datasheets and very high frequency stuff...

See also:

These LNBs are still made, I have a few converted ones for my 10 Ghz ham project..

Steve

On a sunny day (Thu, 2 Aug 2012 11:28:27 -0700 (PDT)) it happened Owen Roberts wrote in :

Very nice.

And some diagrams at last

Good

I am curious as to the local oscillators in these Ku band LNBs, there are basically 2, and I have seen diagrams where a PLL chip with a 25 MHz xtal was used to stabilize the frequency of those, google zlnb2001-4.pdf

Not 2 LNBs seem to be the same. The first thing I wanted was a 10GHz (and there about) frequency counter, I have a frequency counter PIC project with RS232 out,

so I am thinking 1:256 prescaler gets me in the 2 GHz LNB output, simple multiply the result by 256 and add the selected LO frequency and I have a 10GHz counter (in that band only). The other thing is a simple spectrum analyser for KU band: I was thinking 2 10 GHz oscillators with 2SC5508, mix with bat15 to a say 800MHz to 2.5 GHz sweep, lowpass, and then mix against the LNB output, lowpass few kHz. Sweep one of the 10GHz oscillators, and there you are:

10GHz >---------- fixed | 2SC5508 MIXER 800MHz-2.5GHz BAT15--lowpass------>----------> MIXER

xtal was used to

This is the link, the other one is something else entirely:

Jan,

Let me help you out with your quest. They eat power like crazy, but beat your DRO based LO against a cheap EBAY YIG.

Search Stellex and YIG on Ebay. Lots of 8-10 Ghz yigs get dumped cheap. Use a 1 or 2 Ghz bandpass as your IF, and if your feeling good, a 2nd LO for some selectivity.

If you want some control, pick up the synth board for the Stellex:

Steve

And here is your IF filter:

Last page of this link:

Steve

xtal was used to

have a frequency counter PIC project

multiply the result by 256 and add the selected LO frequency

800MHz to 2.5 GHz sweep, lowpass,

~9GHz >---------- |

times,

transponder, for example from Astra, today,

nearby.

opening angle,

lander to land in Reull Vallis,

inteligent??? life (was inclined to say THAN ON EARTH USENET).

Don't bother rolling your own spectrum analyzer. I got one of these a year or so ago. Actually paid more than the current price.

Mine had the battery pack, but it was crap. Now the advantage to having the battery pack is at least you get to rebuild the old pack. Mine came with a 12V adapter. This is basically field service engineer grade rather than HP gear, but it is good enough for hacking.

You will see these sold at two prices. The shop in Az "refurbishes" them. I refurbished my own. ;-)

The Avcom will drive a LNB directly. It has the choice of two voltages or no DC bias. It also supplies the 22khz needed for band switching.

This spectrum analyzer has an "infinite" persistence feature if you want to do sigint.

I kind of got ripped on mine since it was advertised to have ethernet, but the "recycler" didn't have that board. I did weasel a serial board from the seller. It has the traces for the ethernet interface, but not populated there. I can't get a schematic.

On a sunny day (Mon, 06 Aug 2012 23:52:17 -0700) it happened miso wrote in :

MHz xtal was used to

have a frequency counter PIC project

multiply the result by 256 and add the selected LO

800MHz to 2.5 GHz sweep, lowpass,

| BAT15

times,

transponder, for example from Astra, today,

nearby.

opening angle,

lander to land in Reull Vallis,

inteligent??? life (was inclined to say THAN ON EARTH

Yes, cool, I have seen somebody use something like that, while aligning a satellite dish (HUGE dish), that one also displayed all info (sat name etc).

He charges 275 $ shipping to my country, same old story (got the cry cooler (super conducting filter) it mentioned similar high shipping costs, but then he send it in a different way and that saved a 100 $ or so.

But now for something different, did you notice that in the above diagram, if you leave out the LNB stuff on the right, you get a zero to 3 GHz spectrum analyzer (for zero offset at minimum in the oscillators)? This is why I use 2 oscillators and the difference frequency. Need a bit of input wide band gain, but that is not really a big deal.

Yes the horizontal / vertical polarization and band switch, but that is just simple to design. LM317, some transistors, 555 oscillator or something, perhaps PIC interface.

I did a RS232 to ethernet UDP PIC project with some ethernet modules from ebay:

just so I could connect via the LAN to some of my RS232 projects... It is a bit slow and buggy, but for some stuff it works. the software needs updating, but I am in for years with cool projects now :-)

I could not resist taking a piece of paper and doing the DVB-S DVB-T modulator design. There is incredible stuff on the web now, a lot changed in the last few years when I was not looking, my last go at it was in 2004 IIRC. The amateur radio community is now also really into DTV it seems, I recommend reading these links:

This guy did a lot in FPGA, open source verilog code: There is cool open source and also some close source free software to make a DTV stream: google gbdvb_bin_3.4_LINUX_i686.tar.gz google Avalpa Broadcast Server

That FPGA stuff is very nice, and I thought of putting more into the FPGA to make it output RF, I would love to do an article on quadrature modulation explained in the time domain, I had great fun with that in the past for PAL TV and got some great feedback from people who loved it, rare on Usenet... I think I can do the IQ (nothing to do with intelligence lurkers, but maybe it has?) directly in HDL. Then I have 2 other projects, one physics of the third kind, parts just came in, and the GPS stuff of course, and the auto pilot glider control, and... If Usenet still exists by the time it all works I am sure I cannot keep it all to myself, and will tell you about it. Fun:-)

I'm surprised Golden West doesn't have a slow boat to China shipping plan, especially for those Avcom units. They bought them racked from a military project. That is why they are missing feet. Of course the good news is they didn't see a lot of rattling around the service person's truck. Anyway, they had close to a 1000 units. They will be sellingg them for years.

Also in your quest for cheap mixers, ebay sells what appears to be MDS downconverters. I have a few laying around, waiting for me to hack. They convert 2.15G-2.162G to 116MHz to 128MHz and 2.5g-2.685G to 222-408MHz. Looks like they are no longer on ebay.

is similar.

On a sunny day (Tue, 07 Aug 2012 19:05:07 -0700) it happened miso wrote in :

Yes, I considered and looked up some pre-build stuff, there is still some on ebay, and I have a box full of fine RF stuff. I prefer to design and build my own. Bought some down converter (to 2 mtrs) years ago at an amateur meeting, dunno what happened to it. In the sixties? I designed a nice little TV tuner... It should all come back... :-) For higher frequencies the striplines should be shorter, that is all? Some co worker in the seventies gave me a nice book on radar and RF cavities, it clicked then. There really is a lot on the net on RF, the web is a real goldmine!

There are programs to design stripline.

It's much more efficient to "repurpose" old gear than to start from scratch.

Incidentally, if you need to build your own horn antenna, there is an old 16 bit DOS program on the internet. It runs in DOSBOX.

On a sunny day (Wed, 08 Aug 2012 20:05:14 -0700) it happened miso wrote in :

I need to get some feel, so I will solder and measure.

I am not so sure, but will thest that idea :-)

Yes

On a sunny day (Wed, 08 Aug 2012 20:05:14 -0700) it happened miso wrote in :

PS, much to my surprise 3 LNBs already arrived today, from Honkong. Just a few days, faster than the post here....?

So, I opened one (have not done any functional testing yet), and it was easy to open but a zillion of what looked like small crystals dropped out, were all in the horn, all over the place:

First I thought: Glue, then I thought silica gel, then I thought crystallized glue again, as a bigger piece was still intact. You Never Know (tm) what China uses for chemicals to copy cat western products like baby milk and toothpaste, so I treated these pieces very carefully, as they ever divided into smaller pieces, no its not asbestos, but then again.

Anyways, the lid came of easy, 4 screws (the other 2 adjust the LOs, did not touch those:

Any idea what the big bar in the horn is for? You can see the 2 antennas at 90 degrees, those are much smaller:

And finally here a bit better pict-jure of the PCB (we have all been waiting for ;-)), it shows a lot:

I will have to look up that SP3211[Q??] chip.

Maybe these are so cheap because those little crystals are really failed glue, and in the horn ruin the RF properties? Make it leak?

Or maybe because everybody only wants .1 dB noise LNBs and these have .3dB... (Just for fun I think mine, up there, has .5 dB, so and I have huge signals), so all sales hype, unless you have a 20 cm dish perhaps?

77.GIF

crystallized glue again,

products like baby milk and toothpaste,

smaller pieces, no its not asbestos, but then again.

not touch those:

If i am not mistaken it is a mode alignment forcing doohickey. Forces a particular TE mode in the antenna. At least that how it was explained to me many decades ago.

waiting for ;-)), it shows a lot:

glue,

.3dB...

signals), so all sales hype,

On a sunny day (Wed, 08 Aug 2012 20:05:14 -0700) it happened miso wrote in :

PS, Analysis of the LNB shows the control chip is what is likely a second source version of the ZNBG3211:

Had difficulty finding a datasheet of the SP3211, but then it occurred to me, this must be a ?Sipex? version with the same type number range (numerical part) as the (not seen before) ZNBG series, and YES! This is a GaAs and HEMT FET controller, it also has a Sallen key 22kHz detector for band switching, and a voltage level detector for the polarization selection.

I think I have all parts covered now, waiting for my 1:256 3GHz prescaler chips so I can measure frequency.

Sorry if I crashed your moon lander ;-)

PS, Looking at the use of the little dielectric resonators as oscillator, I did some web searching and found this site, that I think is pretty good:

As my intention is to frequency sweep one of these DROs, I just found the howto right here, half wavelength with 2 varicaps close to the DRO, see fig 5a.

I think some RF transistor Cbe can be used, where Cbe varies with collector voltage, been there, done that:

Jan,

just put a grounded metal plate above the DRO, the same diameter as the "puck" and move it up and down about 2 mm. It will sweep 500-1000 Mhz or so, Another trick is to place a thin ceramic disk on top.

As for antennas, start at w1ghz.org

For a better prescaler, go to Ebay and search for Hittite.

Steve

On a sunny day (Fri, 10 Aug 2012 11:10:18 -0700 (PDT)) it happened Owen Roberts wrote in :

Right, that was one idea I had, I have this little ear piece, bad sound quality, with a metal (I think) membrane, magnetic. Some DC on it moves the membrane back and forward, like a speaker. Wanted to mount it close to the oscillator, but then I have to make a new board I think. Doing it all electronics is of course nice and probably more stable (microphonics?)

That is a very nice site, it will take me some time to read all that. Very nice!

I did look up the Hittite products on ebay, but the NEC UPB1505GR-E1 1:256 seems to meet my needs at about 3$, I have 2 coming my way. If I cannot get it to work (but why not?) I can always try something else.

The other thing I am looking at, is the wave form and amplitude issue. Sure you can make a 10GHz or there about (or about 3 GHz) sampler, (as frontend to an about 20MHz old analog scope) but samplers are only needed if you want to look at once in a while impulses (low repetition rate) and / or store the samples. Just mixing down preserves, if done right, the amplitude and wave form relationships, or in more down to earth terminology look at IF output mixed down to within scope bandwidth. The difference between a sampler [head] and a mixer is largely 'academic' anyways, I am more interested in the waveforms and amplitude versus frequency etc, than in impulses. For DTV at about 2 Msymbols/s that should really be good enough. GPS has even lower bitrates. Fun, I see lots of fun experiments, and that website you refer to will help too I am sure.

Thanks for the links and suggestions!

Not the case -- mixing does not respect the harmonic content of a waveform, which is typical of its waveshape. A square wave at 1GHz has harmonics at

3, 5, 7, etc. GHz. If this waveform is mixed with, say, 0.9GHz, you get sum and difference at 0.1, 1.9, 2.1, 3.9, etc., of which only the fundamental (and its sidebands) appear after lowpass filtering.

Note that sidebands are typical of what's going on from cycle to cycle, while harmonics are typical of what's happening within a cycle. You can run AM or FM through a variety of nonlinear circuits and recover the original sidebands, because they are not an instantaneous sort of thing, but slowly changing. Nonlinearity destroys harmonic profiles (adding more harmonics, introducing IMD -- of which mixing is arguably a special case, etc.).

Sampling is equivalent to mixing a signal with a repetitive transient waveform (usually modeled as a Dirac delta 'spike'), which as an eigenfunction of the Fourier transform, happens to have the same representation in the frequency domain (i.e., evenly spaced, equal height spikes, in time, convert to evenly spaced, equal height spikes, in frequency). In this case, with a sample rate of 0.9GHz, you also get its harmonics at 1.8, 2.7, 3.6, 4.5, 5.4, 6.3, etc., which mix with the respective harmonics of the hypothetical squarewave, producing 0.3, 0.5,

0.7, etc. GHz in the baseband, and many others at higher frequencies. (Notably, sampling causes the same scattering effect at all frequencies, so that in the 0.9-1.8GHz band, *two* images of the original signal's harmonics are seen, and so on!)

Of course, the best way to generate a sampling frequency at a small delta F from the signal of interest, is with a controlled timer. Technically, you really want a modulated PLL or something like that, but a timer is nicely general purpose because it can be triggered on arbitrary points, and in an oscilloscope, it doesn't matter that your readout isn't a whole number of cycles, indeed it rarely lines up to a calibrated range.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

Oh go such a lollipop, of course this is true, but if you had bothered to look at the diagram I posted in this thread you would have noticed the low pass smart ass.

So if we look for example at 10GHz and mix with a modulated signal 9989MHz

+-10MHz, mix it, the 19 GHz and next to it is filtered out by the low pass, and only 10MHz to 30 MHz appears after the lowpass.

It is called direct conversion, and I can assure you that the waveform is not changed (the modulation on it). In fact superheterodyne does not change waveform in any way considering you do not cut bandwidth. That is how AM radio works remember?

1 MHz -> 475 kHz, AM detection of the WAVEFORM. The 470 kHz IF has here the bandwidth limit. And you know what? replace the mixer by a sampler, and everything still keeps working like it ever did.

And the other side around, have you ever looked at the aliasing in a digital SAMPLING scope? Exactly the same. get a life, and understanding, buy a brain.