Gunnplexor satcan question

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OgreVorbis
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Gunnplexor satcan question

Post by OgreVorbis » Sat Jun 22, 2019 1:59 pm

Hi,

I am from the US and there is very little info on this here. I just bought this gunnplexor: https://www.ebay.com/itm/X-BAND-TRANSCE ... 3685069830

Will it work with this satcan here? https://djmtx.weebly.com/store/p2/Satca ... eiver.html

So can I just capacity couple the audio into the power supply for the gunnplexor? How does the modulation normally get applied?

I also purchased an empty gunnplexor cavity because I thought I might need a higher power diode. This diode looks good: https://www.ebay.com/itm/MATCHED-PAIR-C ... 1272015905

It is a slightly lower frequency 9.5 instead of the normal 10.5. Will it work? If not maybe there is a source for a gunnplexor with > 8mW
The distance is about 5km line of sight.

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teckniqs
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Re: Gunnplexor satcan question

Post by teckniqs » Sat Jun 22, 2019 7:54 pm

Never used those Satcans before but they were recommended by a well known Dutch builder (on here) for someone who needed a Satcan for 10 to 11Ghz a few years ago.

....I would highly recommend a much larger/longer flange (waveguide) for that Gunn, as it only has the very small C&K alarm detector system short-range type fitted on it.

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Re: Gunnplexor satcan question

Post by OgreVorbis » Mon Jun 24, 2019 12:53 am

OK, good. I had to look more carefully at the board because the page doesn't say 10G anywhere, but now I see it on the board, so it should work.

I've collected some schematics from google images. They all use somewhat different methods, but it doesn't seem too complicated.
Is there a way that the modulation is typically done over here?

For the receiver, I got a Ku band LNB cause the X band ones are hard to find and expensive. It says 10.7 ~ 12.75 GHz (LO : 9.75 & 10.6 GHz) so I think it should work? So I just hook the coax from the satcan to the LNB and it sends RF and power for the LNB, nothing else needed?

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Re: Gunnplexor satcan question

Post by OgreVorbis » Mon Jun 24, 2019 1:00 am

Just realized that site with the satcan doesn't work at all; the contact page is completely blank and when I try to add to cart, nothing happens.

Does anyone know the guy who sells them?

Albert H
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Re: Gunnplexor satcan question

Post by Albert H » Mon Jun 24, 2019 11:06 am

I always used to buy sat cans from Sendz Components in Shoeburyness. They sell lots of parts removed from old gear and charge next-to-nothing for them. Contact them to see if they have anything left.
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shorty
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Re: Gunnplexor satcan question

Post by shorty » Mon Jun 24, 2019 7:22 pm

A forum member on here or it could have been the old radionecks site, i can't remember who it was, posted this schematic for a modulator circuit to apply audio to your micrwave horn, it works well i've used it a few times.
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Re: Gunnplexor satcan question

Post by shorty » Tue Jun 25, 2019 10:29 pm

Ogrevorbis try hf electronics for a satcan, i believe he has some sharp ones available.

www.hf-electronics.nl

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Re: Gunnplexor satcan question

Post by Albert H » Sat Jun 29, 2019 11:35 pm

shorty wrote:
Mon Jun 24, 2019 7:22 pm
A forum member on here or it could have been the old radionecks site, i can't remember who it was, posted this schematic for a modulator circuit to apply audio to your micrwave horn, it works well i've used it a few times.
That's pretty much the circuit that I came up with in the 1980s. You can use frequency-selective bypassing of the first transistor to introduce pre-emphasis if you need it.
"Why is my rig humming?"
"Because it doesn't know the words!"
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Re: Gunnplexor satcan question

Post by Shedbuilt » Mon Jul 01, 2019 6:36 pm

I did it slightly differently. I used an op-amp, trimmed the reference voltage to the op-amp, with an emitter follower; to drive the Gunn (current dumping). Where pre-emphasis was required, I did it in the negative feedback loop.
Also used to buy those sat-cans from Sendz (LNBs too if I remember rightly); back in the mid-nineties.

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Re: Gunnplexor satcan question

Post by OgreVorbis » Fri Jul 05, 2019 12:06 am

Albert H wrote:
Mon Jun 24, 2019 11:06 am
I always used to buy sat cans from Sendz Components in Shoeburyness. They sell lots of parts removed from old gear and charge next-to-nothing for them. Contact them to see if they have anything left.
I'm not in the UK and it doesn't seem like they have an online shop.
shorty wrote:
Tue Jun 25, 2019 10:29 pm
Ogrevorbis try hf electronics for a satcan, i believe he has some sharp ones available.

www.hf-electronics.nl
I had a look, but I don't see any satcans on there.
I think I might go with this (a little expensive): http://users.otenet.gr/~nsavvas/tuner_en.html

I got a temporary setup just using a handheld icom receiver as the "satcan". It was good enough for a test.
The gunnplexor sends pretty good. I set up an old satellite dish about 30 meters away and it works well. This is without a horn, just the tiny thing about 1cm that it came with. I'm pretty impressed with it only being 8mW. I'm going to get a bigger horn and do the real long distance test in a week or so.

The only problem I am having is the gunn is drifting a lot. After being on for 15mins, it was still drifting down. It moved about 10MHz before I turned it off. How did they used to keep these things locked? I am assuming it is a temperature thing, but maybe my bench supply isn't stable enough. I'm thinking of using a TEC with a temp controller, but I don't know if that's the best way. Is there like a PLL type thing for it?

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Re: Gunnplexor satcan question

Post by yellowbeard » Fri Jul 05, 2019 12:46 am

He has a couple of hundred in stock for €5 yoyos a piece - though you have to use the search to find them.
https://www.hf-electronics.nl/Webwinkel ... atcan.html
:tup

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Re: Gunnplexor satcan question

Post by RF-Head » Fri Jul 05, 2019 5:43 pm

That one i have in my shop has only a 479.5MHz output and no audio output
I had bought them and thought it has audio out but no :(
But i have sharp cans (short and long) in stock and i have them on ebay

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Re: Gunnplexor satcan question

Post by OgreVorbis » Fri Jul 05, 2019 10:55 pm


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Re: Gunnplexor satcan question

Post by teckniqs » Sat Jul 06, 2019 10:52 am

RF-Head wrote:
Fri Jul 05, 2019 5:43 pm
That one i have in my shop has only a 479.5MHz output and no audio output
I had bought them and thought it has audio out but no :(
But i have sharp cans (short and long) in stock and i have them on ebay
The one you recommended doesn't work? lol :whistle

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