Discussion:
beginner question re: uplink power
(too old to reply)
12.01
2008-10-19 05:30:09 UTC
Permalink
hello,

I have a beginner question. I am in the process of setting up my first
satellite station. My initial investment is minimal and I have chosen
to start out with a pair of 2m and 70cm omni antennas on the roof. To
help out a bit I am also adding a mast mount preamp on each antenna. To
protect the preamps they will be switched out of line by a RF sense
switch (one for each amp). For reference the two preamps and the pair
of RF switches are all made by Ramsey (I know there are better preamps,
but not available in my current budget). I am keeping this initial
adventure limited to the LEOs (and ISS, etc.).

_The question: _ When I assemble the RF switches I must choose a RF
range for the switch to work within. The range is determined by the
choice of a specific resistor. The default three ranges suggested are
0-10 watts, 10-30 watts, and 30-100 watts. I would be able to change
the range later but it would require removing the unit from the mast.

So... not having any experience (yet),_ what uplink power range is
recommend for non-gain antennas?_ Is there one range that should cover
the LEOs? If not, how much should I expect the required uplink power
needs to vary across various satellites? Is it different for each band?
I have read that it is always best to never be louder than the beacon
and that's fine. I'm just needing to know where to start off my
hardware choices.

Thanks in advance for any help from you folks with the know-how. I look
forward to a qso with you.

.paul ac0z
corner5
2008-10-19 05:41:46 UTC
Permalink
hello,

I have a beginner question. I am in the process of setting up my first
satellite station. My initial investment is minimal and I have chosen
to start out with a pair of 2m and 70cm omni antennas on the roof. To
help out a bit I am also adding a mast mount preamp on each antenna. To
protect the preamps they will be switched out of line by a RF sense
switch (one for each amp). For reference the two preamps and the pair
of RF switches are all made by Ramsey (I know there are better preamps,
but not available in my current budget). I am keeping this initial
adventure limited to the LEOs (and ISS, etc.).

_The question: _ When I assemble the RF switches I must choose a RF
range for the switch to work within. The range is determined by the
choice of a specific resistor. The default three ranges suggested are
0-10 watts, 10-30 watts, and 30-100 watts. I would be able to change
the range later but it would require removing the unit from the mast.

So... not having any experience (yet),_ what uplink power range is
recommend for non-gain antennas?_ Is there one range that should cover
the LEOs? If not, how much should I expect the required uplink power
needs to vary across various satellites? Is it different for each band?
I have read that it is always best to never be louder than the beacon
and that's fine. I'm just needing to know where to start off my
hardware choices.

Thanks in advance for any help from you folks with the know-how. I look
forward to a qso with you.

.paul ac0z
Roger Kolakowski
2008-10-19 14:06:16 UTC
Permalink
Post by 12.01
My initial investment is minimal
When I assemble the RF switches I must choose a RF
range....The range is determined by the
choice of a specific resistor. The default three >ranges suggested are
0-10 watts, 10-30 watts, and 30-100 watts.
The answer is actually in what transmitters or power amplifiers are you
planning to use that fit within your budget?

Watts cost money...

With a limited gain omnidirectional you might best aim toward the middle
range but if you are looking at used SSB/CW equipment at 430, many of the
less expensive older radios only ran 10 watts out. Of course a "Linear
Amplifier" for SSB/CW could move you up but is not necessarily inexpensive.

You might want to just accept the fact that you may need to "climb the
tower" again once you settle on your transmitters.

Roger
WA1KAT

Sent: Sunday, October 19, 2008 1:30 AM
Subject: [amsat-bb] beginner question re: uplink power
Post by 12.01
hello,
My initial investment is minimal

When I assemble the RF switches I must choose a RF
range....The range is determined by the
Post by 12.01
choice of a specific resistor. The default three ranges suggested are
0-10 watts, 10-30 watts, and 30-100 watts.
corner5
2008-10-19 17:42:08 UTC
Permalink
Hi Roger,

Thanks very much for the reply. I did forget to mention that I will be
using my Kenwood TS2000 for this purpose. This allows me the full 0-100
watts choice for 2m, and 0-50 watts choice for 70cm. The preamps are
only for receive. The RF switches are between the rig and the preamps
and will bypass the preamps upon transmit. I can start out my RF out
anywhere within the above stated ranges.

Any further thoughts?

.paul
Post by Roger Kolakowski
Post by 12.01
My initial investment is minimal
When I assemble the RF switches I must choose a RF
range....The range is determined by the
choice of a specific resistor. The default three >ranges suggested are
0-10 watts, 10-30 watts, and 30-100 watts.
The answer is actually in what transmitters or power amplifiers are you
planning to use that fit within your budget?
Watts cost money...
With a limited gain omnidirectional you might best aim toward the middle
range but if you are looking at used SSB/CW equipment at 430, many of the
less expensive older radios only ran 10 watts out. Of course a "Linear
Amplifier" for SSB/CW could move you up but is not necessarily inexpensive.
You might want to just accept the fact that you may need to "climb the
tower" again once you settle on your transmitters.
Roger
WA1KAT
Sent: Sunday, October 19, 2008 1:30 AM
Subject: [amsat-bb] beginner question re: uplink power
Post by 12.01
hello,
My initial investment is minimal
When I assemble the RF switches I must choose a RF
range....The range is determined by the
Post by 12.01
choice of a specific resistor. The default three ranges suggested are
0-10 watts, 10-30 watts, and 30-100 watts.
Roger Kolakowski
2008-10-19 19:30:36 UTC
Permalink
I think I would contact Ramsey and see what the resistor selection
limitations are, unless you have a schematic and can determine it from the
design.

Sure enough, if you set it for 10 watts you are going to, some day, put 50
or 100 watts through it in error and I'm assuming if you kill the remote
switching it defaults to receive and therefore doesn't switch the preamp out
resulting in a trip up the tower to fix 2 things.

If you set it for 100 watts, you will someday want to run less and again it
won't key. Same trip up the tower.

Hard wiring, as has been suggested, is your safest choice. As the switch has
the relay in it, maybe Ramsey can tell you where to tap in to directly
switch the sensor.

Nice choice of rig though ;-)

Roger
WA1KAT


----- Original Message -----
From: "corner5" <***@comcast.net>
To: "Roger Kolakowski" <***@aol.com>
Cc: <amsat-***@amsat.org>
Sent: Sunday, October 19, 2008 1:42 PM
Subject: [amsat-bb] Re: beginner question re: uplink power
Post by corner5
Hi Roger,
Thanks very much for the reply. I did forget to mention that I will be
using my Kenwood TS2000 for this purpose. This allows me the full 0-100
watts choice for 2m, and 0-50 watts choice for 70cm. The preamps are
only for receive. The RF switches are between the rig and the preamps
and will bypass the preamps upon transmit. I can start out my RF out
anywhere within the above stated ranges.
Any further thoughts?
.paul
Roger Kolakowski
2008-10-19 19:30:36 UTC
Permalink
I think I would contact Ramsey and see what the resistor selection
limitations are, unless you have a schematic and can determine it from the
design.

Sure enough, if you set it for 10 watts you are going to, some day, put 50
or 100 watts through it in error and I'm assuming if you kill the remote
switching it defaults to receive and therefore doesn't switch the preamp out
resulting in a trip up the tower to fix 2 things.

If you set it for 100 watts, you will someday want to run less and again it
won't key. Same trip up the tower.

Hard wiring, as has been suggested, is your safest choice. As the switch has
the relay in it, maybe Ramsey can tell you where to tap in to directly
switch the sensor.

Nice choice of rig though ;-)

Roger
WA1KAT


----- Original Message -----
From: "corner5" <***@comcast.net>
To: "Roger Kolakowski" <***@aol.com>
Cc: <amsat-***@amsat.org>
Sent: Sunday, October 19, 2008 1:42 PM
Subject: [amsat-bb] Re: beginner question re: uplink power
Post by corner5
Hi Roger,
Thanks very much for the reply. I did forget to mention that I will be
using my Kenwood TS2000 for this purpose. This allows me the full 0-100
watts choice for 2m, and 0-50 watts choice for 70cm. The preamps are
only for receive. The RF switches are between the rig and the preamps
and will bypass the preamps upon transmit. I can start out my RF out
anywhere within the above stated ranges.
Any further thoughts?
.paul
Edward Cole
2008-10-19 17:22:09 UTC
Permalink
Post by 12.01
hello,
I have a beginner question. I am in the process of setting up my first
satellite station. My initial investment is minimal and I have chosen
to start out with a pair of 2m and 70cm omni antennas on the roof. To
help out a bit I am also adding a mast mount preamp on each antenna. To
protect the preamps they will be switched out of line by a RF sense
switch (one for each amp). For reference the two preamps and the pair
of RF switches are all made by Ramsey (I know there are better preamps,
but not available in my current budget). I am keeping this initial
adventure limited to the LEOs (and ISS, etc.).
_The question: _ When I assemble the RF switches I must choose a RF
range for the switch to work within. The range is determined by the
choice of a specific resistor. The default three ranges suggested are
0-10 watts, 10-30 watts, and 30-100 watts. I would be able to change
the range later but it would require removing the unit from the mast.
So... not having any experience (yet),_ what uplink power range is
recommend for non-gain antennas?_ Is there one range that should cover
the LEOs? If not, how much should I expect the required uplink power
needs to vary across various satellites? Is it different for each band?
I have read that it is always best to never be louder than the beacon
and that's fine. I'm just needing to know where to start off my
hardware choices.
Thanks in advance for any help from you folks with the know-how. I look
forward to a qso with you.
.paul ac0z
_______________________________________________
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
I'm surprised that you have had only one reply. I am not QRV on the
Leos so my advise is not as good as what you might get. My
"understanding" is that one can work most of the Leos with power
<10w. This is IF the stations on the bird also comply by not using
more power than is needed. If a "power war" ensues to try to capture
the satellite then running low power may be less effective to "break in".

But seeing that so many folks run HT's that typically are 5w, I think
you might chose the lowest range as long as your equipment output
matches. You have to consider that you will have no antenna gain
using omni-directional antennas so uplink RF power needs are
affected, accordingly. NOW if some experienced sat op will add their
input on this subject you should have the info you need.

I wonder if the Ramsey preamps allow for "hard" switching. That is
by separate control line that the radio PTT controls. Then You have
no issue with RF power and would run the units with the RF sense
disabled. I should state that "many" (dare I say most) experienced
VHFers that run high power (>100w) use hard-wired switching. I know
of NO eme stations that use RF sense control lines.

PS: when my standard AO-10/13/40 ground station is re-installed I
will have available 5-60w with 16.5 dBc UHF uplink (all-mode).


***********************************************************
73, Ed - KL7UW BP40iq, 6m - 3cm
144-EME: FT-847, mgf-1801, 4x-xp20, 185w
1296-EME: DEMI-Xvtr, 0.30 dBNF, 4.9m dish, 60W
http://www.kl7uw.com AK VHF-Up Group
NA Rep. for DUBUS: ***@hotmail.com
***********************************************************
n***@bellsouth.net
2008-10-19 18:05:32 UTC
Permalink
Paul and all,

I would be curious to hear from anyone currently using verticals with preamps as their primary receive antennas. I have hesitated to respond to your initial post, Paul, because (1) I am very new to the satellites; (2) as a result, my personal experience with antennas involves only the Arrow handheld antenna, the eFactor 0-gain omni antenna, the Elk dual-band log periodic an MFJ mag-mount dual-band vertical for my vehicle, and HT-specific antennas (Pryme AL800, MFJ 1715 and 1717, etc.); and (3) my other knowledge regarding using omni antennas for satellite work is limited to what I have read here and elsewhere on the Internet.

All of that being said, I believe I would opt for something other than a vertical - even with preamps - as my prime base-station antennas for the satellies. I haven't yet built one of the Ramsey preamps, but I intend to as the weather turns cool here in North Georgia and I spend more time inside. I am curious about its ability to improve reception for me with the sFactor, which is an outstanding transmit antenna for reaching the satellites - based on my experiences with it. I also logged more than a dozen contacts involving AO-27, AO-51 and SO-50 using the eFactor with an HT as a handheld antenna. My personal experience suggests that a preamp would help it on the UHF receive side a great deal, although it honestly exceeded my expectations - given the physical size of the UHF part of the antenna.

The N3TL handheld station has worked 46 states, VE1-2-3-4-5-6-8-9, Mexico, Venezuela, Barbados and marimtime mobile stations all on 5 watts' rf out or less. It also has worked 20 states, Ontario, Mexico and Venezuela on .05-watt (50 milliwatts) on the same set of 2 AA Duracell batteries. For the sake of perspective, I made my first-ever satellite contact on June 28th of this year - less than 4 months ago.
Edward Cole
2008-10-19 20:06:30 UTC
Permalink
Very good points, Tim.

Comments on vertical antennas. First define vertical: 1) If you are
referring to a high-gain FM base station antenna, then I would NOT
recommend using one (because the gain compresses the signal pattern
down near the horizon - for better repeater operation at long
range). 2) If you mean a simple 1/4 wavelength ground-plane whip
(like a 19-inch mag-mount attached to a square of sheet steel for the
ground-plane), then (if used with a preamp) it will work quite well
at either 2m or 70cm on Leo's.

Of course you need to use a preamp for the freq. band you desire to
receive. I used a 19-inch mag-mt with P432VGA preamp to collect UHF
telemetry from AO-51 shortly after launch. Also obvious is the need
to provide bypass switching for preamp if you anticipate using the
antenna for transmitting.

The M2 eggbeaters are probably slightly better than (and a whole lot
more $$$) a 19-inch whip as are other more advanced omnis such as:
Lindenblad, and Quadrafillar Helix. But a simple little mag-mt 2m
whip works great (especially with a preamp). For a home-based Leo
station, I think they are fine. For portable (standing in the
parking lot) operation the handheld Arrow is hard to beat.

For hard-core operation using Oscar-0, may I suggest what I am
currently building (tongue-in-cheek):
http://www.kl7uw.com/eme1296.htm

73, Ed - KL7UW
Post by n***@bellsouth.net
Paul and all,
I would be curious to hear from anyone currently using verticals
with preamps as their primary receive antennas. I have hesitated to
respond to your initial post, Paul, because (1) I am very new to the
satellites; (2) as a result, my personal experience with antennas
involves only the Arrow handheld antenna, the eFactor 0-gain omni
antenna, the Elk dual-band log periodic an MFJ mag-mount dual-band
vertical for my vehicle, and HT-specific antennas (Pryme AL800, MFJ
1715 and 1717, etc.); and (3) my other knowledge regarding using
omni antennas for satellite work is limited to what I have read here
and elsewhere on the Internet.
All of that being said, I believe I would opt for something other
than a vertical - even with preamps - as my prime base-station
antennas for the satellies. I haven't yet built one of the Ramsey
preamps, but I intend to as the weather turns cool here in North
Georgia and I spend more time inside. I am curious about its ability
to improve reception for me with the sFactor, which is an
outstanding transmit antenna for reaching the satellites - based on
my experiences with it. I also logged more than a dozen contacts
involving AO-27, AO-51 and SO-50 using the eFactor with an HT as a
handheld antenna. My personal experience suggests that a preamp
would help it on the UHF receive side a great deal, although it
honestly exceeded my expectations - given the physical size of the
UHF part of the antenna.
The N3TL handheld station has worked 46 states, VE1-2-3-4-5-6-8-9,
Mexico, Venezuela, Barbados and marimtime mobile stations all on 5
watts' rf out or less. It also has worked 20 states, Ontario, Mexico
and Venezuela on .05-watt (50 milliwatts) on the same set of 2 AA
Duracell batteries. For the sake of perspective, I made my
first-ever satellite contact on June 28th of this year - less than 4
months ago.
Gordon JC Pearce MM3YEQ
2008-10-20 07:10:32 UTC
Permalink
Post by Edward Cole
But seeing that so many folks run HT's that typically are 5w, I think
you might chose the lowest range as long as your equipment output
matches. You have to consider that you will have no antenna gain
using omni-directional antennas so uplink RF power needs are
affected, accordingly. NOW if some experienced sat op will add their
input on this subject you should have the info you need.
I have a small amount of experience in this ;-)

I've successfully worked about half a dozen contacts (not trying very
hard) with a Trio TH-F7 HT and a homebrew Arrow-type antenna, and a
fairly "approximate" diplexer. The antenna is a 3-element Yagi for 2m
and a 5-element Yagi for 70cm. The HT puts out only 5W on high power,
but it can wake up AO-51, SO-50 and AO-27.

Unfortunately AO-51 seems to be plagued by the same cretins that jam
repeaters with silly noises and bursts of music at certain times. Even
when they're not doing that there's always someone trying to run 2.5kW
into a massive stacked antenna. I've noticed that these are also the
ones that sit there calling "CEEEE KYOOOOOOOOOOOOOOO CEEEEEEEEEEE
KYOOOOOOO CEEEEEEEEEEEE KYOOOOOOOOOOOOOOOOOO <whistle whistle whistle>
CEEEEEEEEEE KYOOOOOOOOOO CEEEEEEEEEEE KYOOOOOOOOOOOOO CEEEEEEEEEEEEE
KYUUUUUUU" for nearly the whole damn pass without pausing for breath.

Gordon
Dave Guimont
2008-10-20 18:25:23 UTC
Permalink
Post by Gordon JC Pearce MM3YEQ
Unfortunately AO-51 seems to be plagued by the same cretins that jam
repeaters with silly noises and bursts of music at certain times. Even
when they're not doing that there's always someone trying to run 2.5kW
into a massive stacked antenna. I've noticed that these are also the
ones that sit there calling "CEEEE KYOOOOOOOOOOOOOOO CEEEEEEEEEEE
KYOOOOOOO CEEEEEEEEEEEE KYOOOOOOOOOOOOOOOOOO <whistle whistle whistle>
CEEEEEEEEEE KYOOOOOOOOOO CEEEEEEEEEEE KYOOOOOOOOOOOOO CEEEEEEEEEEEEE
KYUUUUUUU" for nearly the whole damn pass without pausing for breath.
This fact was anticipated by interested AMSAT members many years
prior to the launch of AO51, with respect to 2-user FM voice. It
was voiced at several conventions that I attended, and some of us
were told by some of the "powers that were" that is was "none of our
business"!! At that time some of us had only one vote each!!




73, Dave, WB6LLO
***@san.rr.com

Disagree: I learn....

Pulling for P3E...
Ben Jackson
2008-10-21 18:01:09 UTC
Permalink
Post by Gordon JC Pearce MM3YEQ
Unfortunately AO-51 seems to be plagued by the same cretins that jam
repeaters with silly noises and bursts of music at certain times. Even
when they're not doing that there's always someone trying to run 2.5kW
into a massive stacked antenna. I've noticed that these are also the
ones that sit there calling "CEEEE KYOOOOOOOOOOOOOOO CEEEEEEEEEEE
KYOOOOOOO CEEEEEEEEEEEE KYOOOOOOOOOOOOOOOOOO <whistle whistle whistle>
CEEEEEEEEEE KYOOOOOOOOOO CEEEEEEEEEEE KYOOOOOOOOOOOOO CEEEEEEEEEEEEE
KYUUUUUUU" for nearly the whole damn pass without pausing for breath.
While this is an issue, it is often overblown (at least in the US). I
think the solution involves education and outreach. When someone like
this is one of the Easy Sats, I grin an bear it and then look them up on
QRZ for an e-mail address. I send them a Hi-Ho, tell them they made it
in, and point them in the right direction for proper operation. If
someone is a repeat offender, sadly the only way to deal with them is
try not to talk to them and hope they get bored.

<shameless_plug>
I addressed most of these concerns in my "The Courteous Ham's Guide to
AO-51" paper that I wrote in March. You can check it out at:
http://www.innismir.net/article/26
</shameless_plug>

As a community, the first step for fixing these problems on satellites
should be outreach and education. More people getting into satellites is
a good thing and we should be encouraging it. If people aren't
"behaving" we should be the first people to offer a helping hand.


- --
Ben Jackson - N1WBV - New Bedford, MA
bbj <at> innismir.net - http://www.innismir.net/
Tony Langdon
2008-10-21 20:12:09 UTC
Permalink
Post by Ben Jackson
While this is an issue, it is often overblown (at least in the US). I
think the solution involves education and outreach. When someone like
this is one of the Easy Sats, I grin an bear it and then look them up on
QRZ for an e-mail address. I send them a Hi-Ho, tell them they made it
I agree. Many newcomers don't know how to operate on sats, and this
is often compounded by poor receive performance on many beginners'
stations. On many occasions, if an offending station was within
simplex range, I'd call them aside after the pass, and have a bit of
a chat. If there was another pass to follow, I'd invite them to have
another go, focusing on receiving the downlink, and if they do hear
the bird, giving a quick call and try their luck. In the downtime
between or after passes, we'd talk about things like improving
downlink reception. One year, while holidaying in Queensland, I had
a whole bunch of locals using UO-14 with portable gear, after talking
them through the process on the local repeater before the passes.
:) If people have a HT, I will suggest they take it outside during a
pass and have a listen, if they don't have any suitable antennas already setup.

Almost everyone I have spoken to has gone on to make a successful
satellite contact, after this bit of Elmering.
Post by Ben Jackson
in, and point them in the right direction for proper operation. If
someone is a repeat offender, sadly the only way to deal with them is
try not to talk to them and hope they get bored.
That's about all you can do...
Post by Ben Jackson
<shameless_plug>
I addressed most of these concerns in my "The Courteous Ham's Guide to
http://www.innismir.net/article/26
</shameless_plug>
Cool. I wrote a similar piece around 8 years ago called
"satiquette", which addressed these issues on FM birds. At the
time, SO-35 was active, and that was hugely popular down here. It
was a lot of fun. :) I also wrote some articles on using SO-35's
parrot mode, which took a lot of skill to get any useable
throughput. The parrot (for those who don't know or recall) was
basically a simplex store and forward repeater that worked in the
following cycles: <single tone> 10 second uplink slot (satellite
receiving) <double tones> 10 second downlink slot (satellite
transmitting). As one could imagine, this had _massive_ hidden
station issues, but if you did it right, you could get a QSO. Just
enough time to get a callsign and RST, with time for one or two
others to do the same in the slot. :)
Post by Ben Jackson
As a community, the first step for fixing these problems on satellites
should be outreach and education. More people getting into satellites is
a good thing and we should be encouraging it. If people aren't
"behaving" we should be the first people to offer a helping hand.
Agree. The majority of "anti-social" behaviour is actually
ignorance, and education goes a long way to making things work smoothly. :)

73 de VK3JED
http://vkradio.com

corner5
2008-10-19 20:22:07 UTC
Permalink
Thanks for replys (Re: beginner question re: uplink power)

In response to two points contained in replys from helpful others...
Ed - KL7UW: I wonder if the Ramsey preamps allow for "hard" switching. That is
by separate control line that the radio PTT controls. Then You have
no issue with RF power and would run the units with the RF sense
disabled. I should state that "many" (dare I say most) experienced
VHFers that run high power (>100w) use hard-wired switching. I know
of NO eme stations that use RF sense control lines.

A: Ed, yes this is a good suggestion. In fact these preamps are very simple units. No, they do not have any switching that would
allow for external PPT communication from the TS2000 (0-***@2m, 0-***@70cm). That said, I certainly could add my own mast mount external relay
to do the switching. I also could simply install a DPDT or TPDT switch at the shack end and manually do the switching. This last
approach could lead to smoking the preamp the one time I forget to toggle it out of line. So, in the end I chose to
go with the RF sense remote switch. I hope the need to contain my uplink RF withing a chosen range (0-10 or
10-30 or 30-100 watts) will not be too limiting.
Tim - N3TL: I would be curious to hear from anyone currently using verticals with preamps as their primary receive antennas.
A: Tim, I think technically you would not call my antennas vertical, but here is what I will start using:
I have now completed the 2m / 70cm pair of double moxon (co-phased) fixed omnis. Each antenna has two moxons that
are 90 deg to each other. I used the plans as published in
QST, August 2001, author = L.B. Cebik. I chose these antennas do to wishing to avoid the expense and tracking logistics of
a beam (for my first setup). I suspect I will go to this upgrade later as I learn more. Some prefer the more
conventional turn-style design, Lindenblad, Quadrafillar Helix but I thought I would try this out and see.
Roger,WA1KAT: I think I would contact Ramsey and see what the resistor selection
limitations are, unless you have a schematic and can determine it from the
design.

A: In fact I already have both the schematic as well as the resistor values that achieve the specific power windows.
I verified with Ramsey that if I wanted I could replace the resistor with a pot for a full range. Unfortunately
this does not really address the fact that I will still be restricted to a given range (although with the pot I
would have more flexibility as to choosing my range). Also a more wacky thought I had was to have the resistors
(or pots) located in the shack and toggle them as needed.
Roger,WA1KAT: Hard wiring, as has been suggested, is your safest choice. As the switch has
the relay in it, maybe Ramsey can tell you where to tap in to directly
switch the sensor.

A: This is a very interesting approach. If I understand your idea here, you suggest to use the relay that is
on the RF switch board and toggle this relay with a PPT signal from the TS2000 (and not make use of the RF sense at all. Yes?
I do not know about the details of using the PPT signal in this way. I guess I need to hope that the PPT signal
is compatible with the relay (voltage). And then if I need to abandon the RF switch all together, are there suggestions
as to what is a good (not too expensive) remote relay design?

thanks all!
.paul AC0z
Edward Cole
2008-10-19 20:30:34 UTC
Permalink
Post by corner5
Thanks for replys (Re: beginner question re: uplink power)
===snip===
A: This is a very interesting approach. If I understand your idea
here, you suggest to use the relay that is
on the RF switch board and toggle this relay with a PPT signal from
the TS2000 (and not make use of the RF sense at all. Yes?
I do not know about the details of using the PPT signal in this way.
I guess I need to hope that the PPT signal
is compatible with the relay (voltage). And then if I need to
abandon the RF switch all together, are there suggestions
as to what is a good (not too expensive) remote relay design?
Most radios have an aux. TX key line. This will either key the line
to ground (like PTT does), or will provide (usually +12) voltage in
transmit to drive a relay.
Most likely the relays in the Ramsey unit are 12volt relays.

In case #1, you lift the ground lead of the relay and attach that to
your control line from the radio.
In case #2, you lift the +12v lead to the relay (from the RF sense
ckt) and attach that to your control line.
You probably only need one wire as the preamp dc power wiring will
provide the other wire which ever case# applies. If the preamp is
powered over the RF coax line, the radio may not supply sufficient
current to drive the unit (check this out in the radio manual and
Ramsey specs).

I would also disconnect the relay from the RF sense ckt in any case
so that it does not cause any false keying issues.

Simple! Enjoy!

73 - Ed
Michael Tondee
2008-10-19 22:18:01 UTC
Permalink
Paul,
If i remember correctly there was gent on this board awhile back that
reported some issues with the RF switching of Ramsey preamps. I believe the
problem had something to do with the switching cutting in and out while
using SSB. I can't remember the exact issue. though. Still you may want to
take this into consideration when making the decision whether to go with
hard switching or not.
73,
Michael,W4HIJ
----- Original Message -----
From: "corner5" <***@comcast.net>
To: <amsat-***@amsat.org>; <***@comcast.net>
Sent: Sunday, October 19, 2008 4:22 PM
Subject: [amsat-bb] Re: beginner question re: uplink power
Post by corner5
Thanks for replys (Re: beginner question re: uplink power)
In response to two points contained in replys from helpful others...
Ed - KL7UW: I wonder if the Ramsey preamps allow for "hard" switching.
That is
by separate control line that the radio PTT controls. Then You have
no issue with RF power and would run the units with the RF sense
disabled. I should state that "many" (dare I say most) experienced
VHFers that run high power (>100w) use hard-wired switching. I know
of NO eme stations that use RF sense control lines.
A: Ed, yes this is a good suggestion. In fact these preamps are very
simple units. No, they do not have any switching that would
relay
to do the switching. I also could simply install a DPDT or TPDT switch at
the shack end and manually do the switching. This last
approach could lead to smoking the preamp the one time I forget to toggle
it out of line. So, in the end I chose to
go with the RF sense remote switch. I hope the need to contain my uplink
RF withing a chosen range (0-10 or
10-30 or 30-100 watts) will not be too limiting.
Roger,WA1KAT: Hard wiring, as has been suggested, is your safest choice.
As the switch has
the relay in it, maybe Ramsey can tell you where to tap in to directly
switch the sensor.
A: This is a very interesting approach. If I understand your idea here,
you suggest to use the relay that is
on the RF switch board and toggle this relay with a PPT signal from the
TS2000 (and not make use of the RF sense at all. Yes?
I do not know about the details of using the PPT signal in this way. I
guess I need to hope that the PPT signal
is compatible with the relay (voltage). And then if I need to abandon the
RF switch all together, are there suggestions
as to what is a good (not too expensive) remote relay design?
thanks all!
.paul AC0z
Continue reading on narkive:
Loading...