wrote:

dxAce wrote:
Correct me if I'm wrong... but would it not be better to run some
pre-amplification ahead of the splitter rather than try to make up
something that has already disappeared? Much the same in say VHF work
where it is better to run a receive pre-amp right at the antenna versus
running it at the receiver end of the coax?

I'd never consider using a passive splitter here, and I rarely if ever
engage the
pre-amps on the receivers... no need.

dxAce
Michigan
USA
------------------------------
The results might surprise you.

The results of what? Using a passive splitter?


When I received my zfsc-2-1 I expected the addional ~3.5dB loss to be
an
issue. But after much testing I found that it didn't make that much
difference.
For the most part any signal I could receive without the addtional loss
was
still present with the loss. I used a HP step atenuator to check this
before going to the trouble of mounting the zfsc.

I really expected to need a good low noise, high intercept, preamp
before
the splitter. If you have a "good enough" antenna the additional loss
is of slight concern.

But it is still a loss, is it not?

Since I have all of my antennas, receivers, RF filters on a patch
panel,
it allows me to easily move the splitter out of line. I use BNC
connectors
because I was given a "boat load" of them and find them easier and
faster to move then PL/SO-259 connectors.

A friend wanted a similar setup and I gave him enough bulkhead mount
"F" femalefemale to allow him to bring all of his antenas and both
receivers to a panel. He found an "old" TV spliter that works very well
to below the MW/BCB band. I bought a bag of over 500 for $1 at the
local Goodwill store.

Another advantage of a RF patch panel is I can connect my Pro2004 IF
out to my R2000 so I can listen to SSB VHF/UFF comms.

I do have to be very carefull to insure that I don't connect my ham
gear to
my receiver inputs. At them moment I have them feeding different RF
patch
panels and simply don't ever connect my ham gear to a receive antenna.
I am considering switching all of my receive RF connectors to "F", at
least
at the patch panel. I have thought of using TNC but they are expensive
and are easier to crossthread then "F".

You've made no pertinent point.

dxAce
Michigan
USA

dxAce wrote:
dxAce Apr 17, 3:11 pm show options
Newsgroups: rec.radio.shortwave
From: dxAce - Find messages by this author
Date: Sun, 17 Apr 2005 18:11:26 -0400
Local: Sun,Apr 17 2005 3:11 pm
Subject: splitter ?
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Yes, the calibration may indeed be off with various manufacturers,
however all things being equal it should be very easy to determine
various antenna changes with a 'particular' receiver.

Damn simple.

dxAce
Michigan
USA
---------------------------
Sadly very few radios have S-meters that behave in a "correct" way.
I have a HP calibrated step attenuator, with .5dB steps. Zin 50Ohm
Zout 50 Ohm. When checked at the electronics lab (at UK) the
error was less then .07dB worst case. I have a simple crystal osc that
is very temp stable. Zout 50 Ohms at .1V. Measured to be 0.10V.

I have had chance to check quite a few receivers. From the famous
R390, to one of the Lowe 150s. I would have to dig out my notes, if
I even still have them, and the R390 was the ony one that tracked
6dB/1S unit.

This url has better data then I can dig out out the moment:
http://www.ac6v.com/sunit.htm

Unless you know, that is have measured, your S-meter, it is only
a rough indication.

You can clearly use your S meter to compare one antenna to another,
but I would be very hesitant to say that "antenna 1 is S2 and antenna
2 is S6, therefore antenna 2 has 24dB more gain then antenna 1."
Based on the assumption that 1 S unit equals 6 dB.
S6-S2=4 S-units, 4 X6dB = 24dB
(Math shown for those new to the hobby)

Now if you have a calibrated step attenuator you could show that:
Ant 1 gives S2
Ant 2 requires 20dB of attenuation to give a reading of S2.
Ant 2 has about 20dB more gain then Ant 1.

I bought my Hp attenuator at a surplus store for $5.
I bought 2 fox industries 50P-077 +12V BCD attenuators
that have a measured error of less then .01dB for $1each!
Coupled with some Pasternak PE7101 coaxial relays I hope
to be able to some "meaningfull" antenna experiments this
summer and next winter.

There is a vacant lot caty corner behind us and I have permission
from the lot owner, and both my rear and next door neigbors to run
an temp antenna to and across that lot. I will be able to get about
300' of wire up in a straight line. I intend to see just how length
effect
signal strength.

Next fall a frined is going to let me spend a few weekends on his
fields to check even longer wires.

Terry

wrote:

dxAce wrote:
dxAce Apr 17, 3:11 pm show options
Newsgroups: rec.radio.shortwave
From: dxAce - Find messages by this author
Date: Sun, 17 Apr 2005 18:11:26 -0400
Local: Sun,Apr 17 2005 3:11 pm
Subject: splitter ?
Reply | Reply to Author | Forward | Print | Individual Message | Show
original | Report Abuse

- Hide quoted text -
- Show quoted text -
Yes, the calibration may indeed be off with various manufacturers,
however all things being equal it should be very easy to determine
various antenna changes with a 'particular' receiver.

Damn simple.

dxAce
Michigan
USA
---------------------------
Sadly very few radios have S-meters that behave in a "correct" way.
I have a HP calibrated step attenuator, with .5dB steps. Zin 50Ohm
Zout 50 Ohm. When checked at the electronics lab (at UK) the
error was less then .07dB worst case. I have a simple crystal osc that
is very temp stable. Zout 50 Ohms at .1V. Measured to be 0.10V.

I have had chance to check quite a few receivers. From the famous
R390, to one of the Lowe 150s. I would have to dig out my notes, if
I even still have them, and the R390 was the ony one that tracked
6dB/1S unit.

This url has better data then I can dig out out the moment:
http://www.ac6v.com/sunit.htm

Unless you know, that is have measured, your S-meter, it is only
a rough indication.

Yes, of course. (No ****, Sherlock)

You can clearly use your S meter to compare one antenna to another,
but I would be very hesitant to say that "antenna 1 is S2 and antenna
2 is S6, therefore antenna 2 has 24dB more gain then antenna 1."

No one was trying to say that.

Based on the assumption that 1 S unit equals 6 dB.
S6-S2=4 S-units, 4 X6dB = 24dB
(Math shown for those new to the hobby)

Now if you have a calibrated step attenuator you could show that:
Ant 1 gives S2
Ant 2 requires 20dB of attenuation to give a reading of S2.
Ant 2 has about 20dB more gain then Ant 1.

I bought my Hp attenuator at a surplus store for $5.
I bought 2 fox industries 50P-077 +12V BCD attenuators
that have a measured error of less then .01dB for $1each!
Coupled with some Pasternak PE7101 coaxial relays I hope
to be able to some "meaningfull" antenna experiments this
summer and next winter.

There is a vacant lot caty corner behind us and I have permission
from the lot owner, and both my rear and next door neigbors to run
an temp antenna to and across that lot. I will be able to get about
300' of wire up in a straight line. I intend to see just how length
effect
signal strength.

Next fall a frined is going to let me spend a few weekends on his
fields to check even longer wires.

Yes.. but you wasted most of the space above to say nothing.

Boggling to say the least...

I'm more and more amazed here everyday.

Continue to tote.

dxAce
Michigan
USA

sorry Mike, email on the way...
Drifter...

BNCs are certainly the way to go as opposed to PL-259

If you keep your eyes open, you can get real RF patch bays. I don't
know the name of the connector, but they are really patches, i.e. no
threads. About the only way to buy these RF patch bays is with the
patches at the same time. There seem to be two similar designs, but the
dimensions are not quite the same. I ohmed out all the connectors
before buying any of the patch cables. The whole deal about about $30
to $40 a few years ago. Mine had the stickers on from a radar company
(Whistler), so I'm pretty sure it was 50 ohm. I guess there is a risk
you might get a 75 ohm video patch bay.

Unless the pre-amp is as clean as your radio, I'd take the loss in the
splitter and make it up in the AGC. I wouldn't want to risk intermod in
the amp degrading the reception of the signal.

Signal strength and quality of the signal are not always related. You
can experiment by taking a strong signal and pad it down with an
antennuator to the level of some weak signal. The padded down strong
signal tends to sound cleaner. I think this is because the pad also
reduced the level of the background noise at the same time, while a
weak signal has a lower signal to noise ratio "naturally." I hope that
makes sense.

- Hide quoted text -
- Show quoted text -
************************

thanks to one and all for some great info.
i need to study on this. i found an old article
in the july/04, NASWA Journal. get my facts together
here, and move to there. would be fun to build when
i find the time. thanks again...
Drifter...

wrote:

BNCs are certainly the way to go as opposed to PL-259

If you keep your eyes open, you can get real RF patch bays. I don't
know the name of the connector, but they are really patches, i.e. no
threads. About the only way to buy these RF patch bays is with the
patches at the same time. There seem to be two similar designs, but the
dimensions are not quite the same. I ohmed out all the connectors
before buying any of the patch cables. The whole deal about about $30
to $40 a few years ago. Mine had the stickers on from a radar company
(Whistler), so I'm pretty sure it was 50 ohm. I guess there is a risk
you might get a 75 ohm video patch bay.

Unless the pre-amp is as clean as your radio, I'd take the loss in the
splitter and make it up in the AGC. I wouldn't want to risk intermod in
the amp degrading the reception of the signal.

Signal strength and quality of the signal are not always related. You
can experiment by taking a strong signal and pad it down with an
antennuator to the level of some weak signal. The padded down strong
signal tends to sound cleaner. I think this is because the pad also
reduced the level of the background noise at the same time, while a
weak signal has a lower signal to noise ratio "naturally." I hope that
makes sense.


http://www.switchcraft.com/products/vpp.html &
http://www.switchcraft.com/products/561.html are examples of video patch
bays and plugs that work for HF receivers as well. They are used for
manual routing of video in some studios and transmitter sites. Western
Electric used to use them on their coaxial long lines that fed video
cross country before TV satellites were available. If you're old enough
to remember the nationwide live video feed after President Kennedy was
assassinated, the techs and engineers at ATT patched together the first
nationwide feed by connecting the different network's feeds together to
provide all network stations with live video and did the same with the
audio feeds.


--
Former professional electron wrangler.

Michael A. Terrell
Central Florida

"dxAce" wrote in message
...


"Charles W. Hinkle" wrote:

I have used Mini Circut Labs ZFSC-2-1 and a 2 port passive Stridsberg.
I
obtained the MCL's at hamfests for $10 and the Stridsberg new Presently
I
am using a MCL PSC-3-1 to feed 3 receivers. I also got this at a
hamfest.
My receivers make up the nearly 5 db loss.

How do they make up the loss? Just curious.

dxAce
Michigan
USA

Same question here.

Dale W4OP

On Mon, 18 Apr 2005 02:43:05 GMT, "Michael A. Terrell"
wrote:


http://www.switchcraft.com/products/vpp.html &
http://www.switchcraft.com/products/561.html are examples of video patch
bays and plugs that work for HF receivers as well. They are used for
manual routing of video in some studios and transmitter sites. Western
Electric used to use them on their coaxial long lines that fed video
cross country before TV satellites were available. If you're old enough
to remember the nationwide live video feed after President Kennedy was
assassinated, the techs and engineers at ATT patched together the first
nationwide feed by connecting the different network's feeds together to
provide all network stations with live video and did the same with the
audio feeds.
75 Ohms, if that matters.

If you're going to use RG-59/U, you might as well just use
ubiquitous and cheap F-Connectors and A/B/C switches.

David wrote:

On Mon, 18 Apr 2005 02:43:05 GMT, "Michael A. Terrell"
wrote:

http://www.switchcraft.com/products/vpp.html &
http://www.switchcraft.com/products/561.html are examples of video patch
bays and plugs that work for HF receivers as well. They are used for
manual routing of video in some studios and transmitter sites. Western
Electric used to use them on their coaxial long lines that fed video
cross country before TV satellites were available. If you're old enough
to remember the nationwide live video feed after President Kennedy was
assassinated, the techs and engineers at ATT patched together the first
nationwide feed by connecting the different network's feeds together to
provide all network stations with live video and did the same with the
audio feeds.
75 Ohms, if that matters.

If you're going to use RG-59/U, you might as well just use
ubiquitous and cheap F-Connectors and A/B/C switches.


If you want to use 75 ohm cables its your choice. The patch bays are
BNC on both halves so you can use 50 or 75 ohm cables with them. These
patch bays show up used and surplus along with the plugs. I've used
them at several TV stations, a mobile production van I built and in the
telemetry package we shipped to Italy. They are a lot better quality
than "F" fittings and CATV switches. I used to run insertion loss and
other tests on samples for United Video Cablevision and there was more
junk submitted than quality parts. Even the better quality switches
only lasted a year or so when we used them to reroute video feeds in the
L.O. studio.

--
Former professional electron wrangler.

Michael A. Terrell
Central Florida