is it superior to have gain from a linear-amp or from antenna
doing it via antenna is a more solid and continually realised gain
and overall better quality system
now if one wanted to talk amps-linears
then there is yet even more advantages to LDF5-50A
that is it is designed for ability to handle on everyday basis far greater power then LMR400
i (we) do not need to hear how LMR supposedly will handle 10,000 watts (that is rubbish) for LDF5-50A at 30 Mhz is rated for 10,000 watts
it is 3300 watts at same 30 Mhz handling ability for LMR400
so if one used say 1000 watts they are about 30% of max ability...while same 1000 into LDF5-50A is only 10% of max
so with amp-linear (if i ever deside to do so)i will run far less stress into the feedline using the LDF5-50A
there are also better Velocity Factor and this adds slight advantage yet again
am i talking about slight gains and or advantages
yes and no...there are clear and undenyable advantages
does it cost more...is it harder to work with..
yes ofcourse..
why does a A99 or Imax2000 cost so little compared to say a MrCoily antenna or a Interceptor I-10K
are all those who pay much more for those better quaility antennas...where it enables advantages suc as better gain
better build that will hold up to worse weather
where it it have better ears (going from fiberglass to metal)
well if those people are all crazy
then many do not understand or apricate the benifits
those who do understand and apriciate the difference
well those are the ones who typiclly get out better
and are always asked
what are you doing that i am not
now back to LDF5-50A
its center is nearly size of coax many are using
how can a few strands of wire compare to a non stop band of metal (it doesnt)
now i could easily use this for VHF and UHF where most people consider using such feedline
but then for only slight more price and slight more fdifficulty in working with the coax..i find LDF7-50A does far better
(i had thought of going further....but i already had a neighbor..
yes a stupid neighbor.....say in seeing my LDF7-50A which is 2.25 to 2.5 inches thick..he called the cops to say i was steeling cable tv...when cop asked why the neighbor thought so..he pointed to the cop my LDF7-50A
feedline running from second floor out past 3rd floor and up to roof to my beams...the cop laughed saying he(me) had stuff even they(the cops) didnt have......then the cop (who knows me) came down to my work to give me a good laugh)
it seems this post got a bit long...oh well
LMR400 is ok....but is just that..ok to faily good
165 feet (from my radio to antenna,may be 175 i forget)
.195 Db loss at 30 mhz LDF6-50A ( is 0.32175 Db loss)
.7 Db loss LMR400 (1.155 Db loss)
means a loss difference of .83325 Db (further loss in using LMR400 verses using LDF5-50A)
difference being .5 Db (for argument sake a half of a DB difference)
.5 at 100 feet equals .85 Db loss
this is 85% of a Db further loss is using LMR400 at same 165 feet
so herefore this is nearly a Db loss (not quite ofcourse..but for the math we will say a Db loss difference)
if one uses same antenna
one uses 100 watts to make said contact
to do same contact with a 1 Db inprovement is a apriecable gain
(it will not get you heard at far greater distances being only a single Db in provement)
but how many of us consider say a Imax2000 compared to say a I-10K and improvement
well ofcourse it is the Interceptor i-10K that is clearly the better antenna.....
the I-10K has about a 3 Db gain advantage over the Imax 2000
do not those using I-10K or the coily or wolf.64 wave a clear advantage over the lower gain Imax2000
ofcourse it is
i simply am going a additional step and gaining nearly a full Db
by using better coax....and in using this coax it also has a lower requirement of wear and tear(or need to fix/replace it)then lesser grade feedline
so now i have taken what would have been a 3 Db gain in use of better antenna and instead picked up another Db and so i now have a 4 Db total improvement
now if memory serves me Jay's I-10K actually has a 3.4 Dbd gain over Imax2000 and add my .83 additional gain..and now i have 4.23 gain improvement (nearly 4and 1/4 Dbd improvement)
all i am saying is
i have taken a further step to fine tune a slightly higher and superior gain of a better antenna system
is it superior to have gain from a linear-amp or from antenna
doing it via antenna is a more solid and continually realised gain
and overall better quality system
now if one wanted to talk amps-linears
then there is yet even more advantages to LDF5-50A
that is it is designed for ability to handle on everyday basis far greater power then LMR400
i (we) do not need to hear how LMR supposedly will handle 10,000 watts (that is rubbish) for LDF5-50A at 30 Mhz is rated for 10,000 watts
it is 3300 watts at same 30 Mhz handling ability for LMR400
so if one used say 1000 watts they are about 30% of max ability...while same 1000 into LDF5-50A is only 10% of max
so with amp-linear (if i ever deside to do so)i will run far less stress into the feedline using the LDF5-50A
there are also better Velocity Factor and this adds slight advantage yet again
am i talking about slight gains and or advantages
yes and no...there are clear and undenyable advantages
does it cost more...is it harder to work with..
yes ofcourse..
why does a A99 or Imax2000 cost so little compared to say a MrCoily antenna or a Interceptor I-10K
are all those who pay much more for those better quaility antennas...where it enables advantages suc as better gain
better build that will hold up to worse weather
where it it have better ears (going from fiberglass to metal)
well if those people are all crazy
then many do not understand or apricate the benifits
those who do understand and apriciate the difference
well those are the ones who typiclly get out better
and are always asked
what are you doing that i am not
now back to LDF5-50A
its center is nearly size of coax many are using
how can a few strands of wire compare to a non stop band of metal (it doesnt)
now i could easily use this for VHF and UHF where most people consider using such feedline
but then for only slight more price and slight more fdifficulty in working with the coax..i find LDF7-50A does far better
(i had thought of going further....but i already had a neighbor..
yes a stupid neighbor.....say in seeing my LDF7-50A which is 2.25 to 2.5 inches thick..he called the cops to say i was steeling cable tv...when cop asked why the neighbor thought so..he pointed to the cop my LDF7-50A
feedline running from second floor out past 3rd floor and up to roof to my beams...the cop laughed saying he(me) had stuff even they(the cops) didnt have......then the cop (who knows me) came down to my work to give me a good laugh)
it seems this post got a bit long...oh well
LMR400 is ok....but is just that..ok to faily good
"the I-10K has about a 3 Db gain advantage over the Imax 2000"
Jays I10K doesn't have "3.4 Dbd gain over Imax2000........"
are you confused or just having trouble making up your mind?
the Dbd means that the I10K is referenced to a dipole........so which is it, a dipole or the imax2000....LMAO\
LDF5-50A is rated for 7700W @ 10mhz. and 7740W @ 50mhz..
everything from there on down is bullshit.
Jays I10K doesn't have "3.4 Dbd gain over Imax2000........"
are you confused or just having trouble making up your mind?
the Dbd means that the I10K is referenced to a dipole........so which is it, a dipole or the imax2000....LMAO\
LDF5-50A is rated for 7700W @ 10mhz. and 7740W @ 50mhz..
everything from there on down is bullshit.
You lost me at
Where does the .5 dB come into play? Antenna type and selection has NOTHING to do with ANYTHING when comparing the differances between two transmission lines.That only comes into play when comparing the overall improvement to an antenna SYSTEM and comparing IT to the last one. This is NOT what is being discussed here at all and never was.It was about the differance in LMR-400 and heliax.
I know,I know I said I would resist the temptation to comment further but trust me I did resist. I never was any good at holding out for too long.
Where does the .5 dB come into play? Antenna type and selection has NOTHING to do with ANYTHING when comparing the differances between two transmission lines.That only comes into play when comparing the overall improvement to an antenna SYSTEM and comparing IT to the last one. This is NOT what is being discussed here at all and never was.It was about the differance in LMR-400 and heliax.
I know,I know I said I would resist the temptation to comment further but trust me I did resist. I never was any good at holding out for too long.
i was taking a .7Db loss of LMR400 and minising .195 Db loss of LDF5-50A (at 30MHZ)
equaling just over .5 Db additional loss in LMR400 compared to LDF5-50A
equaling just over .5 Db additional loss in LMR400 compared to LDF5-50A