[rebel-builders] icom vhf radio / HF radios
Posted: Sun Feb 19, 2012 4:01 pm
Hi Eddie
Best bet is something like an ICOM 706 that has been modified to transmit
over the whole HF portion, Fairly common in ham radio circles at I guess
about 800 CAN . It will need about 25 amps at full power.
You'll need some kind of small aerial tuning unit as well to tune the wire
you'll be running from the cabin to an insulator at the tip of the fin and
from there to the wingtip (not that I'm doing that of course :-)
Nig
745E
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com]On Behalf Of
Eddie Moran
Sent: 12 October 2007 03:45
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] icomm vhf radio
Huh?
Wow, I understood about 10% of that. Let me ask this. Is there anyway
that one
can put together a "HF" radio at a reasonable price?
Eddie Moran
Garry Wright <wrightdg@davincibb.net> wrote:
Walter,
The effect of the power is pretty limited where mountains are concerned.
VHF is strictly line of sight with a bit of diffraction around knife
edges in the rocks.
If you can hear them though, it should be possible to put out enough
power that they can hear you. The highest power radio is easy. A better
antenna and antenna placement is also possible.
Most of the antennas on aircraft are 1/4 wavelength monopoles. The
antenna improvemnent potential is about the same as going from 5 watts
to 8 watts. A 5/8 wavelenght antenna similar to vhf mobile antennas
could be made up and if mounted on the roof of the aircraft for best
overall coverage, that would be as good as it gets. The 5/8 wavelength
antenna has a loading coil at the bottom (which would probably be
sub-optimal) if one got an old mobile vhf antenna for about 140 Mhz from
a surplus operator. You could follow Ken's suggestion and using a vswr
meter try to optimize the tuning of the antenna. Length should be close
to 5/8 wavelength, tune the shape and spacing of the loading coil for
low reflected power. Do not touch the antenna while transmitting. RF
burns are not particularly pleasant but 8 watts isn't very hot.
Most people won't use a 5/8 antenna because it is long and tends to lean
back in the wind. A piece of fish line can keep it straight if one
wishes. It is also a bit more drag.
If you want to stay with the 1/4 wavelenght antenna, all you can do is
be sure it has a low reflected power and is put in a good position to
'see' the target antenna.
Garry
Walter Klatt wrote:
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Best bet is something like an ICOM 706 that has been modified to transmit
over the whole HF portion, Fairly common in ham radio circles at I guess
about 800 CAN . It will need about 25 amps at full power.
You'll need some kind of small aerial tuning unit as well to tune the wire
you'll be running from the cabin to an insulator at the tip of the fin and
from there to the wingtip (not that I'm doing that of course :-)
Nig
745E
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com]On Behalf Of
Eddie Moran
Sent: 12 October 2007 03:45
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] icomm vhf radio
Huh?
Wow, I understood about 10% of that. Let me ask this. Is there anyway
that one
can put together a "HF" radio at a reasonable price?
Eddie Moran
Garry Wright <wrightdg@davincibb.net> wrote:
Walter,
The effect of the power is pretty limited where mountains are concerned.
VHF is strictly line of sight with a bit of diffraction around knife
edges in the rocks.
If you can hear them though, it should be possible to put out enough
power that they can hear you. The highest power radio is easy. A better
antenna and antenna placement is also possible.
Most of the antennas on aircraft are 1/4 wavelength monopoles. The
antenna improvemnent potential is about the same as going from 5 watts
to 8 watts. A 5/8 wavelenght antenna similar to vhf mobile antennas
could be made up and if mounted on the roof of the aircraft for best
overall coverage, that would be as good as it gets. The 5/8 wavelength
antenna has a loading coil at the bottom (which would probably be
sub-optimal) if one got an old mobile vhf antenna for about 140 Mhz from
a surplus operator. You could follow Ken's suggestion and using a vswr
meter try to optimize the tuning of the antenna. Length should be close
to 5/8 wavelength, tune the shape and spacing of the loading coil for
low reflected power. Do not touch the antenna while transmitting. RF
burns are not particularly pleasant but 8 watts isn't very hot.
Most people won't use a 5/8 antenna because it is long and tends to lean
back in the wind. A piece of fish line can keep it straight if one
wishes. It is also a bit more drag.
If you want to stay with the 1/4 wavelenght antenna, all you can do is
be sure it has a low reflected power and is put in a good position to
'see' the target antenna.
Garry
Walter Klatt wrote:
5You're right Ken. I looked at it again, and it listed the Europe output as
radiosbut the USA was 8. So that is not too bad. I don't know enough about
relatedeither, to know how much difference that makes. All I know is that I want
more transmit range.
Looks like a nice radio, but would like to see it out for a while too, to
see the price come down. Maybe I can live with my current one a little
longer. It is just that I will have my panel off to do other things
veryto the new engine, so this would be a good time.
I like the idea of monitoring two frequencies at the same time. That is
differentrelevant where I fly here, because of our congested VFR space and
wattfrequencies in close proximity.
Walter
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Ken
Sent: Thursday, October 11, 2007 5:18 PM
To: rebel-builders@dcsol.com
Subject: [rebel-builders] icomm vhf radio
Walter the brochure that I looked at listed 8 watts of carrier which is
respectable. As I understand it the difference in range between 8 watts
and half that is hardly noticeable but getting the SWR of the antenna
correct is a big factor. The aeroelectric list sometimes asks if you
know any HAM radio operators that might have an SWR meter but I don't
know much about antennas. I would predict that icom will offer $200.
rebates at sun'n fun in addition to competitive pricing. I am not
impressed by the A200 LCD display so I like the A210 display. My A200
is quite sensitive to mic gain adjustments but for all I know all radios
are.
Ken
Walter Klatt wrote:
I checked into this and ended up talking to Tom Glaze at ACS. They needed
500 orders to get that 1058 price, but unfortunately they have only about
100 right now, and likely won't make it to 200 by tomorrow.
While this radio has some nice features, I noticed that it only has 5
withtransmit output. I thought most had 7 and some have 10.
Some of the places I fly in the mountains here, I am often out of rangetransmit. I can hear a long ways, but can't talk to them.
Walter
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