Can anyone tell me how to build a broadband hybrid combiner for 2
shortwave loop receiving antennas?
I need 45,-45 degrees of phase on the 2 loops from 1 to 30 mhz? I will
be mounting the combiner right at the antenna after the preamps.

Bindy

In article . com, "Bindy"
wrote:

Can anyone tell me how to build a broadband hybrid combiner for 2
shortwave loop receiving antennas?
I need 45,-45 degrees of phase on the 2 loops from 1 to 30 mhz? I will
be mounting the combiner right at the antenna after the preamps.

Bindy

Hello, and since the relative phase difference between the two loops is 90
degress could you not use a quadrature splitter/combiner? Mini-Circuits
and other vendors offer broadband hybrids. While DIY passive, narrow band
hybrids can be easily fashioned out of coax or lumped components, a
broadband device is more challenging.

BTW, you are asking for a device that can operate over a 30:1 frequency
ratio. I would relax that requiement if possible to 15:1 (2 to 30 MHz) or
less for a commercially-available hybrid. Also since you will be using
the combiner for receive only, RF power handling capability of the hybrid
should not be an issue. Sincerely,

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337

Bindy:

You may find the following link of interest:

http://www.w8ji.com/combiner_and_splitters.htm

Regards,
John Smith

"Bindy" wrote in message
ups.com...
Can anyone tell me how to build a broadband hybrid combiner for 2
shortwave loop receiving antennas?
I need 45,-45 degrees of phase on the 2 loops from 1 to 30 mhz? I will
be mounting the combiner right at the antenna after the preamps.

Bindy

In article , "John Smith"
wrote:

Bindy:

You may find the following link of interest:

http://www.w8ji.com/combiner_and_splitters.htm

Regards,
John Smith

Hello, John, and that link does not cover 0-90 degree (quadrature) hybrids
which I'm guessing is what Bindy is after. A commercially-available
broadband quadrature combiner/splitter is usually implemented using a 0-0
or 0-180 hybrid to which an all-pass network is added to achieve the
desired phase difference out the output ports of the hybrid. Getting
these devices to behave properly over a broad frequency range is somewhat
of a black art and vendors such as Mini-Circuits and Merrimac keep these
techniques to themselves. Sincerely, and 73s from N4GG0,

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337

Hello, John, and that link does not cover 0-90 degree (quadrature) hybrids
which I'm guessing is what Bindy is after. A commercially-available
broadband quadrature combiner/splitter is usually implemented using a 0-0
or 0-180 hybrid to which an all-pass network is added to achieve the
desired phase difference out the output ports of the hybrid. Getting
these devices to behave properly over a broad frequency range is somewhat
of a black art and vendors such as Mini-Circuits and Merrimac keep these
techniques to themselves. Sincerely, and 73s from N4GG0,

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337

Hello both Johns. and one Bindy.

Here's how one person did it, and published in QEX November 1982.

"How to design wide-band RF Quadrature Network".

G.W. Horn, I4MK Bologna, Italy

It's not elementary, but he (and VE5FP/VK2BOX) made successful ones that
covered 3-30 MHz nicely. Horn gives the equations that must be satisfied to
accomplish the task.

If you have difficulty retrieving the article, the call book shows the call
sign still active. Might drop him a line.

W4ZCB

Bindy wrote:
Can anyone tell me how to build a broadband hybrid combiner for 2
shortwave loop receiving antennas?
I need 45,-45 degrees of phase on the 2 loops from 1 to 30 mhz? I will
be mounting the combiner right at the antenna after the preamps.

Bindy

Thanks for all the suggestions. I pressumed it was possible. I see many
commercial antenna companies like TCI and R&S use hybrids with their
shortwave loops. I just pressumed that it was possible using small
ferrite cores. I cant find anything on google, theres d many references
to microwave hybrids.

Other phase angles might be possible, however 45 degrees ensures that
the loops when phased at right angles behave as a true omni
directional antenna from 1 to 30mhz. Which is the main reason i want to
pursue this option. I am using a MFJ 1026 noise canceller however its a
nuisance and unreliable when wanting consistent and repeatable
performance. It also cant rotate phase for the full 360 degrees.

So a fixed 45 degree hybrid would be ideal..

The search goes on

Thanks
Bindy

Dear "Bindy"

I have blocked so many for inappropriate messages that I might have
missed the point of this sequence. However, it appears from your last
message that your goal is to use a loop antenna or loop antennas to effect
an omnidirectional pattern from 1 to 30 MHz. "True" omnidirectional
antennas do not stay that way when above ground.

If what you are wishing to accomplish is a pattern that is independent
of azimuth using a loop antenna, then a much more simple solution exists -
at least over much of the desired frequency span. A (small) loop mounted
well above ground and oriented horizontally will do the trick. For most HF
receiving purposes, well above ground might indicate a height of between 0.3
and 2.5 WL. Mounting at 30 meters will do nicely from 3 MHz to 25 MHz.
Above 25 MHz there is not much to listen to. Below 3 MHz the pattern favors
nearby stations.

Again, I am not clear about the actual problem to be solved. It is not
clear if this is an amateur application.

73, Mac N8TT
--
J. Mc Laughlin; Michigan U.S.A.
Home:
"Bindy" wrote in message
oups.com...

Bindy wrote:
Can anyone tell me how to build a broadband hybrid combiner for 2
shortwave loop receiving antennas?
I need 45,-45 degrees of phase on the 2 loops from 1 to 30 mhz? I will
be mounting the combiner right at the antenna after the preamps.

Bindy



Thanks for all the suggestions. I pressumed it was possible. I see many
commercial antenna companies like TCI and R&S use hybrids with their
shortwave loops. I just pressumed that it was possible using small
ferrite cores. I cant find anything on google, theres d many references
to microwave hybrids.

Other phase angles might be possible, however 45 degrees ensures that
the loops when phased at right angles behave as a true omni
directional antenna from 1 to 30mhz. Which is the main reason i want to
pursue this option. I am using a MFJ 1026 noise canceller however its a
nuisance and unreliable when wanting consistent and repeatable
performance. It also cant rotate phase for the full 360 degrees.

So a fixed 45 degree hybrid would be ideal..

The search goes on

Thanks
Bindy

J. Mc Laughlin wrote:
Dear "Bindy"

I have blocked so many for inappropriate messages that I might have
missed the point of this sequence. However, it appears from your last
message that your goal is to use a loop antenna or loop antennas to effect
an omnidirectional pattern from 1 to 30 MHz. "True" omnidirectional
antennas do not stay that way when above ground.

If what you are wishing to accomplish is a pattern that is independent
of azimuth using a loop antenna, then a much more simple solution exists -
at least over much of the desired frequency span. A (small) loop mounted
well above ground and oriented horizontally will do the trick. For most HF
receiving purposes, well above ground might indicate a height of between 0.3
and 2.5 WL. Mounting at 30 meters will do nicely from 3 MHz to 25 MHz.
Above 25 MHz there is not much to listen to. Below 3 MHz the pattern favors
nearby stations.

Again, I am not clear about the actual problem to be solved. It is not
clear if this is an amateur application.

73, Mac N8TT
--
J. Mc Laughlin; Michigan U.S.A.
Home:
"Bindy" wrote in message
oups.com...

Bindy wrote:
Can anyone tell me how to build a broadband hybrid combiner for 2
shortwave loop receiving antennas?
I need 45,-45 degrees of phase on the 2 loops from 1 to 30 mhz? I will
be mounting the combiner right at the antenna after the preamps.

Bindy



Thanks for all the suggestions. I pressumed it was possible. I see many
commercial antenna companies like TCI and R&S use hybrids with their
shortwave loops. I just pressumed that it was possible using small
ferrite cores. I cant find anything on google, theres d many references
to microwave hybrids.

Other phase angles might be possible, however 45 degrees ensures that
the loops when phased at right angles behave as a true omni
directional antenna from 1 to 30mhz. Which is the main reason i want to
pursue this option. I am using a MFJ 1026 noise canceller however its a
nuisance and unreliable when wanting consistent and repeatable
performance. It also cant rotate phase for the full 360 degrees.

So a fixed 45 degree hybrid would be ideal..

The search goes on

Thanks
Bindy


Hi Mac

I will be mounting my 2 magnetic loops about 2 meters or 6ft above the
ground. However the loop i am using has very sharp nulls. I believe a
45 degree phase angle will make the pattern totally omni directional.
I could run 2 cables, however hybrid would be simpler.
It seems designing a 45 degree is a tough technical challenge.

Bindy