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CX2SA > SATDIG 14.05.13 07:22l 767 Lines 27815 Bytes #999 (0) @ WW
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Today's Topics:
1. Elk antenna review in QST (Alan)
2. Isle of Mull Grid IO76 on Satellites (M5AKA)
3. Re: ISS HamTV Frequencies (M5AKA)
4. Re: J-Pole Antenna (Gregg Wonderly)
5. Helical Antenna on 70 cm (Rolf Krogstad)
6. Re: Satellite Demonstration Passes for Dayton 2013 (Rolf Krogstad)
7. Re: Helical Antenna on 70 cm (Bob- W7LRD)
8. Re: Helical Antenna on 70 cm (Rolf Krogstad)
9. Re: Helical Antenna on 70 cm (Greg D)
10. Re: Helical Antenna on 70 cm (Greg D)
11. Re: Helical Antenna on 70 cm (Jim Jerzycke)
12. Re: ISS HamTV Frequencies (Greg D)
13. Re: ISS HamTV Frequencies (Daniel Schultz)
14. Re: Helical Antenna on 70 cm (i8cvs)
----------------------------------------------------------------------
Message: 1
Date: Mon, 13 May 2013 14:07:42 -0500
From: Alan <wa4sca@xxxxx.xxx>
To: "AMSAT-BB" <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Elk antenna review in QST
Message-ID: <D8D10DB3494A429FAEC031FFEA6CA803@xxxxxx>
Content-Type: text/plain; charset="us-ascii"
Hi,
There is an interesting, positive short review of the Elk 2M/440L5 in the
June issue of QST, page 56.
He covers both satellite and terrestrial VHF contest use. If you are a
League member and don't have
the paper issue, the article by Steve Ford, WB8IMY is available for download
or on line reading at
www.arrl.org/qst.
These antennas, as well as a case, will be available at the AMSAT booth at
Dayton, and are easily
transported home when disassembled.
73s,
Alan
WA4SCA
------------------------------
Message: 2
Date: Mon, 13 May 2013 21:15:20 +0100 (BST)
From: M5AKA <m5aka@xxxxx.xx.xx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Isle of Mull Grid IO76 on Satellites
Message-ID:
<1368476120.34214.YahooMailClassic@xxxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=utf-8
The Camb-Hams group GS3PYE/P are active until May 16 from the Isle of Mull,
Grid IO76, in Scotland. Listen out for them on VO-52 and FO-29.
GS3PYE/P
http://www.southgatearc.org/news/may2013/gs3pye.htm
73 Trevor M5AKA
------------------------------
Message: 3
Date: Mon, 13 May 2013 21:33:13 +0100 (BST)
From: M5AKA <m5aka@xxxxx.xx.xx>
To: Daniel Schultz <n8fgv@xxx.xxx>, amsat-bb@xxxxx.xxxxxxxxx Dolkas
<ko6th.greg@xxxxx.xxx>
Subject: [amsat-bb] Re: ISS HamTV Frequencies
Message-ID:
<1368477193.60216.YahooMailClassic@xxxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=iso-8859-1
--- On Mon, 13/5/13, Greg Dolkas <ko6th.greg@xxxxx.xxx> wrote:
> Is there something about the DVB-S modulation that makes it
> astoundingly better for this application?? For
> something that is intended to be widely received, they sure
> are making it difficult...
DVB-S receivers are in use in hundreds of millions of homes around the
world. Apart from DVB-S2, which is not yet so widespread, I'm not aware of
any other standard that would deliver better performance in a 2 MHz bandwidth.
73 Trevor M5AKA
------------------------------
Message: 4
Date: Mon, 13 May 2013 16:43:11 -0500
From: Gregg Wonderly <w5ggw@xxx.xxx>
To: Robert Bruninga <bruninga@xxxx.xxx>
Cc: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Re: J-Pole Antenna
Message-ID: <51915E6F.50209@xxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Bob, depending on the antenna pattern and the ground, as you say, 15 degrees
might be too low for any additional help toward the horizon. 30 to 35 degrees
will give you a little better results for stuff that isn't just right at the
horizon, I feel. As with all things in this hobby, experimentation with your
equipment will allow you to find the best combination.
Gregg Wonderly
W5GGW
On 5/13/2013 11:29 AM, Robert Bruninga wrote:
>> As has been said many times, most satellite passes are never
>> "directly overhead", but rather on some inclination across the sky.
>> A 5 element yagi antenna, at a 35 degree angle from the horizon,
>> with only an asmuth rotator, will let you work far more satellites for
> the money spent.
>
> Except that the correct angle is 15 degrees not 30 or 35. At 15
> degrees, the main gain lobe of the antenna still has excellent gain on the
> horizon where you need it most and an equal gain all the way up to 30
> degrees or so. Below 30 degrees is where satellites spend 80+% of their
> in-view times. This is where you need the gain most. But when the
> satellite is above 30 degrees, the satellite is at least 6 to 10 dB closer
> and so it makes no sense to sacrifice gain on the horizon (where you need
> it most) by placing it at 30 degrees where you need it least.
>
> See http://aprs.org/rotator1.html
>
> Ignore the topic of the page but look very carefullyl at the SCALE drawing
> (Yes, that is drawn to scale) of a LEO satellite pass Notice how 95% of
> all satellite access times are below 50 degrees and 70% of the time they
> are below 22 degrees. That is where you need the gain. Do not waste it
> by tilting the antenna up more than 15 degrees.
>
> The only exception is that if your beam antenna cannot see the horizon
> anyway, then, yes, tilt it up a little more since you wont hear the low
> stuff anyway...
>
> Bob, WB4aPR
>
>
>
> Gregg Wonderly
>
> On 5/12/2013 12:48 PM, Jeff Moore wrote:
>> I wouldn't recommend a J-pole for satellite work unless you expect to
>> only work sats on the horizon. The J-Pole antenna has a low take-off
>> angle and almost NO radiation overhead, an plain 1/4 wave ground
>> plane antenna would work better for the sats.
>>
>>
>>
>> J-poles are great terrestrial communications antennas, not so much for
>> working overhead satellite passes. An Eggbeater or quadrifiliar
>> antenna would be a better choice.
>>
>> 7 3
>>
>> Jeff Moore -- KE7ACY
>>
>> On 5/12/2013 8:00 AM, Werner, HB9BNK wrote
>>> Thank you all for your valuable hints and advices !
>>>
>>> I will now build such an antenna and then supply here the results.
>>>
>>> 73 Werner, HB9BNK
>>
>> _______________________________________________
>> 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
>>
> _______________________________________________
> 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
> _______________________________________________
> 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: 5
Date: Mon, 13 May 2013 11:22:57 -0500
From: Rolf Krogstad <rolf.krogstad@xxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Helical Antenna on 70 cm
Message-ID:
<CAJJyj=bi=Nm-PBNzEicE=DE+62hN2QW+_AFh+SykYD9L-JiSzw@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
I am new to satellites and new to the design requirements for UHF and am
looking for advice.
I am looking to build a Helical antenna for the 70cm Band. I am
considering the plans for such an antenna from the 2010 edition of the ARRL
Satellite Handbook. The plans call for a 235 cm (7' 8") long, 2.5 cm (1")
diameter center support made of either a wooden dowel which has been
treated or a fiberglass tube. It also requires multiple 7.6 cm (3")
spacers for the helical element.
My question is would fiberglass rods made of "Isophthlic Polyester Resin"
be a good choice of material at UHF frequencies?
I hesitate to use treated wood because I plan to mount this on the top of a
15 meter high tower and it isn't very accessible.
Thanks
Rolf NR0T
[EN34]
------------------------------
Message: 6
Date: Mon, 13 May 2013 12:02:54 -0500
From: Rolf Krogstad <rolf.krogstad@xxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Re: Satellite Demonstration Passes for Dayton 2013
Message-ID:
<CAJJyj=YFEe6_vO6myLa8wMPY8tF8V9Lm_kCasMk3FrrOAa4xxQ@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
What callsign will be used - W5IU?
de Rolf NR0T
>>> ---------- Forwarded message ----------
>>> From: "Keith Pugh" <w5iu@xxxxxx.xxx>
>>> To: <amsat-bb@xxxxx.xxx>
>>> Cc:
>>> Date: Mon, 13 May 2013 00:03:08 -0500
>>> Subject: [amsat-bb] Satellite Demonstration Passes for Dayton 2013
>>> Here are the Satellite Demonstration Passes for Dayton 2013, 17-19 May.
>>> Times are in UTC. We will work as many of these passes as possible -
>>> weather and equipment permitting. The days are Friday, 17 May, through
>>> Sunday, 19 May. The original plain text file is attached with the
original
>>> formatting. See you on the "Birds" at Dayton 2013 this weekend.
>>>
>>> 73 - Keith, W5IU
------------------------------
Message: 7
Date: Tue, 14 May 2013 01:21:08 +0000 (UTC)
From: Bob- W7LRD <w7lrd@xxxxxxx.xxx>
To: Rolf Krogstad <rolf.krogstad@xxxxx.xxx>
Cc: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Re: Helical Antenna on 70 cm
Message-ID:
<720778933.871995.1368494468761.JavaMail.root@xxxxxxx.xxxxxxxxxx.xx.xxxx.xxxxx
xx.xxx>
Content-Type: text/plain; charset=utf-8
the helix is a nice antenna...however...once wound for either RHCP or LHCP
there's no going back. So switching from R to L or L to R is out of the
question. Unless of course the chosen polarity is always compatible with the
satellite in use. Unless you have L and a R helix and switch between them,
that can get a "little" involved. Many times it is very convenient to be
able to switch between L or R during a pass, at times it can make the
contact happen. This is of course is easy with a L/R CP yagi. I have used a
helix for L band (1.2ghz ) as well as feeds for a 2.4ghz dish. They are a
fine antenna with a fair amount of bandwidth. For a 16+ turn helix I have
used stainless steel "U" channel for the center support. If Clair, VE3NPC is
listening, he's the resident helix guy. Just my opinion, your mileage may
differ.
73 Bob W7LRD
Seattle
----- Original Message -----
From: "Rolf Krogstad" <rolf.krogstad@xxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Sent: Monday, May 13, 2013 9:22:57 AM
Subject: [amsat-bb] Helical Antenna on 70 cm
I am new to satellites and new to the design requirements for UHF and am
looking for advice.
I am looking to build a Helical antenna for the 70cm Band. I am
considering the plans for such an antenna from the 2010 edition of the ARRL
Satellite Handbook. The plans call for a 235 cm (7' 8") long, 2.5 cm (1")
diameter center support made of either a wooden dowel which has been
treated or a fiberglass tube. It also requires multiple 7.6 cm (3")
spacers for the helical element.
My question is would fiberglass rods made of "Isophthlic Polyester Resin"
be a good choice of material at UHF frequencies?
I hesitate to use treated wood because I plan to mount this on the top of a
15 meter high tower and it isn't very accessible.
Thanks
Rolf NR0T
[EN34]
_______________________________________________
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: 8
Date: Mon, 13 May 2013 21:04:12 -0500
From: Rolf Krogstad <rolf.krogstad@xxxxx.xxx>
To: Bob- W7LRD <w7lrd@xxxxxxx.xxx>
Cc: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Re: Helical Antenna on 70 cm
Message-ID:
<CAJJyj=bn3-ub77cG_Hj2Ok6f7uWJMadX6XwEa+z25_sTv2_aZQ@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
Thanks, Bob.
Is there a commercial yagi available for 435 MHz which is R-L switchable?
Rolf NR0T
On Mon, May 13, 2013 at 8:21 PM, Bob- W7LRD <w7lrd@xxxxxxx.xxx> wrote:
> the helix is a nice antenna...however...once wound for either RHCP or LHCP
> there's no going back. So switching from R to L or L to R is out of the
> question. Unless of course the chosen polarity is always compatible with
> the satellite in use. Unless you have L and a R helix and switch between
> them, that can get a "little" involved. Many times it is
> very convenient to be able to switch between L or R during a pass, at times
> it can make the contact happen. This is of course is easy with a L/R CP
> yagi. I have used a helix for L band (1.2ghz ) as well as feeds for a
> 2.4ghz dish. They are a fine antenna with a fair amount of bandwidth. For
> a 16+ turn helix I have used stainless steel "U" channel for the center
> support. If Clair, VE3NPC is listening, he's the resident helix guy.
> Just my opinion, your mileage may differ.
> 73 Bob W7LRD
> Seattle
>
> ------------------------------
> *From: *"Rolf Krogstad" <rolf.krogstad@xxxxx.xxx>
> *To: *amsat-bb@xxxxx.xxx
> *Sent: *Monday, May 13, 2013 9:22:57 AM
> *Subject: *[amsat-bb] Helical Antenna on 70 cm
>
>
> I am new to satellites and new to the design requirements for UHF and am
> looking for advice.
>
> I am looking to build a Helical antenna for the 70cm Band. I am
> considering the plans for such an antenna from the 2010 edition of the ARRL
> Satellite Handbook. The plans call for a 235 cm (7' 8") long, 2.5 cm (1")
> diameter center support made of either a wooden dowel which has been
> treated or a fiberglass tube. It also requires multiple 7.6 cm (3")
> spacers for the helical element.
>
> My question is would fiberglass rods made of "Isophthlic Polyester Resin"
> be a good choice of material at UHF frequencies?
> I hesitate to use treated wood because I plan to mount this on the top of a
> 15 meter high tower and it isn't very accessible.
>
> Thanks
>
> Rolf NR0T
> [EN34]
> _______________________________________________
> 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: 9
Date: Mon, 13 May 2013 19:30:33 -0700
From: Greg D <ko6th.greg@xxxxx.xxx>
To: Rolf Krogstad <rolf.krogstad@xxxxx.xxx>
Cc: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Re: Helical Antenna on 70 cm
Message-ID: <5191A1C9.1080709@xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi Rolf,
My understanding is that the material used for center pole in a helix
doesn't affect the antenna dimensions or performance much at all. So,
feel free to use whatever material you have handy that will work
mechanically and environmentally (e.g. ice load and sun exposure). I've
never made a helix for 70cm, but that's about a low a frequency as I'd
consider. They get kind of large and unwieldy as you go down in
frequency, and a 6" coil on a 7' boom would be pushing it for me. A
crossed yagi could be mechanically easier to build, and, to Bob's
point, you could make it run either polarity.
Good luck,
Greg KO6TH
Rolf Krogstad wrote:
> I am new to satellites and new to the design requirements for UHF and am
> looking for advice.
>
> I am looking to build a Helical antenna for the 70cm Band. I am
> considering the plans for such an antenna from the 2010 edition of the ARRL
> Satellite Handbook. The plans call for a 235 cm (7' 8") long, 2.5 cm (1")
> diameter center support made of either a wooden dowel which has been
> treated or a fiberglass tube. It also requires multiple 7.6 cm (3")
> spacers for the helical element.
>
> My question is would fiberglass rods made of "Isophthlic Polyester Resin"
> be a good choice of material at UHF frequencies?
> I hesitate to use treated wood because I plan to mount this on the top of a
> 15 meter high tower and it isn't very accessible.
>
> Thanks
>
> Rolf NR0T
> [EN34]
> _______________________________________________
> 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: 10
Date: Mon, 13 May 2013 19:33:08 -0700
From: Greg D <ko6th.greg@xxxxx.xxx>
To: Rolf Krogstad <rolf.krogstad@xxxxx.xxx>
Cc: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Re: Helical Antenna on 70 cm
Message-ID: <5191A264.1090506@xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi Rolf,
I don't believe that's possible. It would be like asking for a screw
that can be turned in either direction. L / R switching is done by
switching between two antennas.
Greg KO6TH
Rolf Krogstad wrote:
> Thanks, Bob.
>
> Is there a commercial yagi available for 435 MHz which is R-L switchable?
>
> Rolf NR0T
>
>
> On Mon, May 13, 2013 at 8:21 PM, Bob- W7LRD<w7lrd@xxxxxxx.xxx> wrote:
>
>> the helix is a nice antenna...however...once wound for either RHCP or LHCP
>> there's no going back. So switching from R to L or L to R is out of the
>> question. Unless of course the chosen polarity is always compatible with
>> the satellite in use. Unless you have L and a R helix and switch between
>> them, that can get a "little" involved. Many times it is
>> very convenient to be able to switch between L or R during a pass, at times
>> it can make the contact happen. This is of course is easy with a L/R CP
>> yagi. I have used a helix for L band (1.2ghz ) as well as feeds for a
>> 2.4ghz dish. They are a fine antenna with a fair amount of bandwidth. For
>> a 16+ turn helix I have used stainless steel "U" channel for the center
>> support. If Clair, VE3NPC is listening, he's the resident helix guy.
>> Just my opinion, your mileage may differ.
>> 73 Bob W7LRD
>> Seattle
>>
>> ------------------------------
>> *From: *"Rolf Krogstad"<rolf.krogstad@xxxxx.xxx>
>> *To: *amsat-bb@xxxxx.xxx
>> *Sent: *Monday, May 13, 2013 9:22:57 AM
>> *Subject: *[amsat-bb] Helical Antenna on 70 cm
>>
>>
>> I am new to satellites and new to the design requirements for UHF and am
>> looking for advice.
>>
>> I am looking to build a Helical antenna for the 70cm Band. I am
>> considering the plans for such an antenna from the 2010 edition of the ARRL
>> Satellite Handbook. The plans call for a 235 cm (7' 8") long, 2.5 cm (1")
>> diameter center support made of either a wooden dowel which has been
>> treated or a fiberglass tube. It also requires multiple 7.6 cm (3")
>> spacers for the helical element.
>>
>> My question is would fiberglass rods made of "Isophthlic Polyester Resin"
>> be a good choice of material at UHF frequencies?
>> I hesitate to use treated wood because I plan to mount this on the top of a
>> 15 meter high tower and it isn't very accessible.
>>
>> Thanks
>>
>> Rolf NR0T
>> [EN34]
>> _______________________________________________
>> 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
>>
> _______________________________________________
> 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: Tue, 14 May 2013 02:43:41 +0000
From: Jim Jerzycke <kq6ea@xxxxxxx.xxx>
To: Rolf Krogstad <rolf.krogstad@xxxxx.xxx>
Cc: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Re: Helical Antenna on 70 cm
Message-ID: <5191A4DD.5010400@xxxxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
M2 makes one, and I think Gulf Alpha antennas has one.
73, Jim KQ6EA
On 05/14/2013 02:04 AM, Rolf Krogstad wrote:
> Thanks, Bob.
>
> Is there a commercial yagi available for 435 MHz which is R-L switchable?
>
> Rolf NR0T
>
>
> On Mon, May 13, 2013 at 8:21 PM, Bob- W7LRD <w7lrd@xxxxxxx.xxx> wrote:
>
>> the helix is a nice antenna...however...once wound for either RHCP or LHCP
>> there's no going back. So switching from R to L or L to R is out of the
>> question. Unless of course the chosen polarity is always compatible with
>> the satellite in use. Unless you have L and a R helix and switch between
>> them, that can get a "little" involved. Many times it is
>> very convenient to be able to switch between L or R during a pass, at times
>> it can make the contact happen. This is of course is easy with a L/R CP
>> yagi. I have used a helix for L band (1.2ghz ) as well as feeds for a
>> 2.4ghz dish. They are a fine antenna with a fair amount of bandwidth. For
>> a 16+ turn helix I have used stainless steel "U" channel for the center
>> support. If Clair, VE3NPC is listening, he's the resident helix guy.
>> Just my opinion, your mileage may differ.
>> 73 Bob W7LRD
>> Seattle
>>
>> ------------------------------
>> *From: *"Rolf Krogstad" <rolf.krogstad@xxxxx.xxx>
>> *To: *amsat-bb@xxxxx.xxx
>> *Sent: *Monday, May 13, 2013 9:22:57 AM
>> *Subject: *[amsat-bb] Helical Antenna on 70 cm
>>
>>
>> I am new to satellites and new to the design requirements for UHF and am
>> looking for advice.
>>
>> I am looking to build a Helical antenna for the 70cm Band. I am
>> considering the plans for such an antenna from the 2010 edition of the ARRL
>> Satellite Handbook. The plans call for a 235 cm (7' 8") long, 2.5 cm (1")
>> diameter center support made of either a wooden dowel which has been
>> treated or a fiberglass tube. It also requires multiple 7.6 cm (3")
>> spacers for the helical element.
>>
>> My question is would fiberglass rods made of "Isophthlic Polyester Resin"
>> be a good choice of material at UHF frequencies?
>> I hesitate to use treated wood because I plan to mount this on the top of a
>> 15 meter high tower and it isn't very accessible.
>>
>> Thanks
>>
>> Rolf NR0T
>> [EN34]
>> _______________________________________________
>> 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
>>
> _______________________________________________
> 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: Mon, 13 May 2013 19:52:09 -0700
From: Greg D <ko6th.greg@xxxxx.xxx>
To: M5AKA <m5aka@xxxxx.xx.xx>
Cc: amsat-bb@xxxxx.xxxx Daniel Schultz <n8fgv@xxx.xxx>
Subject: [amsat-bb] Re: ISS HamTV Frequencies
Message-ID: <5191A6D9.3090802@xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
2 mhz? Yeah, that would be tough... Ok, DVB-S it is.
Thanks all for the education. There's a swap meet coming up in a couple
of weeks... Sounds like I have a now have a mission. :-)
Greg KO6TH
M5AKA wrote:
> --- On Mon, 13/5/13, Greg Dolkas<ko6th.greg@xxxxx.xxx> wrote:
>> Is there something about the DVB-S modulation that makes it
>> astoundingly better for this application? For
>> something that is intended to be widely received, they sure
>> are making it difficult...
> DVB-S receivers are in use in hundreds of millions of homes around the
world. Apart from DVB-S2, which is not yet so widespread, I'm not aware of
any other standard that would deliver better performance in a 2 MHz bandwidth.
>
> 73 Trevor M5AKA
>
------------------------------
Message: 13
Date: Mon, 13 May 2013 23:03:51 -0400
From: "Daniel Schultz" <n8fgv@xxx.xxx>
To: Greg D <ko6th.greg@xxxxx.xxx>, M5AKA <m5aka@xxxxx.xx.xx>
Cc: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Re: ISS HamTV Frequencies
Message-ID: <331ReNDcz7360S04.1368500631@xxxxx.xxx.xxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
I would research the matter carefully before buying any equipment, does anyone
in the ISS HamTV group have any data on which DVB-S receivers will work? This
is pretty much beyond what the gear was designed for!
Dan Schultz N8FGV
------ Original Message ------
Received: Mon, 13 May 2013 10:52:22 PM EDT
From: Greg D <ko6th.greg@xxxxx.xxx>
To: M5AKA <m5aka@xxxxx.xx.xx>Cc: Daniel Schultz <n8fgv@xxx.xxx>,
amsat-bb@xxxxx.xxx
Subject: Re: [amsat-bb] Re: ISS HamTV Frequencies
> 2 mhz? Yeah, that would be tough... Ok, DVB-S it is.
>
> Thanks all for the education. There's a swap meet coming up in a couple
> of weeks... Sounds like I have a now have a mission. :-)
>
> Greg KO6TH
------------------------------
Message: 14
Date: Tue, 14 May 2013 06:49:15 +0200
From: "i8cvs" <domenico.i8cvs@xxx.xx>
To: "Rolf Krogstad" <rolf.krogstad@xxxxx.xxx>, "Amsat - BBs"
<amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: Helical Antenna on 70 cm
Message-ID: <000101ce505e$d0a75c20$0401a8c0@xxxxxx>
Content-Type: text/plain; charset="iso-8859-1"
Hi Rolf, NR0T
The fiberglass rods made of "Isophthlic Polyester Resin"
is a good choice of material at UHF frequencies and it is
the material I have used for my RHCP 10 turns Helical
Antenna for 435 MHz in use on the roof since 1976
beginning from OSCAR-8 Mode-J and actually working
since than for VO-52
In a separate email I have sent to you a zipped file with all
mechanical drawings to built it in all details.If you like to
increase the numbar of turns from 10 to 15 no problems
because the only adjustement required is to change a little
bit step by step the distance between the reflector and the
first turn in order to get the lower possible VSWR.
In my Helical Antenna the boom is a very hard plastic tube
called Moplen, outside diameter 42 mm ,inside diameter
34 mm and so 5,5 mm thick.
The turns of the Helical are made with 8 mm diameter
solid annealed aluminum rod and the spacers between
the turns are 8 mm outside diameter fiber glass rods.
For best performance I have mounted the supporting steel
horizontal harm on the rear of reflector in order to prevent
interactions between the EM field of the turns and the
mechanical metallic support.
In order to balance the weight of the Antenna I have mounted
in the rear of reflector a round counterweight made of lead.
Have fun !
73" de
i8CVS Domenico
----- Original Message -----
From: "Rolf Krogstad" <rolf.krogstad@xxxxx.xxx>
To: <amsat-bb@xxxxx.xxx>
Sent: Monday, May 13, 2013 6:22 PM
Subject: [amsat-bb] Helical Antenna on 70 cm
> I am new to satellites and new to the design requirements for UHF and am
> looking for advice.
>
> I am looking to build a Helical antenna for the 70cm Band. I am
> considering the plans for such an antenna from the 2010 edition of the
ARRL
> Satellite Handbook. The plans call for a 235 cm (7' 8") long, 2.5 cm (1")
> diameter center support made of either a wooden dowel which has been
> treated or a fiberglass tube. It also requires multiple 7.6 cm (3")
> spacers for the helical element.
>
> My question is would fiberglass rods made of "Isophthlic Polyester Resin"
> be a good choice of material at UHF frequencies?
> I hesitate to use treated wood because I plan to mount this on the top of
a
> 15 meter high tower and it isn't very accessible.
>
> Thanks
>
> Rolf NR0T
> [EN34]
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
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------------------------------
_______________________________________________
Sent via amsat-bb@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
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End of AMSAT-BB Digest, Vol 8, Issue 156
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