heya folks....

got a general questions about antennas. please excuse my ignorance but i am
new to this hobby. when we were kids my dad had a small base station set up
to an antron 100 antenna and i remember being able to talk to school friends
whose fathers had base stations miles and miles across town. i recently
inherited this exact same antenna, set it up, and it does not seem to be
able to pull in anything over about a mile. can an antenna go "out of tune"
so to speak? i hooked up my cheapo radio shack whip to the same rig and it
worked wayyyyy better. any advice? thanks in advance!

Jeff Shirilla wrote:
heya folks....

got a general questions about antennas. please excuse my ignorance but i am
new to this hobby. when we were kids my dad had a small base station set up
to an antron 100 antenna and i remember being able to talk to school friends
whose fathers had base stations miles and miles across town. i recently
inherited this exact same antenna, set it up, and it does not seem to be
able to pull in anything over about a mile. can an antenna go "out of tune"
so to speak? i hooked up my cheapo radio shack whip to the same rig and it
worked wayyyyy better. any advice? thanks in advance!

Sure it can be out of tune. If it is the same antenna it now has a few
more years of corrosion on it, so start by taking it down, disassembling
it, and clean every electrical connection. Check the coax you used for a
shorted connector and for continuity or lack of continuity between the
center conductor and the shield. Borrow an swr meter, and make any
adjustments necessary to flatten the reflected power around channel 20.
It should work.

hey gary...

thanks for the reply. i will indeed take it down tomorrow and clean the
electrical connections. my dad kept it pretty clean, though... it
looked really good when i got it. the coax cable is brand new so i don'
think that's the problem. i do have an swr meter, but i just can't
figure out how to use it. the instructions that came with it from radio
shack are pretty cryptic. it says for whips you need to clip off part
of it in 1/4 inch sections to tune it. how do you make adjustments to a
large 3-section antenna? thanks!

jj_sutton76 wrote:

hey gary...

thanks for the reply. i will indeed take it down tomorrow and clean the
electrical connections. my dad kept it pretty clean, though... it
looked really good when i got it. the coax cable is brand new so i don'
think that's the problem. i do have an swr meter, but i just can't
figure out how to use it. the instructions that came with it from radio
shack are pretty cryptic. it says for whips you need to clip off part
of it in 1/4 inch sections to tune it. how do you make adjustments to a
large 3-section antenna? thanks!



HI, don't assume the coax is good even if it is new. Check the center
to center, ground to ground and center to ground
with an ohm meter.
Getting new bad coax does happen!!!
Also, when you tried the whip, did you use the same coax?? If so, then
the coax might be OK.
73, Jack

Hey Jack! When checking the coax with the ohm meter as you described,
what sort of a reading shoud you get, and I suppose you should set it
to DC, but at what voltage? I know these are basic questions, but I am
sure I am not the only one who is unsure. Thanks for the reply in
advance! Have a great week! Jon.

Jon,
When checking a coax with an ohm meter. With the coax disconnected on
both ends, measure from shield to ground. This must be an infinity
reading. Now measure the center conductor end to end. This shouldn't be
over a couple ohms at the most. The same for the shield measurement. If
you have a dummy load, connect it to one end and you should read around
52 ohms with the meter. It's best to do that from both ends to ensure
the connectors are good. The only way better to test is with either a
megger or a TDR time Domain Reflectometer.
If you have you atenna connected, you'll find that with most fiberglass
base antennas, you'll have a reading from 40 - 150 ohms do to the
tuning curcuit inside the antenna.
I hope this helps a little.....
73 de Dungeon Master

"Jon L" wrote in message
oups.com...
Hey Jack! When checking the coax with the ohm meter as you described,
what sort of a reading shoud you get, and I suppose you should set it
to DC, but at what voltage? I know these are basic questions, but I am
sure I am not the only one who is unsure. Thanks for the reply in
advance! Have a great week! Jon.

Set the meter on ohms. You should get infinity between the center conductor
and ground. You should get a reading very close to zero when checking ground
to ground or center to center.
On your previous post on swr meter use, place in line close to radio. Place
switch to for, key mic and adjust to where it says cal, the switch it to
ref. That will give you your swr reading.

jj_sutton76 wrote:
hey gary...

thanks for the reply. i will indeed take it down tomorrow and clean the
electrical connections. my dad kept it pretty clean, though... it
looked really good when i got it. the coax cable is brand new so i don'
think that's the problem. i do have an swr meter, but i just can't
figure out how to use it. the instructions that came with it from radio
shack are pretty cryptic. it says for whips you need to clip off part
of it in 1/4 inch sections to tune it. how do you make adjustments to a
large 3-section antenna? thanks!

Just say 'No" to clipp;ing anything until you locate the resonant
frequency of the antenna or have a good idea where it is on the
spectrum. The higher the frequency, the shorter the antenna needs to be,
hence those stubby little things on police cars because they are
operating at very high frequency. If you are shooting for Channel 19 for
example, it is 27.185 MHz. If the antenna swr is flat at 28 MHz, then th
antenna is too short and needs to be lengthened. If the swr is flat at
27 MHz, then the antenna is too long and needs to be shortened.
Sometimes it can be hard to add stuff back on, so be careful about
cutting anything until you are certain.

Hello Jeff:

I haven't ever heard of a Anton 100 Antenna. But I have heard of a
Antron A99 Antenna.

I have seen where the coax has come lose from the matching coil inside
the bottom fiberglass section in a few rare cases.

If there is no continuity (less that a few ohms of resistance) between
the antennas SO-239 connector, center and outside of the connector,
there is a good chance something has come lose or is even burned up.

But I think new Antron A99 Antennas are only 60 dollars.

Good luck.

Jay in the Mojave

Jeff Shirilla wrote:

heya folks....

got a general questions about antennas. please excuse my ignorance but i am
new to this hobby. when we were kids my dad had a small base station set up
to an antron 100 antenna and i remember being able to talk to school friends
whose fathers had base stations miles and miles across town. i recently
inherited this exact same antenna, set it up, and it does not seem to be
able to pull in anything over about a mile. can an antenna go "out of tune"
so to speak? i hooked up my cheapo radio shack whip to the same rig and it
worked wayyyyy better. any advice? thanks in advance!