3 dB HYBRID COUPLER/ISOLATOR FOR ANTENNA SPLITTING 100 KHz -10 MHz

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ON5HB
Posts: 140
Joined: Sat Dec 29, 2018 1:07 pm

Re: 3 dB HYBRID COUPLER/ISOLATOR FOR ANTENNA SPLITTING 100 KHz -10 MHz

Post by ON5HB » Mon Apr 22, 2019 8:58 pm

sdrom33 wrote:
ON5HB wrote:

Funny is, I installed and MFJ SDR-switch the other day, the RSP1A's have the same signal as before, but the Icom7300 dropped by 10~20db in reception.
Why did the Icom drop and the RSP1A's didn't?
Bas, it is the rsp1a magic....It receives better because it has no mixers... : :oops:

In fact where Sdrplay specified they use mixers? They only use oscillators "to make them tick..."...ask Mike.
Come on, it mixes nowhere near the antenna input, where normal receivers do.
Also, most mixing is done DIGITAL! That does not send signals back.

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ON5HB
Posts: 140
Joined: Sat Dec 29, 2018 1:07 pm

Re: 3 dB HYBRID COUPLER/ISOLATOR FOR ANTENNA SPLITTING 100 KHz -10 MHz

Post by ON5HB » Mon Apr 22, 2019 9:01 pm

sdrom33 wrote:The right reply is that nobody in his senses would use a 50 Ohm connector on a 75 Ohm coax....come Mike, stop this nonsense and have a peaceful Easter, :D
And what if you do? How much losses does it give?
Will you notice? If so, how much?
And last. Prove it!

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ON5HB
Posts: 140
Joined: Sat Dec 29, 2018 1:07 pm

Re: 3 dB HYBRID COUPLER/ISOLATOR FOR ANTENNA SPLITTING 100 KHz -10 MHz

Post by ON5HB » Mon Apr 22, 2019 9:38 pm

sdrom33 wrote:Think with your own head, do not believe in false prophets, trust what you measure and see...I have gone to walk the dog...take it easy.
You do not get it do you? SWR is a non-issue.
Antenna-analysers are a non-issue too.

They do not say anything and they do not build good antenna's.

Example, analyse the best antenna in the world....the G5RV....your measurements tell it's crap....yet they are wrong, big time.

This has been proven over and over again...SWR is all over the place....yet they work. No program in the world has been able to improve it.
Not a single one.

All said it's rubbish....well?

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glovisol
Posts: 662
Joined: Thu May 10, 2018 6:42 pm
Location: Piedmont, Italy

Re: 3 dB HYBRID COUPLER/ISOLATOR FOR ANTENNA SPLITTING 100 KHz -10 MHz

Post by glovisol » Mon Apr 22, 2019 9:45 pm

To sdrom33, Mike2459 & ON5HB,

Please guys, do stop this discussion. I started this thread just to give technical information on 3 dB Hybrids and now it has been transformed into a debate that does not add anything to the matter at hand and I fear is only generating bad feelings.

- There was controversy on radiated local oscillator and I tried to clarify this matter with measurements and published results.
- There was controversy on the actual block diagram of the RSP-1A and I tried to clarify this subject by referring to a publication by SDRplay describing the issues.
- There was controversy on RSP-1A input impedance and I tried to clarify this matter by measuring the input impedance of the device and showing the results. Probably the specification page uploaded below has been missed by you all.

All the discussions you have done just bring us far from the original subject of 3 dB couplers. If everybody did this on any other thread, the treads would become a jumble of controversy instead of being peacefully informative and the Forum would be badly damaged.

PLEASE, STOP THIS!!
Attachments
ScreenHunter 386.jpg
From SDRplay "Detailed Specifications of RSP-1A
ScreenHunter 386.jpg (119.26 KiB) Viewed 2573 times

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ON5HB
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Re: 3 dB HYBRID COUPLER/ISOLATOR FOR ANTENNA SPLITTING 100 KHz -10 MHz

Post by ON5HB » Thu Apr 25, 2019 7:23 pm

The thing is, why do you need to isolate anything?

I asked you several times, yet you never answer.

I tested with a 50 Ohm splitter on my wideband websdr and signals went down, a lot.
Maybe it works for smallband but it does not when using 1-2MHz wide.

Also it doesn't work when using 3 bands, like 0-6MHz over 1 antenna, as the impedance will never be 50 Ohm over such a range.

For me it was useless and offering less signal to my users.
As such I stated the RSP1A doesn't need to be offered 50 Ohm, it doesn't.

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glovisol
Posts: 662
Joined: Thu May 10, 2018 6:42 pm
Location: Piedmont, Italy

Re: 3 dB HYBRID COUPLER/ISOLATOR FOR ANTENNA SPLITTING 100 KHz -10 MHz

Post by glovisol » Fri Apr 26, 2019 6:57 am

ON5HB,

I have amply replied to ALL of your questions in the course of this thread. Regarding the necessity for isolation I have replied not with my own words, but with those of Roger. I again upload the link for you to read:

https://www.sdrplay.com/community/viewt ... tor#p12269

For all the other questions my last post above is a summary of my detailed replies, which have been prepared, in the course of this thread, with painstaking care and a lot of personal work.

I do not know why you are being so provoking and confrontational both in my regards and towards other followers of this thread. Please stop this attempt at confrontation. If you wish to expose your own theories and experiences on antennas, RSP Receivers and VSWR you can start your own thread, there you could explain them at will. By your actions you have only succeeded in filling a thread devoted to the design and construction of 3 dB hybrid couplers with confrontation and extraneous arguments, completely confusing the technical information therein provided.

Please understand that the main motivation of this Forum is technical assistance and sharing of knowledge, not fights amongst those who shout strongest. If you insist I shall be compelled to report your provocations to the Site Administrator. You did so well, once, with another controversy, to invite all contenders to take it easy and go and walk the dog (as sdrom33 reminded you already). With a smile I tell you to please heed your own wise advice.

glovisol

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