On Jan 4, 2:39*am, "Ron Hinds" wrote:
Hi - I'm an amateur radio newbie - don't even have a license yet (taking the
Technician exam 1/15). I have a Kenwood TH-F6A and I'm looking for an
antenna for use from home. This looks like a good one - and it's in my price
range ;-) I'm wondering what you experts think of it for a beginner?

http://www.diamondantenna.net/d130j.html

Also, I thought this might make a good mobile antenna. But the instructions
say don't use a magnetic mount. I'm really not interested in any kind of
permanent mount. Why do they say not to use a magnetic mount?

http://www.diamondantenna.net/d220.html

Thanks in advance for taking the time to answer.

Richard is providing a lot more info than me, but the reality is this:
5 watts is not going to do all that great. Your mileage may vary, but
a lot of that power will be eaten up by feedline losses.

Also, bear in mind that a multi band antenna is generally a compromise
on every band it works on.

And finally, a hundred bucks plus shipping is a ripoff for that
antenna in terms of performance. On 2 meters, 220, and 440 a jpole you
could make out of old curtain rods or scrap conduit for ZERO will work
as well or better.

Also, if you make antennas...do not just clone something. 75% of jpole
projects start with copper tubing you have to purchase. Nothing wrong
with that, but the reality is anything metal you can make long enough
will likely work fine. Most people who publish web how to's on Jpole
antennas are copying old designs. Designs get set in the mud and dry
out to the point that noobs get a mindset that nothing else can work
on account of seeing so much of the same thing.

A hundred bucks would go a long way toward some high quality feedline.
Save the money and build an antenna.

Dave

"Dave Smirkenberg" wrote in message
...

A hundred bucks would go a long way toward some high quality feedline.
Save the money and build an antenna.

Dave

Hi Dave,

Thanks for your comments. On the subject of feed line - which of these would
be better:

RG-8X
RG-8/U
RG-213/U

Thanks again for the reply.

- Ron

Ron Hinds wrote:
"Dave Smirkenberg" wrote in message
...

A hundred bucks would go a long way toward some high quality feedline.
Save the money and build an antenna.

Dave

Hi Dave,

Thanks for your comments. On the subject of feed line - which of these would
be better:

RG-8X
RG-8/U
RG-213/U

Thanks again for the reply.

- Ron




RG-213 and RG-8 (both of which standards are actually obsolete, so
you're buying RG-213 "type" cables) are basically the same.. roughly
0.4" in diameter, solid polyethylene dielectric, AWG13 inner conductor.

RG-8X is a smaller diameter foam dielectric cable which will have higher
loss (because the conductors are physically smaller, so IR losses are
higher).

There are tons and tons of other cables that may be better or worse for
your application.

Are you looking for something for VHF and up? In that case, the foam
dielectrics tend to be lower loss than the solid dielectric. foam
dielectric 75 ohm coax (as used in cable TV systems) is pretty good from
a loss standpoint at VHF and UHF, although you need to check the exact
type (there are some pretty bad 75 ohm coaxes out there, too).

Do you care about exposure to the elements?
Does it need to be flexible?

Are you transmitting through it (e.g. is power handling important?)

"Jim Lux" wrote in message
...
RG-213 and RG-8 (both of which standards are actually obsolete, so you're
buying RG-213 "type" cables) are basically the same.. roughly 0.4" in
diameter, solid polyethylene dielectric, AWG13 inner conductor.

RG-8X is a smaller diameter foam dielectric cable which will have higher
loss (because the conductors are physically smaller, so IR losses are
higher).

Then of the three I mentioned, the RG-8/U would be best?

There are tons and tons of other cables that may be better or worse for
your application.

Are you looking for something for VHF and up? In that case, the foam
dielectrics tend to be lower loss than the solid dielectric. foam
dielectric 75 ohm coax (as used in cable TV systems) is pretty good from a
loss standpoint at VHF and UHF, although you need to check the exact type
(there are some pretty bad 75 ohm coaxes out there, too).

Yes, I am mostly interested in 2m, 1.25m, amd 70cm at the moment. Most
cables I've seen - in my admittedly brief exposure - have been 50 ohm.
Wouldn't 75 ohm cause more loss?

Do you care about exposure to the elements?

Yes, as it will be running from a roof antenna to the house. It is on the
north side of the building though, so the majority of it would not be
exposed to the sun.

Does it need to be flexible?

Somewhat. Once in place it won't be moved around much, if at all.

Are you transmitting through it (e.g. is power handling important?)

I hope to be ;-) I'm taking the Technician Class test Saturday! As for power
handling, all I have at the moment is a 5 watt max handheld. I am interested
in building a 50-100 watt power amp for it, though. You wouldn't happen to
know where I could find a schematic for such an animal, would you? Thanks so
much for your reply Jim!

Ron Hinds wrote:
Then of the three I mentioned, the RG-8/U would be best?

I think you have completely lost sight of what you are doing. The radio in
question is a handheld device, aka a "Handie-Talkie" or H/T. It is designed
to work with the whip antenna that comes with it.

It may not get better reception or transmission with a larger antenna,
and may actually do worse. The front end of the radio is not designed to
handle large signals and it could easily overload and hear nothing.

Obvioulsy an outside antenna is needed if you are inside metal or poured
concrete (due to the steel reinforcing bars) walls or in a car. In a wooden
or plasterboard house, you may not get a lot of improvement nor need it.

You might think that a high gain antenna will improve your reception, but
if there is a close station or repeater it will just blank out. It does not
have to a ham transmitter, paging, VHF (fire/EMS, etc) will wipe out 2m,
and UHF can disappear under a GMRS or land mobile system.

If you live out in the woods, then a decent outside antenna will help and
a random wire or dipole will help with HF reception. In a big city, the
ferrite bar (up to 7mHz) will be a noise magnet and you many not even be able
to receive anything at all.

As for coax, good quality RG-6 coax will do fine, and you can get it almost
anywhere. Make sure to use high quality COMPRESSION connectors and adaptors.
The radio uses an SMA connector so you will need to get an SMA to F to connect
it to the coax and the antenna will have a PL-259 (aka UHF) or "N" connector
on it so you will need to get the connectors from a specialty shop.

You also want to get an external speaker and microphone as if you connect
up a coax to it, you will destroy the radio. The stress on the antenna
connector will cause it to break, or crack the circuit board it is connected
to. If you epxect to hand hold the radio and talk on it, something stiff
such as RG/213 may not last out a day of activity. :-(

Geoff.

--
Geoffrey S. Mendelson N3OWJ/4X1GM
Those who cannot remember the past are condemned to misquote it.

On Jan 12, 1:49*am, "Geoffrey S. Mendelson"
wrote:
Ron Hinds wrote:
Then of the three I mentioned, the RG-8/U would be best?

I think you have completely lost sight of what you are doing. The radio in
question is a handheld device, aka a "Handie-Talkie" or H/T. It is designed
to work with the whip antenna that comes with it.

It may not get better reception or transmission with a larger antenna,
and may actually do worse. The front end of the radio is not designed to
handle large signals and it could easily overload and hear nothing.

Obvioulsy an outside antenna is needed if you are inside metal or poured
concrete (due to the steel reinforcing bars) walls or in a car. In a wooden
or plasterboard house, you may not get a lot of improvement nor need it.

You might think that a high gain antenna will improve your reception, but
if there is a close station or repeater it will just blank out. It does not
have to a ham transmitter, paging, VHF (fire/EMS, etc) will wipe out 2m,
and UHF can disappear under a GMRS or land mobile system.

If you live out in the woods, then a decent outside antenna will help and
a random wire or dipole will help with HF reception. In a big city, the
ferrite bar (up to 7mHz) will be a noise magnet and you many not even be able
to receive anything at all.

As for coax, good quality RG-6 coax will do fine, and you can get it almost
anywhere. Make sure to use high quality COMPRESSION connectors and adaptors.
The radio uses an SMA connector so you will need to get an SMA to F to connect
it to the coax and the antenna will have a PL-259 (aka UHF) or "N" connector
on it so you will need to get the connectors from a specialty shop.

You also want to get an external speaker and microphone as if you connect
up a coax to it, you will destroy the radio. The stress on the antenna
connector will cause it to break, or crack the circuit board it is connected
to. If you epxect to hand hold the radio and talk on it, something stiff
such as RG/213 may not last out a day of activity. :-(

Geoff.

--
Geoffrey S. Mendelson N3OWJ/4X1GM
Those who cannot remember the past are condemned to misquote it.

I always "pigtail" fat, stiff antenna cables if I'm using them on an
HT. A pigtail is a short length of a small. lightweight cable that's
sufficiently flexible to put no great strain on the HT connector.
Since it's short, you don't lose significant signals. Some folks will
claim that losses in the extra connectors and adapters are a big
problem. Nope, not if they're properly made and installed.

"Sal"

"Geoffrey S. Mendelson" wrote in message
...
Ron Hinds wrote:
Then of the three I mentioned, the RG-8/U would be best?

I think you have completely lost sight of what you are doing. The radio in
question is a handheld device, aka a "Handie-Talkie" or H/T. It is
designed
to work with the whip antenna that comes with it.

It may not get better reception or transmission with a larger antenna,
and may actually do worse. The front end of the radio is not designed to
handle large signals and it could easily overload and hear nothing.

Obvioulsy an outside antenna is needed if you are inside metal or poured
concrete (due to the steel reinforcing bars) walls or in a car. In a
wooden
or plasterboard house, you may not get a lot of improvement nor need it.

You might think that a high gain antenna will improve your reception, but
if there is a close station or repeater it will just blank out. It does
not
have to a ham transmitter, paging, VHF (fire/EMS, etc) will wipe out 2m,
and UHF can disappear under a GMRS or land mobile system.

If you live out in the woods, then a decent outside antenna will help and
a random wire or dipole will help with HF reception. In a big city, the
ferrite bar (up to 7mHz) will be a noise magnet and you many not even be
able
to receive anything at all.

As for coax, good quality RG-6 coax will do fine, and you can get it
almost
anywhere. Make sure to use high quality COMPRESSION connectors and
adaptors.
The radio uses an SMA connector so you will need to get an SMA to F to
connect
it to the coax and the antenna will have a PL-259 (aka UHF) or "N"
connector
on it so you will need to get the connectors from a specialty shop.

You also want to get an external speaker and microphone as if you connect
up a coax to it, you will destroy the radio. The stress on the antenna
connector will cause it to break, or crack the circuit board it is
connected
to. If you epxect to hand hold the radio and talk on it, something stiff
such as RG/213 may not last out a day of activity. :-(

Geoff.

--
Geoffrey S. Mendelson N3OWJ/4X1GM
Those who cannot remember the past are condemned to misquote it.

Thank you for the excellent suggestions, Geoff! I live in the boonies - the
nearest repeater is about 15 miles away and no line of sight with it - at
least not at ground level. All of the others are considerably farther away
and no line of sight with them, either (lots of mountains here). I already
have a short SMA adapter cable for my mobile antenna, and a speaker/mic too.

On Jan 8, 6:05*am, Dave Smirkenberg wrote:
On Jan 4, 2:39*am, "Ron Hinds" wrote:

Hi - I'm an amateur radio newbie - don't even have a license yet (taking the
Technician exam 1/15). I have a Kenwood TH-F6A and I'm looking for an
antenna for use from home. This looks like a good one - and it's in my price
range ;-) I'm wondering what you experts think of it for a beginner?

http://www.diamondantenna.net/d130j.html

Also, I thought this might make a good mobile antenna. But the instructions
say don't use a magnetic mount. I'm really not interested in any kind of
permanent mount. Why do they say not to use a magnetic mount?

http://www.diamondantenna.net/d220.html

Thanks in advance for taking the time to answer.

Richard is providing a lot more info than me, but the reality is this:
5 watts is not going to do all that great. Your mileage may vary, but
a lot of that power will be eaten up by feedline losses.

Also, bear in mind that a multi band antenna is generally a compromise
on every band it works on.

And finally, a hundred bucks plus shipping is a ripoff for that
antenna in terms of performance. On 2 meters, 220, and 440 a jpole you
could make out of old curtain rods or scrap conduit for ZERO will work
as well or better.

Also, if you make antennas...do not just clone something. 75% of jpole
projects start with copper tubing you have to purchase. Nothing wrong
with that, but the reality is anything metal you can make long enough
will likely work fine. Most people who publish web how to's on Jpole
antennas are copying old designs. Designs get set in the mud and dry
out to the point that noobs get a mindset that nothing else can work
on account of seeing so much of the same thing.

A hundred bucks would go a long way toward some high quality feedline.
Save the money and build an antenna.

Dave

Amen!

I love to build antennas and I could not do it without some form of
measurement device to determine the characteristics of the in-work
project. I usually go by VSWR and alter the design in various ways
(often slight changes to element lengths) to minimize the VSWR at my
chosen freq. a VHF/UHF VSWR meter can be had for peanuts but a 250-
dollar antenna analyzer will be in your future if you get a case of
Antenna Fever. (Yeah, I have one.) However, as you are just getting
started, try reading this: http://kb6nu.com/no-vhf-swr-meter-no-problem/

I like working in copper pipe at VHF and above. It's very durable and
responds well to a Home Depot propane torch for so-called "sweat
soldering." Copper pipe comes in several grades. The cheapest grade
seems to make antennas that are just fine.

Welcome to the hobby.

"Sal"
KD6VKW