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Old October 7th 03, 09:21 PM
eclip01
 
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Default Repeater antenna help needed...

I am hoping someone can give me some ideas on
this. Thanks in advance for any help you might have.
I am trying this with a Hamtronics REP200 Repeater.
I currently have two ringo, two meter antenna's spaced
50 feet apart vertically and fed with RG213. I have
put these one under the other as suggested by the
repeater mfg and I can't get them to work properly.
I have tried rcv on top and xmt on bottom and the
other way around with little success. I have a bad
de-sense problem either way. I have tried to find
a "sweet spot" and I can find several but none that
are satisfactory. I have been told ringo's are not
good antenna's to try this with because of the fact
they send rf back down the feedline because of the
ring and no radials. I am no antenna expert, but I
am inclined to buy into this. I know the easy way would
be use a duplexer, but I am not into spending a thousand
bucks plus to buy one. I have tried ebay and ended
up with four pieces of junk, so I give up on that.
Anyone have an idea of what kind of antenna's I
would be sucessful with? Also as a side note the
repeater was just in to Hamtronics and got a clean
bill of health, so it is not a repeater problem.
PSYes, I have my coax seperated the whole way
from repeater to the ants.


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Old October 8th 03, 12:59 AM
Ralph Mowery
 
Posts: n/a
Default


I am hoping someone can give me some ideas on
this. Thanks in advance for any help you might have.
I am trying this with a Hamtronics REP200 Repeater.
I currently have two ringo, two meter antenna's spaced
50 feet apart vertically and fed with RG213. I have
put these one under the other as suggested by the
repeater mfg and I can't get them to work properly.
I have tried rcv on top and xmt on bottom and the
other way around with little success. I have a bad
de-sense problem either way. I have tried to find
a "sweet spot" and I can find several but none that
are satisfactory. I have been told ringo's are not
good antenna's to try this with because of the fact
they send rf back down the feedline because of the
ring and no radials. I am no antenna expert, but I
am inclined to buy into this. I know the easy way would
be use a duplexer, but I am not into spending a thousand
bucks plus to buy one. I have tried ebay and ended
up with four pieces of junk, so I give up on that.
Anyone have an idea of what kind of antenna's I
would be sucessful with? Also as a side note the
repeater was just in to Hamtronics and got a clean
bill of health, so it is not a repeater problem.
PSYes, I have my coax seperated the whole way
from repeater to the ants.


Get rid of the single shielded coax first. You are getting lots of desense
from that alone, especially where the coax passes the lower antenna. Use
some 70 ohm catv hardline if you to but make sure it is coated so that the
bare shield does not rub on the tower. I have seen where even a 3 foot
piece of single shielded coax in a duplex system will cause some desense.
You will need more than 50 feet for the seperation. Then get rid of the
ringos and get a good antenna. The only way to have a good two meter
repeater is to use a duplexer or have a very tall tower and run one antenna
up about 50 feet or more and the other one down about 50 feet with the
repeater in the middle. Usually the antenna system/duplexer will cost way
more than the radio equipment.




  #3   Report Post  
Old October 8th 03, 12:59 AM
Ralph Mowery
 
Posts: n/a
Default


I am hoping someone can give me some ideas on
this. Thanks in advance for any help you might have.
I am trying this with a Hamtronics REP200 Repeater.
I currently have two ringo, two meter antenna's spaced
50 feet apart vertically and fed with RG213. I have
put these one under the other as suggested by the
repeater mfg and I can't get them to work properly.
I have tried rcv on top and xmt on bottom and the
other way around with little success. I have a bad
de-sense problem either way. I have tried to find
a "sweet spot" and I can find several but none that
are satisfactory. I have been told ringo's are not
good antenna's to try this with because of the fact
they send rf back down the feedline because of the
ring and no radials. I am no antenna expert, but I
am inclined to buy into this. I know the easy way would
be use a duplexer, but I am not into spending a thousand
bucks plus to buy one. I have tried ebay and ended
up with four pieces of junk, so I give up on that.
Anyone have an idea of what kind of antenna's I
would be sucessful with? Also as a side note the
repeater was just in to Hamtronics and got a clean
bill of health, so it is not a repeater problem.
PSYes, I have my coax seperated the whole way
from repeater to the ants.


Get rid of the single shielded coax first. You are getting lots of desense
from that alone, especially where the coax passes the lower antenna. Use
some 70 ohm catv hardline if you to but make sure it is coated so that the
bare shield does not rub on the tower. I have seen where even a 3 foot
piece of single shielded coax in a duplex system will cause some desense.
You will need more than 50 feet for the seperation. Then get rid of the
ringos and get a good antenna. The only way to have a good two meter
repeater is to use a duplexer or have a very tall tower and run one antenna
up about 50 feet or more and the other one down about 50 feet with the
repeater in the middle. Usually the antenna system/duplexer will cost way
more than the radio equipment.




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