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CX2SA > SATDIG 30.05.09 19:55l 973 Lines 31925 Bytes #999 (0) @ WW
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From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
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Today's Topics:
1. Re: Satpc32 ooops (Erich Eichmann)
2. Re: eggbeater rx performance (Clint Bradford)
3. Re: FT-847 vs IC-910 (Alan P. Biddle)
4. Re eggbeater performance - mobile (mikehooles)
5. Re: help with satpc32 (Nick)
6. Eggbeater-AF6EP (Amateur Radio Station WA2S)
7. Fw: eggbeater rx performance (john heath)
8. Re: Re eggbeater performance - mobile (Bob Bruninga )
9. Re: Re eggbeater performance - mobile (jeff kb2m)
10. Re: Gulf Alpha antenna (Gary "Joe" Mayfield)
11. Re: eggbeater rx performance (Mobile Operation)
(Gary "Joe" Mayfield)
12. Re: eggbeater rx performance MM (MM)
13. Mobile Coax? (Bob Bruninga )
14. Re: eggbeater rx performance (Mobile Operation) (Bob Bruninga )
15. Re: Mobile Coax? (MM)
----------------------------------------------------------------------
Message: 1
Date: Sat, 30 May 2009 07:58:36 +0200
From: "Erich Eichmann" <erich.eichmann@xxxxxxxx.xx>
Subject: [amsat-bb] Re: Satpc32 ooops
To: <w7lrd@xxxxxxx.xxx>
Cc: amsat-bb@xxxxx.xxx
Message-ID: <61261FD8464F40E482B2C70F98C1609B@xxxxxxxxxxxxxx>
Content-Type: text/plain; format=flowed; charset="utf-8";
reply-type=original
Bob,
one possible reason could be a corrupted data file. There is a sub folder
"Data_Repair" in the SatPC32 DATA folder (the path of that folder is shown
in the bottom line of menu "Satellites"). Copy all files except Doppler.SQF
from the sub folder into the data folder "SatPC32" and restart the program.
If that doesn't help re-install the program.
73s, Erich, DK1TB
----- Original Message -----
From: <w7lrd@xxxxxxx.xxx>
To: <amsat-bb@xxxxx.xxx>
Sent: Saturday, May 30, 2009 4:00 AM
Subject: [amsat-bb] Satpc32 ooops
>
>
> Hello
>
> While using satpc32 with the lvbtracker I get a Ungulltige
> Gleitkammaoperation error message along with that bad "thunk" sound.
> What's going on??
>
> 73 Bob W7LRD
>
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>
------------------------------
Message: 2
Date: Fri, 29 May 2009 23:15:07 -0700
From: Clint Bradford <clintbrad4d@xxxxxxxxx.xxx>
Subject: [amsat-bb] Re: eggbeater rx performance
To: amsat-bb@xxxxx.xxx
Message-ID: <99C2BBB4-FA67-458F-AA74-B709468922D4@xxxxxxxxx.xxx>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
I set up my M2 EggBeater on a mast and rotator for shows and
conventions ... I call it my Souffle' Antenna.
(rim shot)
Clint Bradford, K6LCS
http://www.clintbradford.com
------------------------------
Message: 3
Date: Sat, 30 May 2009 02:28:34 -0500
From: "Alan P. Biddle" <APBIDDLE@xxxxxx.xxx>
Subject: [amsat-bb] Re: FT-847 vs IC-910
To: <amsat-bb@xxxxx.xxx>
Message-ID: <7B610320BA0244E28368C9C4D3FDE5CE@xxxxxx>
Content-Type: text/plain; charset="us-ascii"
I would also strongly recommend better filters than the stock ceramic
filters to do a comparison. When I bought FT-847 in 1998, Inrad did not
have compatible filters, so I bought the Collins mechanical filters which
were available. I did not do extensive testing, but the HF reception was
remarkably better than the stock filters.
Alan
WA4SCA
------------------------------
Message: 4
Date: Sat, 30 May 2009 08:10:10 -0000
From: "mikehooles" <mikehooles@xxxxxxxxxx.xxx>
Subject: [amsat-bb] Re eggbeater performance - mobile
To: <amsat-bb@xxxxx.xxx>
Message-ID: <C2A93F84EE684D06A057822154EE95A5@xxxx>
Content-Type: text/plain; charset="iso-8859-1"
For mobile work on AO27, SO50, AO51 a 2 metre quarter wave whip is all you
need with an IC-706 to work the LEO's when mobile and the satellite is 15
degrees or more above the horizon,
Regards
Mike G3LGR
------------------------------
Message: 5
Date: Sat, 30 May 2009 04:43:52 -0500
From: "Nick" <quadpugh@xxxxxxxxx.xxx>
Subject: [amsat-bb] Re: help with satpc32
To: "'Lowell White'" <whiteld@xxx.xxx>, <amsat-bb@xxxxx.xxx>
Cc: 'Matthew Triche' <shatteredmaul@xxxxx.xxx>
Message-ID: <010401c9e10b$24a5b820$6df12860$@xxx>
Content-Type: text/plain; charset="us-ascii"
This might be why I can not get satpc32 to work
nick
-----Original Message-----
From: Lowell White [mailto:whiteld@xxx.xxxx
Sent: Thursday, May 28, 2009 7:49 AM
To: Nick; amsat-bb@xxxxx.xxx
Subject: Re: [amsat-bb] help with satpc32
See if you can set explicit permission for satpce32 to be run as
administrator. I am presuming that the error is that the user doesn't have
adequate permission to run said program (or at least to make the change to
the
'rotator north' parm).
Right click on the program icon, select Properties, Shortcut tab, Advanced,
check the box to run as another user...
73,
Lowell
K9LDW
------ Original Message ------
Received: Thu, 28 May 2009 07:36:09 AM CDT
From: "Nick" <quadpugh@xxxxxxxxx.xxx>
To: <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] help with satpc32
> The UL is running xp and satpce32 the xp is set with administrator and a
> user profile and will not store the rotator North point parameter .
>
>
>
> Help ????
>
>
>
> Thanks
>
> nick
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>
------------------------------
Message: 6
Date: Sat, 30 May 2009 07:26:33 -0400
From: "Amateur Radio Station WA2S" <WA2S@xxxxxxx.xxx>
Subject: [amsat-bb] Eggbeater-AF6EP
To: <amsat-bb@xxxxx.xxx>
Message-ID: <B3D9739899184FE9B160002D2933A71D@xxxxxxxxxxxxxx>
Content-Type: text/plain; charset="us-ascii"
Hi Eric
If your goal is to work mobile while driving, your windows of opportunity
are going to be slim. I've done it, but effective air time will be pretty
short. On the portable side, I've been able to achieve VUCC Satellite using
5 Watts FT-60R handheld and an Arrow antenna mounted on a photo tripod
standing on the back deck. I also have the Elk but school's out on which I
prefer (for me- but most guys prefer the Elk). I've also built K5OE's
Eggbeater II for 2 meters which I have mounted in the attic along with an
antennas.us quadrifilar for 70 cm. Preamplifiers on both. Results are OK
but not as effective as even a simple directional antenna. I suspect that
the weak link is the quadrifilar and if I mounted a homebrew Eggbeater for
the downlink, it might improve results. Have also built EA4CYQ's "IOio"
handheld combo which works very well also. Go to http://www.eb4dka.tk to
see some great videos on how they work. Simple to build and effective for
portable work. Good luck.
73
Marc W4MPS
(formerly WA2S)
------------------------------
Message: 7
Date: Sat, 30 May 2009 12:44:37 +0100
From: "john heath" <g7hia@xxxxxxxxxx.xxx>
Subject: [amsat-bb] Fw: eggbeater rx performance
To: "amsat" <amsat-bb@xxxxx.xxx>
Message-ID: <955098C2A474461681507F4B902863D3@xxxxxx>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
----- Original Message -----
From: "john heath" <g7hia@xxxxxxxxxx.xxx>
To: <eric.fort@xxxxx.xxx>
Sent: Saturday, May 30, 2009 8:48 AM
Subject: Re: [amsat-bb] eggbeater rx performance
> Hi Eric,
>
> For the downlink on 70cm why not have a look at the paraistic Lindenblad
> design by Anthony Monteiro AA2TX. Its small and neat, excellent omni
> performance and has been "on air tested" with good results on all sats.
>
> Much easier to construct than a true Lindenblad, I have built both types.
>
> Good luck.
>
> 73 John G7HIA
>
------------------------------
Message: 8
Date: Sat, 30 May 2009 08:19:13 -0400 (EDT)
From: "Bob Bruninga " <bruninga@xxxx.xxx>
Subject: [amsat-bb] Re: Re eggbeater performance - mobile
To: mikehooles <mikehooles@xxxxxxxxxx.xxx>, amsat-bb@xxxxx.xxx
Message-ID: <20090530081913.AJV90004@xxx.xxxxxxx.xxxx.xxx>
Content-Type: text/plain; charset=us-ascii
> For mobile work on AO27, SO50, AO51
> a 2 metre quarter wave whip is all
> you need... to work the LEO's mobile
> and the satellite is 15 degrees or
> more above the horizon,
Absolutely, For a 19.5" whip in center of roof:
1) Has 5 dBi gain above 20 deg on 2m
2) Has 7+ dBi gain above 30 deg on 70cm
3) Is an omni
4) does not sacrifice 3 dB for circular
5) Above 25 deg, satellite is 6 to 10 dB closer!
6) works the birds solid for the center of high passes
7) Simplicity at its best!
Read about it: www.aprs.org/rotator1.html
Disadvantage: The only disadvantage is TIME. On the above web page you can
also see that satellites spend 70% of their daily pass times below 25 degrees.
BUT! For those best passes in the morning and the evening (or whenever) you
can make solid contacts while mobile for about 5 minutes.
Also note, that you do NOT need any tracking program to predict passes. AO51
schdule repeats evry 5 days for example. Just write down the CENTER pass of
the morning and evening for each day for 5 days. Update those 10 times on a
small 3/5" card on the dash about once a month or so will predict all passes
whenever you are mobile. There will be a pass 100 minutes earlier and 100
minutes later each day too. So you can predict all 6 passes a day from those
same 10 times.
See how: www.aprs.org/MobileLEOtracking.html
Bob, WB4APR
------------------------------
Message: 9
Date: Sat, 30 May 2009 08:35:34 -0400
From: "jeff kb2m" <kb2m@xxxxxxx.xxx>
Subject: [amsat-bb] Re: Re eggbeater performance - mobile
To: <amsat-bb@xxxxx.xxx>
Message-ID: <007401c9e123$210aca30$63205e90$@xxx>
Content-Type: text/plain; charset="us-ascii"
When I used to do a lot of driving for work I used to use a 1/4 wave, and a
high gain vertical antenna to work the birds. I would switch between the
high gain when the bird was coming up to the 1/4 wave when it was up 15
degrees or so. Then back to the high gain vertical when it was getting back
down below 15 degrees or so. Another good trick was to use the 1/4 for TX
only, and listen with 1/2 of an Arrow (with pre-amp) for the 70cm, D/L out
the drivers window, this would give you near armchair copy, when pulled over
of course !
73 Jeff kb2m
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of Bob Bruninga
Sent: Saturday, May 30, 2009 8:19 AM
To: mikehooles; amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Re: Re eggbeater performance - mobile
> For mobile work on AO27, SO50, AO51
> a 2 metre quarter wave whip is all
> you need... to work the LEO's mobile
> and the satellite is 15 degrees or
> more above the horizon,
Absolutely, For a 19.5" whip in center of roof:
1) Has 5 dBi gain above 20 deg on 2m
2) Has 7+ dBi gain above 30 deg on 70cm
3) Is an omni
4) does not sacrifice 3 dB for circular
5) Above 25 deg, satellite is 6 to 10 dB closer!
6) works the birds solid for the center of high passes
7) Simplicity at its best!
Read about it: www.aprs.org/rotator1.html
Disadvantage: The only disadvantage is TIME. On the above web page you can
also see that satellites spend 70% of their daily pass times below 25
degrees. BUT! For those best passes in the morning and the evening (or
whenever) you can make solid contacts while mobile for about 5 minutes.
Also note, that you do NOT need any tracking program to predict passes.
AO51 schdule repeats evry 5 days for example. Just write down the CENTER
pass of the morning and evening for each day for 5 days. Update those 10
times on a small 3/5" card on the dash about once a month or so will predict
all passes whenever you are mobile. There will be a pass 100 minutes
earlier and 100 minutes later each day too. So you can predict all 6 passes
a day from those same 10 times.
See how: www.aprs.org/MobileLEOtracking.html
Bob, WB4APR
------------------------------
Message: 10
Date: Sat, 30 May 2009 08:35:43 -0500
From: "Gary \"Joe\" Mayfield" <gary_mayfield@xxxxxxx.xxx>
Subject: [amsat-bb] Re: Gulf Alpha antenna
To: "'PE0SAT'" <pe0sat@xxxxx.xx>, "'Norman W Osborne'"
<ve3cje@xxxxx.xxx>
Cc: 'amsat-bb' <amsat-bb@xxxxx.xxx>
Message-ID: <COL0-DAV54FC9318B149E08059665E8A4E0@xxx.xxx>
Content-Type: text/plain; charset="us-ascii"
Gulf Alpha antennas are built better than any I have seen. They are very
robust!
A 5x5 is more than enough for any bird we currently have. With a good
pre-amp it would be good enough for hours of enjoyment on HEO.
73,
Joe
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of PE0SAT
Sent: Monday, May 25, 2009 6:26 AM
To: Norman W Osborne
Cc: amsat-bb
Subject: [amsat-bb] Re: Gulf Alpha antenna
On Mon, May 25, 2009 13:17, Norman W Osborne wrote:
Hi Norman,
I am looking for the samen information.
So can you keep me in the loop if there is some news.
They really look great :))
> Is there anyone using Gulf Alpha antenna's?
>
> I am looking for feedback as I am considering buying the 70cm X yagi.
One of the other questions I have, "2m Satellite 2x5 does it have enough
gain to work the birds?
> 73,
> Norman.
73's Jan - PE0SAT
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 11
Date: Sat, 30 May 2009 09:02:44 -0500
From: "Gary \"Joe\" Mayfield" <gary_mayfield@xxxxxxx.xxx>
Subject: [amsat-bb] Re: eggbeater rx performance (Mobile Operation)
To: "'Mark Lunday'" <mlunday@xx.xx.xxx>, <eric.fort@xxxxx.xxx>
Cc: 'Amsat BB' <amsat-bb@xxxxx.xxx>
Message-ID: <COL0-DAV44317E42D74134FD9935BC8A4E0@xxx.xxx>
Content-Type: text/plain; charset="us-ascii"
I have operated while driving. I found a trunk mounted 2 meter half wave
(dual bander) to work well when the satellite was behind me, but not at all
overhead or in front of the car (makes sense). I currently have a 2 meter
quarter wave (dual bander) mounted by drilling into the center of the roof.
It works in all directions (again makes sense).
I have always operated full duplex, usually with a headset mic, but
sometimes without. The following radios have worked for me.
Yaesu FT-4700 -- The first radio I did it with.
Icom IC-2340 -- Worked okay
Icom IC-2720 -- Worked great (One side hears better than the other) the
radio has "other" issues
Yaesu FT-8900 -- Works very well
Mode B is vastly superior to mode J for mobile operation. AO-21 and SO-35
rocked beyond belief!
73,
Joe kk0sd
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of Mark Lunday
Sent: Friday, May 29, 2009 11:11 PM
To: eric.fort@xxxxx.xxx
Cc: 'Amsat BB'
Subject: [amsat-bb] Re: eggbeater rx performance
Good question. With Arrow/Elk, it is directional. Good gain but not omni.
With whip it is omni, but reduced gain.
Don't know of anyone who operated while driving, so I cannot help you with
that one. Maybe eggbeater is the way to go.
Mark Lunday
WD4ELG
<mailto:wd4elg@xxxx.xxx> wd4elg@xxxx.xxx
<http://wd4elg.net> http://wd4elg.net
From: Eric Fort [mailto:eric.fort@xxxxx.xxxx
Sent: Friday, May 29, 2009 11:18 PM
To: Mark Lunday
Cc: Amsat BB
Subject: Re: [amsat-bb] eggbeater rx performance
I have an arrow. It's just sorta difficult to point when in motion. Is the
pattern from a standard mobile whip really enough considering polorization
and radiation angle or would something else be more effective? I'm looking
to move from working portable to truly mobile.
Eric
AF6EP
On Fri, May 29, 2009 at 7:46 PM, Mark Lunday <mlunday@xx.xx.xxx> wrote:
Eric
Couple of thoughts for you:
No need for QRO, in my opinion. You can solve it all with a good antenna
setup.
Regarding antennas...nothing against eggbeaters, but you can accomplish
everything with a simple antenna setup, including mobile: Look for Elk
antennas and Arrow antennas, hand held and directional. Lots of great
success w/o anything other than 5 watts and one of those antennas. Ask
WD9EWK and N3TL, who have proven this over and over.
Mark Lunday
WD4ELG
wd4elg@xxxx.xxx
http://wd4elg.net
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 12
Date: Sat, 30 May 2009 07:04:12 -0700 (PDT)
From: MM <ka1rrw@xxxxx.xxx>
Subject: [amsat-bb] Re: eggbeater rx performance MM
To: Amsat BB <amsat-bb@xxxxx.xxx>, eric.fort@xxxxx.xxx
Message-ID: <544827.78808.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=utf-8
Let?s split your question into two parts
Car and House:
I have made literally hundreds of FM voice contacts with Mir and ISS from my
car. I have also made hundreds of packet mail contacts with Mir.
On Mir the default power setting was 5 watts, into a Larsen Dual band Mobile
antenna, mounted outside on the hull of Mir. The transceiver was either a
Kenwood TM-733 or TM-V7A.
My car station was typically a 5/8 wave mono band 2-meter vertical, with a 45
watt class FM rig. I usually did not have the amps in the car since mobile
amps are typically high maintenance.
ISS is running a similar setup. The transceiver is a Kenwood TM-D700,
modified for three power settings, 5,10,25 (special mods). The ISS D700 has
been programmed to default to 10 watts for voice and packet, unless changed by
the crew, however every time the crew pushes a PM/function button, it forces
the radio back to 10 watts.
The antenna is a Quad band system with 2, 440, patch for 1.2-2.4 Ghz. Gain is
unknown, and must be assumed to be ?3dBd for 2 meters.
So for beginners, LEO satellites, Running simple verticals and a 45+ watt
class system and 0 dBd gain antennas is a good way to start from your car
(parked or driving).
You will need to Pick your orbits in advance. I would usually only attempt
orbits that were 45 degrees elevation or better from my Car.
For the more advances mobile users, try this Mobile EME array.
http://www.garysicecream.com/may909.htm
Other Car Tips:
Convert from RG-58 to LMR-240-UF or RG-213. The coax that usually comes with
stock mobile antennas is too poor of quality to be used seriously.
Run Mono-band antennas for 2 and 440, get the highest Gain mono band (whip)
antennas that will fit your mobile and garage. You may need a signal splitter
since most rigs only have one SO-239 for 2/440.
Amps for your Car:
Get best antennas and coax first before using amps. In some States, we are
limited to 50 watts on 440.
House Satellite Antennas:
It?s ok to start with a few simpler verticals or small beams to see if you
like the satellite hobby.
If you do like Satellites and want to continue then you have two choices.
#1 Gradually build your antenna gain over several years,
1 Element 0 dBd
2 Elements 3dBd
4 Elements 6dBd
8 Elements 9 dBd
etc.
or
#2 you can jump in and buy a one of the 20+ element CP (circular polarized)
12-dBd class beams.
In many cases it maybe cheaper to go from 0 dBd to 12 dBd than buying lots of
little antennas in-between. A CP style antenna system can be used for both
Satellite and terrestrial DX.
Other Tips:
Go with the most elements you can afford for a single boom.
20+ elements on 2-meters
40+ elements on 440
Coax:
You can now get Flexible thick coax that will support an antenna Rotor.
Most people used RG-8 style coax, which is approximately 10 mm in diameter.
However you can now get flexible rotor grade coax which is approximately 15 mm
in diameter, and has much lower loss than the best RG-8 style coax.
Example:
Belden RG-213
145 MHz 2.5 dB loss per 100 feet
438 MHz 4.5 dB loss per 100 feet
LMR 600 UltraFlex Rotor cable
145 MHz 1.1 dB loss per 100 feet
438 MHz 2.0 dB loss per 100 feet
As you can see, by switching from 10mm coax to 15mm coax you can reduce you
loss by over 50%. The 15mm cables cost 2-3 times as much, however you will not
have to worry about coax losses any more on Frequencies below 2 gig.
73 wf1f
--- On Fri, 5/29/09, Eric Fort <eric.fort@xxxxx.xxx> wrote:
> From: Eric Fort <eric.fort@xxxxx.xxx>
> Subject: [amsat-bb] eggbeater rx performance
> To: "Amsat BB" <amsat-bb@xxxxx.xxx>
> Date: Friday, May 29, 2009, 9:17 PM
> I/m interested in the possibility of
> using oscars 27, 29, 50, 51, and 52
> without using rotors or directional antennas and maybe
> while mobile.? Uplink
> seems not to be a problem as one can always QRO to a level
> where the
> satellite sees an apropriate signal level that is enough
> but without robing
> power from other transponder users.? On recieve though
> you still gotta be
> able to hear 'em to work 'em.? Is an eggbeater and a
> preamp enough to hear
> decently or is there another (better) way?? Is working
> mobile and/or without
> directional antennas even practical?? what's the best
> way to do it?
>
> Thanks,
>
> Eric
> AF6EP
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx.
> Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur
> satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>
------------------------------
Message: 13
Date: Sat, 30 May 2009 10:48:59 -0400 (EDT)
From: "Bob Bruninga " <bruninga@xxxx.xxx>
Subject: [amsat-bb] Mobile Coax?
To: Amsat BB <amsat-bb@xxxxx.xxx>
Message-ID: <20090530104859.AJV90615@xxx.xxxxxxx.xxxx.xxx>
Content-Type: text/plain; charset=us-ascii
> Other Car Tips:
> Convert from RG-58 to LMR-240-UF
> or RG-213.
I'd take that with a grain of salt. The length of coax in a car is about say
10 feet. The loss of 100 feet of RG-58 is say 5 dB? and the loss of fancy
stuff might be 3 db? But the diffrence for only a 10 foot run is only .5 dB
versus .3 dB or only 0.2 dB. Nothing at all to even consider compared to all
the work it will take, and the lack of flexibility and trying to run something
almost like pipe through places where a simple wire (RG-58) fits.
My lesson was learned 40 years ago when I go my first 100 lb UHF mobile rig
(tubes) just after highschool. The boat anchor filled the entire trunk of my
MGB. But the first thing I did when we go the lot of them in my club was
spend a day replacing the 8" internal piece of RG-58 in mine from the
Transmitter output over to the chassis connector with a 8" run of RG-8. It
was hard work getting that 8" piece of RG-8 coax inside the radio and routed
all around the internal chassis.
The elmer at the time laughed. He said you just wasted a day and all that
work to save 0.01% of loss. So now your radio works at 100% where as before
it worked at 99.99%. Losing 3 dB of course is one thing (50%), but trying to
worry about that last 1% when the effort is tremendous is just not effective.
Anyway, just my 2 cents...
Bob, Wb4APR
------------------------------
Message: 14
Date: Sat, 30 May 2009 11:01:08 -0400 (EDT)
From: "Bob Bruninga " <bruninga@xxxx.xxx>
Subject: [amsat-bb] Re: eggbeater rx performance (Mobile Operation)
To: Gary "Joe" Mayfield <gary_mayfield@xxxxxxx.xxx>, "'Mark Lunday'"
<mlunday@xx.xx.xxx>, eric.fort@xxxxx.xxx
Cc: 'Amsat BB' <amsat-bb@xxxxx.xxx>
Message-ID: <20090530110108.AJV90668@xxx.xxxxxxx.xxxx.xxx>
Content-Type: text/plain; charset=us-ascii
> I found a trunk mounted 2 meter half wave
>(dual bander) to work well when the satellite
> was behind me, but not at all overhead...
> I currently have a 2 meter quarter wave
> (dual bander) mounted... into the center
> of the roof. It works in all directions...
Any "gain" antenna on a car is not good for satellites. Because by
definition, "gain" in a mobile means "gain" on the horizon where mobiles need
it, and this means LOSS everywhere else. The better the antenna is for
"mobile" the worse it is for satelliites. (basic law of physics)..
Eevn the "dual bander" 2 meter 1/4 wave has a decopuling loop for UHF, to keep
the angle of UHF radition low on the horizon, because without it, the 1/4 2m
whip is a 3/4 UHF whip and results in gain ABOVE 25 degrees which is BAD for
terrestrial work (but GOOD by 2 dB or mnore for satellites).
So, when we say a 19.5" 1/4 wave 2m whip for mobile satellite, then that is
all it is. No matching, no coils for UHF, no nothing. Just a 19.5" vertical
whip. BUT for satellites, this 19.5" whip is also a 3/4 wave UHF whip which
has almost 7 dBi of gain ABOVE 25 degrees which is where it really yields
solid performance for LEO satellites when above 25 degrees.
A 5/8 wave 2m whip has a NULL at 15 degrees and so it is useless for
satellites. They are too far away below 10 degrees to hear, and then there is
the null up to say 45 degrees. And above that the satellite is only in view
for 2 minutes or less! AND this antenna cannot be used on UHF at all.
So that is why the 19.5" vertical in the middle of the roof is the best for
mobile satllite (and not all that hot for terrestrial... but useable, since
repeaters are a lot closer).
See details about 75% down this page:
www.aprs.org/astars.html
Good luck.
Bob, Wb4APR
------------------------------
Message: 15
Date: Sat, 30 May 2009 09:00:15 -0700 (PDT)
From: MM <ka1rrw@xxxxx.xxx>
Subject: [amsat-bb] Re: Mobile Coax?
To: Amsat BB <amsat-bb@xxxxx.xxx>, Bob Bruninga <bruninga@xxxx.xxx>
Message-ID: <621129.55565.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=utf-8
Hi Bob,
You comments are valid for 2-meters. You are not going to see much difference
between 15 feet of cheap coax and good coax. Howver, as you go higher in
frequency the losses increase.
On the 440 band the Coax Loss difference between 15 feet of RG-58 and LMR-240
is approximately 1 dB.
For Raw power, switching from 15 feet of RG-58 (~5 millimeter cable) and LMR-
240 (-6 Millimeter cable) will give you 15-20% more RF at the antenna.
So for people that are counting dB?s in mobile setup, this is just one more
option to squeeze out a little more performance.
And for those of you what want to run amplifiers on 440, you will find that
RG-58 has approximately a 105-watt limit. The LMR-240 (-6 Millimeter cable)
will support 380 watts.
Here in Boston, Hams are starting to used 900 Mhz repeaters. The stock RG-58
coax just sucks up your TX and RX power on 900 mhz.
Low Loss Coax for Home and Mobile usage
Hi all:
Most of the mobile antennas mounting systems that come with coax use the
cheapest and highest loss coax available. If you read the fine print
on these coaxes you will be surprised to find that your power loss may
be as high as 40% and the coax will melt above 110 watts (on 440 mc).
More and more of us are using 440 and higher frequencies. By selecting
the correct coax you can save 1 or more DB of loss, even for a short
length as 15 feet.
Here are some number I put together on coax loss for the typical mobile
installation.
dB Loss (440 mc) dB Loss (900 mc)
Length FT TX Freq/Length
15' 100' Pwr 15' 100' Pwr
Size Center
RG-58/U 1.5 9.9 105w 2.2 14.5 60w
.195"
.032
RG-58/A 1.5 9.9 105w 2.2 14.5 60w
.195"
Stranded
RG-8X 1.2 8.1 250w 1.8 12.1 150w
.240"
Stranded
LMR-240UF 0.5 3.2 380w 0.7 4.7 260w .240"
.059
The coax RG-58 comes in many flavors, No letter, A, C and U.
The letter "U" is sometimes a solid 20 AWG copper center.
The letters "A" and "C" are stranded, the center size would be similar
to solid, and will have a little more loss than Solid center.
Most mobile installations will need 15 to 17 feet of coax.
RG-8X and LMR-240 are the same size, however LMR has foil shield and
lower published loss values. The UF version of 240 is the Ultra Flex
flavor and can bend easier with a only a slight change in loss ratings.
>From this list of small car style coax, the LMR beats them all; in
lowest loss for the size and highest transmit power loads. I was
planning on installing a 440 AMP in my car, but after looking at the
coax, I realized that I would fry the stock RG-58 coax.
I was looking for an NMO Mag mount that has LMR-240 installed. I was
not able to find any, so I made my own. I took a Round style Larsen NMO
mount and replaced the existing RG-58A coax with LMR-240. Use two screw
drivers to pop the magnet off the metal mount. Remove the two Phillips
screws hidden under the magnet. Remove the metal frame and now you will
have access to the coax mounting point. Replace coax and glue on the
magnet with epoxy cement.
145 meg
45 watts, in, 15 feet of LMR-240, = 40 watts out
45 watts, in, 15 feet of RG-58, = 37 watts out (~10% power loss difference)
440 meg
20 watts, in, 15 feet of LMR-240, = 17 watts out
20 watts, in, 15 feet of RG-58, = 14 watts out (15-20% power loss difference)
900 meg
10 watts, in, 15 feet of LMR-240, = 7.7 watts out
10 watts, in, 15 feet of RG-58, = 5.8 watts out
Power reference
http://www.ocarc.ca/coax.htm
73 Miles
--- On Sat, 5/30/09, Bob Bruninga <bruninga@xxxx.xxx> wrote:
> From: Bob Bruninga <bruninga@xxxx.xxx>
> Subject: [amsat-bb] Mobile Coax?
> To: "Amsat BB" <amsat-bb@xxxxx.xxx>
> Date: Saturday, May 30, 2009, 10:48 AM
> > Other Car Tips:
> > Convert from RG-58 to LMR-240-UF
> > or RG-213.?
>
> I'd take that with a grain of salt.? The length of
> coax in a car is about say 10 feet.? The loss of 100
> feet of RG-58 is say 5 dB? and the loss of fancy stuff might
> be 3 db?? But the diffrence for only a 10 foot run is
> only .5 dB versus .3 dB or only 0.2 dB.? Nothing at all
> to even consider compared to all the work it will take, and
> the lack of flexibility and trying to run something almost
> like pipe through places where a simple wire (RG-58) fits.
>
> My lesson was learned 40 years ago when I go my first 100
> lb UHF mobile rig (tubes) just after highschool.? The
> boat anchor filled the entire trunk of my MGB.? But the
> first thing I did when we go the lot of them in my club was
> spend a day replacing the 8" internal piece of RG-58 in mine
> from the Transmitter output over to the chassis connector
> with a 8" run of RG-8.? It was hard work getting that
> 8" piece of RG-8 coax inside the radio and routed all around
> the internal chassis.
>
> The elmer at the time laughed.? He said you just
> wasted a day and all that work to save 0.01% of loss.?
> So now your radio works at 100% where as before it worked at
> 99.99%.? Losing 3 dB of course is one thing (50%), but
> trying to worry about that last 1% when the effort is
> tremendous is just not effective.
>
> Anyway, just my 2 cents...
>
> Bob, Wb4APR
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx.
> Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur
> satellite program!
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>
------------------------------
_______________________________________________
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End of AMSAT-BB Digest, Vol 4, Issue 247
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