Author Topic: Anzac H-125 hybrid junction  (Read 8360 times)

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Offline AF6LJ

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Re: Anzac H-125 hybrid junction
« Reply #25 on: February 24, 2017, 12:57:04 pm »
That should work, however all three ports need to be terminated with something.
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Offline bsalaiTopic starter

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Re: Anzac H-125 hybrid junction
« Reply #26 on: February 26, 2017, 12:44:22 am »
Here's what I did. I terminated the common port with 50 ohms. I fed a signal into one of the other ports and connected it to a 50 ohm input of my scope. I measured the output of the signal generator with the same scope, but only connected to the scope.
The signal generator output was 300mV, the output of the port that the signal generator wasn't connected to was 5mV. I tried calculating the power ratio, using P=E squared/50  and got 90 db. That seems unlikely, where did I go wrong?


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Offline T3sl4co1l

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Re: Anzac H-125 hybrid junction
« Reply #27 on: February 26, 2017, 01:22:36 am »
log10(300 / 5) * 20 = 35.6 dB.

The 20 gets decibels from volts.  If you use power, it's 10.  Multiplication outside a log is exponentiation within the log, and power goes as volts squared, so this is equivalent.

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Offline bsalaiTopic starter

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Re: Anzac H-125 hybrid junction
« Reply #28 on: February 26, 2017, 01:29:27 am »
Got it, thanks. That is a reasonable number I would think.
I tried a range of frequencies, the isolation starts to drop above 50MHz. It stays pretty constant down to 700kHz.


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Offline bsalaiTopic starter

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Re: Anzac H-125 hybrid junction
« Reply #29 on: February 26, 2017, 02:05:55 am »
I'm wondering what I could use it for. The isolation isn't quite enough to connect a transmitter and receiver to one antenna. Maybe a QRP transmitter?


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Offline AF6LJ

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Re: Anzac H-125 hybrid junction
« Reply #30 on: February 26, 2017, 02:08:05 am »
That is interesting, a lot of loss.
Would be interesting to feed the generator into the common port.
Connect the scope to one port and terminate the other.
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Offline bsalaiTopic starter

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Re: Anzac H-125 hybrid junction
« Reply #31 on: February 26, 2017, 02:09:35 am »
I'll try that in the morning. I could try it tonight but then I would be single in the morning!


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Offline bsalaiTopic starter

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Re: Anzac H-125 hybrid junction
« Reply #32 on: February 26, 2017, 02:17:13 am »
I tried it. 120mV out. Both ports are the same.


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Offline edpalmer42

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Re: Anzac H-125 hybrid junction
« Reply #33 on: February 26, 2017, 03:28:36 am »
I'm wondering what I could use it for. The isolation isn't quite enough to connect a transmitter and receiver to one antenna. Maybe a QRP transmitter?


I've been following this thread with some interest.  I've never used a hybrid junction and wanted to see what the result was.  When I looked around, I found this one:  http://www.ebay.com/itm/321364367967 .  I'm still not sure what you'd use it for, but if yours works the same, a dual trace scope hooked up to the two outputs should show the phase shift.

Ed

 

Offline bsalaiTopic starter

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Re: Anzac H-125 hybrid junction
« Reply #34 on: February 26, 2017, 09:05:07 am »
I have done that, but without terminating the ports and the phase difference was no more than a few degrees between the output ports. I'm going to try it again with terminators on the ports ahead of the high impedance scope inputs.


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Offline bsalaiTopic starter

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Re: Anzac H-125 hybrid junction
« Reply #35 on: March 20, 2017, 10:35:11 pm »
I finally got the terminators that I need put together and have made some measurements that just might be valid. Connecting the signal generator to what I will call the input port, terminating one of the outputs and measuring the signal at the other using a 50 ohm termination at the scope input gives approximately a three dB loss from just below 1 MHz to about 60 MHz. The phase changes from about 0° at the low-end to about 180° at 60 MHz.

The isolation between the output ports is about 40 dB from below 1 to 60 MHz and decreases above that.
Now the question is, what can I make with it.
Brad W2EK


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Offline AF6LJ

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Re: Anzac H-125 hybrid junction
« Reply #36 on: March 20, 2017, 11:05:08 pm »
Very cool, I wonder what the phase change is at say 20, 30, and 45 MHZ...
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Offline edpalmer42

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Re: Anzac H-125 hybrid junction
« Reply #37 on: March 20, 2017, 11:20:54 pm »
Does the phase shift continuously with frequency or is there a frequency range where the phase shift is constant, maybe at 90 degrees?  If so, I suspect that range would specify the operating range of the unit.

As for what you can do with it, well   :-//

Ed
 

Offline bsalaiTopic starter

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Re: Anzac H-125 hybrid junction
« Reply #38 on: March 21, 2017, 02:14:50 am »
I will get some proper data but I think the phase shift was continuous with frequency. I'm away for a week but will do this when I get back.


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Offline AF6LJ

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Re: Anzac H-125 hybrid junction
« Reply #39 on: March 21, 2017, 03:40:41 am »
I will get some proper data but I think the phase shift was continuous with frequency. I'm away for a week but will do this when I get back.


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Sounds good and I would expect it to be a fairly constant change.
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