In article ,
Bruce W.1 wrote:

Does anyone make a telescoping HT antenna meant to operate (1/4 wave)
over a broad band of frequencies with marking for those frequencies?

I've seen one or two such on a dealer's table at a local hamfest,
although I'm not sure that they come pre-marked - the package gave
instructions for the number of segments to collapse to achieve
resonance on 220 and 440. I think one was made by ADI and/or Premier
but I can't be sure.

Most HT's can be modified to operate outside the amateur bands, like on
GMRS, MURS, FRS, etc. But I don't like doing this without a proper antenna.

You really shouldn't do it (well, at least, not transmit) even _with_
a proper antenna. Very few, if any amateur-radio HTs are certificated
for transmission on those bands, and using an "opened-up" ham HT to
transmit (even if you have a suitable GMRS license) is a rules
violation which could cost you your amateur ticket.

FRS and GMRS have very strict technical rules about the frequency
accuracy of their oscillators due to the tight inter-channel spacings,
and it's likely that at least some ham HTs are too sloppy in design
(or too poorly calibrated) to hit the frequencies accurately.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

I agree. You run into the same problems that Public Safety radios
have to deal with. That is, trying to operate over a wide range
perhaps 150 -174 MHz with a high power radio. Certainly the 1/4 wave
is the best you can do to avoid shutdown of the radio.

For Dual-band 2m/440 operation and in particular when operating MARS,
a 1/4 wave 144 MHz antenna will provide a more satisfactory load at
UHF as well, although with a compromised pattern on those
frequencies.

One of the most frightening tests I performed with 2m/440 ham
antennas was that they were extremely sharp in bandwidth and resulted
in extreme SWR beyond -+ 2-3 MHz on either band.

Public safety personnel often don't understand how hams can have high
performance dual band antennas and they can't. Some suspiciously
consider a conspiracy. The simple answer lies in the frequency
coordination of the repeater frequencies on both bands, and the
narrow but coincidental sliver of frequencies we use for mobile
operation.

If you have a telescopic whip you are blessed. Carry a tape measure
and chart with you.

Of course there are other issues regarding MURS, GMRS and FRS that
are completely awkward and you might as well carry a real FRS radio
along with a Commercial radio with a bank devoted to the ham bands on
your bat-belt.

I contest the mentality that says you should "open up" a ham radio
for "emergency use only" because you compromise the emergency
situation by not using a radio up to the task. You can use a
"church-key" as a can opener, but if you are truly serious you will
pack a can opener.

Jim, ac6tk


"Dave Platt" wrote in message
...
In article ,
Bruce W.1 wrote:

Does anyone make a telescoping HT antenna meant to operate (1/4
wave)
over a broad band of frequencies with marking for those
frequencies?

I've seen one or two such on a dealer's table at a local hamfest,
although I'm not sure that they come pre-marked - the package gave
instructions for the number of segments to collapse to achieve
resonance on 220 and 440. I think one was made by ADI and/or
Premier
but I can't be sure.

Most HT's can be modified to operate outside the amateur bands,
like on
GMRS, MURS, FRS, etc. But I don't like doing this without a
proper antenna.

You really shouldn't do it (well, at least, not transmit) even
_with_
a proper antenna. Very few, if any amateur-radio HTs are
certificated
for transmission on those bands, and using an "opened-up" ham HT to
transmit (even if you have a suitable GMRS license) is a rules
violation which could cost you your amateur ticket.

FRS and GMRS have very strict technical rules about the frequency
accuracy of their oscillators due to the tight inter-channel
spacings,
and it's likely that at least some ham HTs are too sloppy in design
(or too poorly calibrated) to hit the frequencies accurately.

--
Dave Platt
AE6EO
Hosting the Jade Warrior home page:
http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I
will
boycott any company which has the gall to send me such ads!

I for one take the easy way out on all bands, vhf hf etc.
Use "tuners". At least your protecting whatever rigs ouput
you have. It does'nt speak to efficiency that way, but I get
rather good results with my G6 VHF antenna on all modes and
on MARS freqcys also which are out of the HAM band limits.
HF same thing. MFJ diferential T tuner with roller coil gets
me anywhere I want to go from 3.5 mhz on down to 30 mhz.
Kokomo Joe


************************************************** **
* Ham KH6JF AARS/MARS ABM6JF QCWA WW2 VET WD RADIO *
* Army MARS State Coordinator for Hawaii *
************************************************** **


On Tue, 5 Apr 2005, JB wrote:

I agree. You run into the same problems that Public Safety radios
have to deal with. That is, trying to operate over a wide range
perhaps 150 -174 MHz with a high power radio. Certainly the 1/4 wave
is the best you can do to avoid shutdown of the radio.

For Dual-band 2m/440 operation and in particular when operating MARS,
a 1/4 wave 144 MHz antenna will provide a more satisfactory load at
UHF as well, although with a compromised pattern on those
frequencies.

One of the most frightening tests I performed with 2m/440 ham
antennas was that they were extremely sharp in bandwidth and resulted
in extreme SWR beyond -+ 2-3 MHz on either band.

Public safety personnel often don't understand how hams can have high
performance dual band antennas and they can't. Some suspiciously
consider a conspiracy. The simple answer lies in the frequency
coordination of the repeater frequencies on both bands, and the
narrow but coincidental sliver of frequencies we use for mobile
operation.

If you have a telescopic whip you are blessed. Carry a tape measure
and chart with you.

Of course there are other issues regarding MURS, GMRS and FRS that
are completely awkward and you might as well carry a real FRS radio
along with a Commercial radio with a bank devoted to the ham bands on
your bat-belt.

I contest the mentality that says you should "open up" a ham radio
for "emergency use only" because you compromise the emergency
situation by not using a radio up to the task. You can use a
"church-key" as a can opener, but if you are truly serious you will
pack a can opener.

Jim, ac6tk


"Dave Platt" wrote in message
...
In article ,
Bruce W.1 wrote:

Does anyone make a telescoping HT antenna meant to operate (1/4
wave)
over a broad band of frequencies with marking for those
frequencies?

I've seen one or two such on a dealer's table at a local hamfest,
although I'm not sure that they come pre-marked - the package gave
instructions for the number of segments to collapse to achieve
resonance on 220 and 440. I think one was made by ADI and/or
Premier
but I can't be sure.

Most HT's can be modified to operate outside the amateur bands,
like on
GMRS, MURS, FRS, etc. But I don't like doing this without a
proper antenna.

You really shouldn't do it (well, at least, not transmit) even
_with_
a proper antenna. Very few, if any amateur-radio HTs are
certificated
for transmission on those bands, and using an "opened-up" ham HT to
transmit (even if you have a suitable GMRS license) is a rules
violation which could cost you your amateur ticket.

FRS and GMRS have very strict technical rules about the frequency
accuracy of their oscillators due to the tight inter-channel
spacings,
and it's likely that at least some ham HTs are too sloppy in design
(or too poorly calibrated) to hit the frequencies accurately.

--
Dave Platt
AE6EO
Hosting the Jade Warrior home page:
http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I
will
boycott any company which has the gall to send me such ads!