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CX2SA > SATDIG 06.03.20 20:40l 799 Lines 27007 Bytes #999 (0) @ WW
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Sent: 200306/1833Z @:CX2SA.SAL.URY.SOAM #:26307 [Salto] FBB7.00e $:AMSATBB1570
From: CX2SA@CX2SA.SAL.URY.SOAM
To : SATDIG@WW
Today's Topics:
1. Where best to purchase LMR-240UF in the US? (Hans BX2ABT)
2. Re: sequencer (MICHAEL WILLIAMS)
3. Re: Where best to purchase LMR-240UF in the US? (Rolf Krogstad)
4. Re: Where best to purchase LMR-240UF in the US? (Jeff )
5. Re: Where best to purchase LMR-240UF in the US? (Scott)
6. Re: Sequencer advice needed (Roger - W7TZ)
7. Re: Sequencer advice needed (John Kludt)
8. WD9EWK @ DM51/DM52 next Friday (13 March 2020)
(Patrick STODDARD (WD9EWK/VA7EWK))
9. Re: Where best to purchase LMR-240UF in the US? (Mike Sprenger)
10. Center of the rotator (Thomas Schaefer)
11. Re: Where best to purchase LMR-240UF in the US? (Thomas Schaefer)
12. Re: Center of the rotator (Mark D. Johns)
----------------------------------------------------------------------
Message: 1
Date: Fri, 6 Mar 2020 20:26:08 +0800
From: Hans BX2ABT <hans.bx2abt@???.?????.???>
To: AMSAT <amsat-bb@?????.???>
Subject: [amsat-bb] Where best to purchase LMR-240UF in the US?
Message-ID: <9b996c89-469a-a4d5-51e2-6ff98e63ac38@???.?????.???>
Content-Type: text/plain; charset=utf-8; format=flowed
As in title. Need some 200 feet. Mail order is fine, delivery in
Houston. Will be hand delivered to me in Taiwan, because I can't get the
stuff locally. Cheers --Hans
------------------------------
Message: 2
Date: Fri, 6 Mar 2020 07:58:53 -0500 (EST)
From: MICHAEL WILLIAMS <k9qho67622@???????.???>
To: hans.bx2abt@???.?????.???? amsat-bb@?????.???
Subject: Re: [amsat-bb] sequencer
Message-ID: <261434636.638594.1583499533733@???????.???????.???>
Content-Type: text/plain; charset=UTF-8
Check out W1GHZ's "A Simple, Yet Fool-Resistant Sequencer" at
http://www.w1ghz.org/small_proj/Simple_yet_Fool-Resistant_Sequencer_Rev_B.pdf
GL, K9QHO
------------------------------
Message: 3
Date: Fri, 6 Mar 2020 07:44:24 -0600
From: Rolf Krogstad <rolf.krogstad@?????.???>
To: Hans BX2ABT <hans.bx2abt@???.?????.???>
Cc: AMSAT <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Where best to purchase LMR-240UF in the US?
Message-ID:
<CAJJyj=bqU-QOLaYfH7_3qGs1bOM2ScFZZjup1yu=FFC2RcoPjw@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
DX Engineering. Great service. $1.08 per foot.
https://www.dxengineering.com/parts/tmv-lmr-240ultra
73
Rolf NR0T
EN34
On Fri, Mar 6, 2020, 6:45 AM Hans BX2ABT via AMSAT-BB <amsat-bb@?????.???>
wrote:
> As in title. Need some 200 feet. Mail order is fine, delivery in
> Houston. Will be hand delivered to me in Taiwan, because I can't get the
> stuff locally. Cheers --Hans
>
> _______________________________________________
> Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
> expressed
> are solely those of the author, and do not reflect the official views of
> AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
>
------------------------------
Message: 4
Date: Fri, 6 Mar 2020 09:14:56 -0500
From: "Jeff " <kb2mjeff@???.???>
To: <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Where best to purchase LMR-240UF in the US?
Message-ID: <02a101d5f3c1$9e5d73e0$db185ba0$@???.???>
Content-Type: text/plain; charset="us-ascii"
Or here, 200 foot at .97 a foot.
https://www.rfparts.com/lmr240uf.html
Also look around on Amazon for a Chinese copy. I tried some and it was good
quality...
73 Jeff kb2m
-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces@?????.???> On Behalf Of Rolf Krogstad via
AMSAT-BB
Sent: Friday, March 06, 2020 8:44
To: Hans BX2ABT <hans.bx2abt@???.?????.???>
Cc: AMSAT <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Where best to purchase LMR-240UF in the US?
DX Engineering. Great service. $1.08 per foot.
https://www.dxengineering.com/parts/tmv-lmr-240ultra
73
Rolf NR0T
EN34
On Fri, Mar 6, 2020, 6:45 AM Hans BX2ABT via AMSAT-BB <amsat-bb@?????.???>
wrote:
> As in title. Need some 200 feet. Mail order is fine, delivery in
> Houston. Will be hand delivered to me in Taiwan, because I can't get
> the stuff locally. Cheers --Hans
>
> _______________________________________________
> Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership.
> Opinions expressed are solely those of the author, and do not reflect
> the official views of AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
>
_______________________________________________
Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available to all
interested persons worldwide without requiring membership. Opinions
expressed are solely those of the author, and do not reflect the official
views of AMSAT-NA.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 5
Date: Fri, 6 Mar 2020 11:42:35 -0500
From: Scott <scott23192@?????.???>
To: AMSAT <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Where best to purchase LMR-240UF in the US?
Message-ID:
<CAJCSnOZgmntj9ji7yKjekxxprJhggGz7UXoZO3GeuG8oN0neZg@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
I have always been very pleased with:
https://usacoax.com/custom.html
-Scott, K4KDR
=================================
On Fri, Mar 6, 2020 at 7:45 AM Hans BX2ABT via AMSAT-BB <amsat-bb@?????.???>
wrote:
> As in title. Need some 200 feet. Mail order is fine, delivery in
> Houston. Will be hand delivered to me in Taiwan, because I can't get the
> stuff locally. Cheers --Hans
>
------------------------------
Message: 6
Date: Fri, 6 Mar 2020 08:45:33 -0800
From: Roger - W7TZ <ai7rogerroger@?????.???>
To: Hans BX2ABT <hans.bx2abt@???.?????.???>
Cc: AMSAT <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Sequencer advice needed
Message-ID:
<CAEahN0+2=A_KKhEjQhCdt6HWrnuSaQiczFDUfqpHxUeqWNRo0w@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
I've used the W6PQL (built and tested) unit for 6m and 1.25m very
successfully for several years.
73, Roger
W7TZ
CN83ia
On Fri, Mar 6, 2020 at 4:26 AM Hans BX2ABT via AMSAT-BB <amsat-bb@?????.???>
wrote:
> I haven't worked with sequencers before as all my LNAs and SDRs have
> been used for receive only. But now that I have a Airspy HF+ I want to
> get going with APRS on 145.825 and use this on HF as well. So receiving
> with the SDR, transmitting with a transceiver. I also want to experiment
> with LNAs, so another reason to use a sequencer. I did a lot of
> googling, learned some, but still not sure what I need to look out for
> when buying one. I prefer a kit or assembled product as a first try.
>
> Below is a list of what I found on line. From a distance the VHF Design
> is cheap and has detailed information, so I am leaning towards
> purchasing that. Later, for a DIY project, I like the OZ1BXM design
> because it uses an Arduino for control, which brings some flexiblity.
>
> Can you all please give me some input on what to look for in sequencers
> or comment on the choices below? Any other kits/assemblies I have missed
> and should be considered? Cheers,
>
> Hans
> BX2ABT
>
>
>
> Minikits from Austalia's EME166: AU$45 (=US$27.75)
>
> https://www.minikits.com.au/Sequencer?search=Sequencer
>
> This is the only one that indicates a frequency range: 28 to 500 MHz, so
> this will cover the 2m band, but not HF. Also RF input is 4 Watts
> maximum, which seems low, so how is this usable?
>
>
>
> W6PQL's sequencer (US$20 for kit, US$37.50 assembled)
>
> http://www.w6pql.com/relay_sequencer.htm
>
> No info on frequency range or input power. Not much info on the website.
>
>
>
> VHF Design (US$20 assembled)
>
> https://vhfdesign.com/other/sequencer-pcb.html
>
> Website has good information, diagrams and PCB layouts. Again no info on
> frequency range, etc.
>
>
>
> Downeast Microwave (US$25~80)
>
>
> https://www.downeastmicrowave.com/searchresults.asp?Search=sequencer&Submit=
>
> 3 and 4 step sequencers both in solid state and with relays based on a
> design by W5LUA. Which better: solid state or relays? Little indept info.
>
>
>
> G3SEK - (DIY)
>
> http://www.ifwtech.co.uk/g3sek/dx-book/sequencer/
>
> Basically only a schematic, so need to build it from the ground up.
>
>
>
> OZ1BXM (DIY)
>
> http://oz1bxm.dk/seq/sequencer.html
>
> Another DIY project based on the W6PLQ design. This uses an Arduino as
> MCU, so should be flexible. No kits and no PCB designs.
>
>
>
> SM2CEW (DIY)
>
> http://sm2cew.com/sequencer/sequencer.html
>
> This one looks very simple to make with very few components. It was
> designed for HF, so will it work on VHF?
>
>
> _______________________________________________
> Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
> expressed
> are solely those of the author, and do not reflect the official views of
> AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
>
------------------------------
Message: 7
Date: Fri, 6 Mar 2020 12:08:20 -0500
From: John Kludt <johnnykludt@?????.???>
To: Roger - W7TZ <ai7rogerroger@?????.???>
Cc: AMSAT <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Sequencer advice needed
Message-ID:
<CABsMmtTUNxYZJEuNc9yUvTOVC6WfDVYHh+t7VhAabxxiK7aJJQ@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Roger,
I am a little confused by your comment on frequency range and power as
those are characterists of the relays themselves and not the sequencer.
The purpose of the sequencer is to switch equipment and feedlines from
receive to transmit and back in a orderly sequence such that RF is the last
thing applied on transmit and the first thing removed on receive. As such
a sequencer is an electrical device and not a RF device.
On my 1296 system I use the Demi solid state sequencer. Step 1 removes
preamp power. Step 2 switches the preamp out of line by activating two
coaxial relays (where I spent real money!). Step 3 grounds the PTT on the
W6PQL power amplifier and then Step 4 grounds the PTT on the transceiver
and applies RF. There are other switching schemes but this is a fairly
common one.
Hope that helps.
Johnny
On Fri, Mar 6, 2020, 11:50 Roger - W7TZ via AMSAT-BB <amsat-bb@?????.???>
wrote:
> I've used the W6PQL (built and tested) unit for 6m and 1.25m very
> successfully for several years.
>
> 73, Roger
> W7TZ
> CN83ia
>
>
> On Fri, Mar 6, 2020 at 4:26 AM Hans BX2ABT via AMSAT-BB <
> amsat-bb@?????.???>
> wrote:
>
> > I haven't worked with sequencers before as all my LNAs and SDRs have
> > been used for receive only. But now that I have a Airspy HF+ I want to
> > get going with APRS on 145.825 and use this on HF as well. So receiving
> > with the SDR, transmitting with a transceiver. I also want to experiment
> > with LNAs, so another reason to use a sequencer. I did a lot of
> > googling, learned some, but still not sure what I need to look out for
> > when buying one. I prefer a kit or assembled product as a first try.
> >
> > Below is a list of what I found on line. From a distance the VHF Design
> > is cheap and has detailed information, so I am leaning towards
> > purchasing that. Later, for a DIY project, I like the OZ1BXM design
> > because it uses an Arduino for control, which brings some flexiblity.
> >
> > Can you all please give me some input on what to look for in sequencers
> > or comment on the choices below? Any other kits/assemblies I have missed
> > and should be considered? Cheers,
> >
> > Hans
> > BX2ABT
> >
> >
> >
> > Minikits from Austalia's EME166: AU$45 (=US$27.75)
> >
> > https://www.minikits.com.au/Sequencer?search=Sequencer
> >
> > This is the only one that indicates a frequency range: 28 to 500 MHz, so
> > this will cover the 2m band, but not HF. Also RF input is 4 Watts
> > maximum, which seems low, so how is this usable?
> >
> >
> >
> > W6PQL's sequencer (US$20 for kit, US$37.50 assembled)
> >
> > http://www.w6pql.com/relay_sequencer.htm
> >
> > No info on frequency range or input power. Not much info on the website.
> >
> >
> >
> > VHF Design (US$20 assembled)
> >
> > https://vhfdesign.com/other/sequencer-pcb.html
> >
> > Website has good information, diagrams and PCB layouts. Again no info on
> > frequency range, etc.
> >
> >
> >
> > Downeast Microwave (US$25~80)
> >
> >
> >
> https://www.downeastmicrowave.com/searchresults.asp?Search=sequencer&Submit=
> >
> > 3 and 4 step sequencers both in solid state and with relays based on a
> > design by W5LUA. Which better: solid state or relays? Little indept info.
> >
> >
> >
> > G3SEK - (DIY)
> >
> > http://www.ifwtech.co.uk/g3sek/dx-book/sequencer/
> >
> > Basically only a schematic, so need to build it from the ground up.
> >
> >
> >
> > OZ1BXM (DIY)
> >
> > http://oz1bxm.dk/seq/sequencer.html
> >
> > Another DIY project based on the W6PLQ design. This uses an Arduino as
> > MCU, so should be flexible. No kits and no PCB designs.
> >
> >
> >
> > SM2CEW (DIY)
> >
> > http://sm2cew.com/sequencer/sequencer.html
> >
> > This one looks very simple to make with very few components. It was
> > designed for HF, so will it work on VHF?
> >
> >
> > _______________________________________________
> > Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
> > to all interested persons worldwide without requiring membership.
> Opinions
> > expressed
> > are solely those of the author, and do not reflect the official views of
> > AMSAT-NA.
> > Not an AMSAT-NA member? Join now to support the amateur satellite
> program!
> > Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
> >
> _______________________________________________
> Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
> expressed
> are solely those of the author, and do not reflect the official views of
> AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
>
------------------------------
Message: 8
Date: Fri, 6 Mar 2020 17:12:50 +0000
From: "Patrick STODDARD (WD9EWK/VA7EWK)" <amsat-bb@??????.???>
To: AMSAT <amsat-bb@?????.???>
Subject: [amsat-bb] WD9EWK @ DM51/DM52 next Friday (13 March 2020)
Message-ID:
<CAN6TEUfZTR0MPt0WPdEnnfHu+uaBWzEaOejx=JYQZWAsk-_cTg@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Hi!
I will head to the DM51/DM52 grid boundary in southeastern Arizona next
Friday (13 March 2020), where I plan to spend a few hours working
various satellite passes. I hope to be on the air from DM51/DM52 for
the AO-92 pass just after 1700 UTC, but might be on earlier passes if
traffic through Phoenix and Tucson - and the weather - cooperates. I
will park at a spot I have visited many times over the years, west of
US-191 and south of I-10, near the town of Sunsites in Arizona's
Cochise County.
During my time out at DM51/DM52, I will post updates on my @??????
Twitter account. These updates are visible in a web browser without a
Twitter account at:
http://twitter.com/WD9EWK
In addition, I will run APRS as WD9EWK-9 during that day. My travels
should show up online at sites like:
http://aprs.fi/WD9EWK-9
All QSOs will be uploaded to Logbook of the World. If anyone wishes to
receive a QSL card confirming a QSO with WD9EWK at DM51/DM52, please
e-mail me directly with the QSO details. No need to first send me a
card or an SASE. If you're in the log, I will send a QSL card.
This is not the only time I might be in this area over the next couple
of months. I have two other trips between late March and early May
which may allow me to visit other grid boundaries in southeastern
Arizona or even southwestern New Mexico. Stay tuned... :-)
73!
Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/
Twitter: @?????? or http://twitter.com/WD9EWK
------------------------------
Message: 9
Date: Fri, 6 Mar 2020 12:24:33 -0500
From: Mike Sprenger <mikesprenger@?????.???>
To: Hans BX2ABT <hans.bx2abt@???.?????.???>
Cc: AMSAT <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Where best to purchase LMR-240UF in the US?
Message-ID: <848C4EB2-E0C3-4443-9298-CD3EDA2DE395@?????.???>
Content-Type: text/plain; charset=utf-8
No affiliation just a happy customer.
I use these guys plus they will connector the cables for you (not free but
great work).
https://rfconnection.com/belden-9913f7-cable/coaxial-cable/
LMR-240UF
$ .86/FT
$80.00/100?
.044 Cu stranded center conductor with micro-cell foam dielectric & type
IIIA jacket. Nominal impedance 50 Ohms; velocity of propagation 83%; Outer
diameter .240; 100% Al Mylar tape & 95% tinned Cu braid.
REAL TIMES MICROWAVE CABLE
Thanks,
Mike
Sent from my iPhone
> On Mar 6, 2020, at 7:45 AM, Hans BX2ABT via AMSAT-BB <amsat-bb@?????.???>
wrote:
>
> ?As in title. Need some 200 feet. Mail order is fine, delivery in Houston.
Will be hand delivered to me in Taiwan, because I can't get the stuff
locally. Cheers --Hans
>
> _______________________________________________
> Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
expressed
> are solely those of the author, and do not reflect the official views of
AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 10
Date: Fri, 6 Mar 2020 12:49:24 -0500
From: Thomas Schaefer <ny4i@????.???>
To: amsat-bb <amsat-bb@?????.???>
Subject: [amsat-bb] Center of the rotator
Message-ID: <47C7D44C-F50E-4473-92D6-2C8E4DF59B7E@????.???>
Content-Type: text/plain; charset=utf-8
Hello all. Please forgive the novice question but I am new to dealing with
Az/El rotator systems for satellites (always been the Armstrong method).
I am finishing up the planning for my rotators. On my bench, I have my Az
rotator and my elevations rotator (separate units ?both AlfaSpids). I am
using a Green Heron RT21 AzEl controller.
I have PSTRotator in between SatPC32 and the Green Heron since SatPC32 does
not control the GH AzEl directly.
When I was testing, I went though a pass and when the Azimuth direction was
0, the rotator spun all away around since 0 was the bottom. That is no doubt
a configuration point but it brings me to my question.
When I have used various rotor controllers for HF beams, 180 degrees is
always the bottom which works for us in the northern Hemisphere. But with
the current fleet of workable satellites, is there a direction that makes
more sense to use at the ?bottom? of the rotator? I can rotate the AlfaSpid
more than 360 degrees allowing for the coax loop. Is that the generally
preferred way for maximum flexibility if one?s rotor supports it? Put
another way, if I pick 180 as the ?bottom?, will I have as many passes that
the rotator will have to turn all the way around to get from 179 degrees to
181 degrees as I would have to go from 359 degrees to 1 degree?
I am also using the Az rotator for a 6m beam so the usual sweep of 180 to
180 in a continuous arc is desirable but I was curious if I should allow an
extra 90 degrees (to 470) for flexibility. The Green Heron will take care of
not going too far from where it is programmed even though the AlfaSpid does
not have limit switches in the Az rotator (but does in the elevation rotator).
I hope that makes sense.
Thanks,
Tom NY4I
Tom Schaefer, NY4I
Blog: www.ny4i.com
Madeira Beach, FL (Grid: EL87ot)
------------------------------
Message: 11
Date: Fri, 6 Mar 2020 13:08:16 -0500
From: Thomas Schaefer <ny4i@????.???>
To: Mike Sprenger <mikesprenger@?????.???>
Cc: AMSAT <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Where best to purchase LMR-240UF in the US?
Message-ID: <1CD4D309-89A1-4304-BF73-49E222CC5C12@????.???>
Content-Type: text/plain; charset=utf-8
Get yourself a Tessco Account (tessco.com). It is free and they sell real
LMR-240UF for $0.83 a foot. You do pay shipping and tax but still cheaper
than 1.08 a foot with DXEngineering?s free shipping. I buy all my cables and
connectors from Tessco. They carry the full RF Parts connector line as well
as real Times Microwave connectors (which I use for tower side connectors).
They have a very useful catalog system on their website too.
The RF Connection price is quite good at $0.86 a foot as that is just 3
cents more than Tessco (you still pay shipping).
Tom Schaefer, NY4I
Blog: www.ny4i.com
Madeira Beach, FL (Grid: EL87ot)
> On Mar 6, 2020, at 12:24 PM, Mike Sprenger via AMSAT-BB
<amsat-bb@?????.???> wrote:
>
> No affiliation just a happy customer.
>
> I use these guys plus they will connector the cables for you (not free but
great work).
>
> https://rfconnection.com/belden-9913f7-cable/coaxial-cable/
>
> LMR-240UF
> $ .86/FT
> $80.00/100?
>
> .044 Cu stranded center conductor with micro-cell foam dielectric & type
IIIA jacket. Nominal impedance 50 Ohms; velocity of propagation 83%; Outer
diameter .240; 100% Al Mylar tape & 95% tinned Cu braid.
>
> REAL TIMES MICROWAVE CABLE
>
>
>
> Thanks,
> Mike
>
> Sent from my iPhone
>
>> On Mar 6, 2020, at 7:45 AM, Hans BX2ABT via AMSAT-BB <amsat-bb@?????.???>
wrote:
>>
>> ?As in title. Need some 200 feet. Mail order is fine, delivery in
Houston. Will be hand delivered to me in Taiwan, because I can't get the
stuff locally. Cheers --Hans
>>
>> _______________________________________________
>> Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
>> to all interested persons worldwide without requiring membership.
Opinions expressed
>> are solely those of the author, and do not reflect the official views of
AMSAT-NA.
>> Not an AMSAT-NA member? Join now to support the amateur satellite program!
>> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
> _______________________________________________
> Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
expressed
> are solely those of the author, and do not reflect the official views of
AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 12
Date: Fri, 6 Mar 2020 12:24:12 -0600
From: "Mark D. Johns" <mjohns+K0JM@??????.???>
To: Thomas Schaefer <ny4i@????.???>
Cc: amsat-bb <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Center of the rotator
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For satellites, there's no perfect direction for the azimuth stop,
because most LEOs in near-polar orbits tend to pass along an arc to
the east or or an arc to the west, and only relatively rarely right
overhead.
For me, living in Minneapolis, I use a north stop because a lot of
things happen south of me. For example, passes of CAS-4A and CAS-4B
almost always go from west-southwest, through south, and on to the
southeast from my QTH. A south stop would require a flip or a complete
turn for every CAS-4x pass.
For you, down in Florida, a 180 degree stop may be of slight
advantage. You'd probably have to do a plot of several birds you plan
to use over a period of a couple weeks, and see how many of those
passes would require flipping.
--
Mark D. Johns, K?JM
AMSAT Ambassador & News Service Editor
Brooklyn Park, MN USA EN35hd
-----------------------------------------------
"Heaven goes by favor; if it went by merit,
you would stay out and your dog would go in."
---Mark Twain
On Fri, Mar 6, 2020 at 11:50 AM Thomas Schaefer via AMSAT-BB
<amsat-bb@?????.???> wrote:
>
> Hello all. Please forgive the novice question but I am new to dealing with
Az/El rotator systems for satellites (always been the Armstrong method).
>
> I am finishing up the planning for my rotators. On my bench, I have my Az
rotator and my elevations rotator (separate units ?both AlfaSpids). I am
using a Green Heron RT21 AzEl controller.
>
> I have PSTRotator in between SatPC32 and the Green Heron since SatPC32
does not control the GH AzEl directly.
>
> When I was testing, I went though a pass and when the Azimuth direction
was 0, the rotator spun all away around since 0 was the bottom. That is no
doubt a configuration point but it brings me to my question.
>
> When I have used various rotor controllers for HF beams, 180 degrees is
always the bottom which works for us in the northern Hemisphere. But with
the current fleet of workable satellites, is there a direction that makes
more sense to use at the ?bottom? of the rotator? I can rotate the AlfaSpid
more than 360 degrees allowing for the coax loop. Is that the generally
preferred way for maximum flexibility if one?s rotor supports it? Put
another way, if I pick 180 as the ?bottom?, will I have as many passes that
the rotator will have to turn all the way around to get from 179 degrees to
181 degrees as I would have to go from 359 degrees to 1 degree?
>
> I am also using the Az rotator for a 6m beam so the usual sweep of 180 to
180 in a continuous arc is desirable but I was curious if I should allow an
extra 90 degrees (to 470) for flexibility. The Green Heron will take care of
not going too far from where it is programmed even though the AlfaSpid does
not have limit switches in the Az rotator (but does in the elevation rotator).
>
> I hope that makes sense.
>
> Thanks,
>
> Tom NY4I
> Tom Schaefer, NY4I
> Blog: www.ny4i.com
> Madeira Beach, FL (Grid: EL87ot)
>
>
>
>
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Not an AMSAT member? Join now to support the amateur satellite program!
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End of AMSAT-BB Digest, Vol 15, Issue 70
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