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Hello all.

I have been thinking of building a 20.1 mhz rx for JOVIAN for quite a wile now, been considering kits and the project that Philip is building now.

But lately I have got more interesting in, as i study it, building a "408 MHz All Sky Survey" radio telescope, there are tons of material out there about this subject. Have any body here build a system like that?

I came across this project:

Link

Amateur Radio Telescope Plans

Can be build for a reasonable price for an hobbyist.

Here is one that can do the most, more work, more expensive:

Link

Science Workshop

Quoting:

"YOU CAN ALSO USE THIS DEVICE TO DO RADIO ASTRONOMY AT C-BAND FREQUENCIES.........IF YOU ARE AIMED AT A TVRO SATELLITE, YOU WILL SEE DATA FROM ALL OF IT'S TRANSPONDERS.......IF YOU ARE LOOKING AWAY FROM THE CLARK BELT, YOU WILL BE LOOKING AT A CHUNK OF SKY WITH A WIDE BAND RECEIVER."

From [removed word] Goodman's (WA3USG) article "Building a SETI Station."

Link

Science Workshop

Great project!

Regs

Jogeir

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It's certainly on my list to setup some kit like this...

Once I've got my HF stuff finished I'm going to get working on this.

Beauty of gear at this frequency is that you can work with

physically smaller aerials....

wether it will have quite the interest pull of the Jupiter/solar

work, I'm not sure...

Another thing to consider is simple VLF gear to monitor disturbances caused by solar activity (SIDs)

Mine is a simple loop aerial plugged into my puter sound card

and I monitor around 19KHz...

Loads of things to build and mess with in this part of the hobby:glasses1:

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Philip,

yes it sure is, like to do lot of this stuff. We do have a nice place (and 'electric noise' quiet, house, and the shack and tower for water tank, and a big 10' x 10' platform up there for antennas) in the Philippines, not 100% finished yet, but it soon will be. At present I am in London, as it is wet season in Asia, but going back soon. I do have a VLF-3 receiver, but would like to do some SID logging as well. Can you please post some details about your SID loop antenna, and how you connect it to you PC, isolation transformer, amp, ADC?

I do have a FT-857 so i can use it for 408 mhz, and also for 20.1 mhz, but as I am a ham i will not like it to be tied up to those frequencies all the time, hens i like to build separately receiver for different RA receivers. I will keep you updated as I build and opperate my stuff there in the Philippines.

Regs

Jogeir

post-21274-133877492459_thumb.jpg

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The loop is built like this one

lop.jpg

Didn't find a need for a transformer as the loop straight into the

mic socket produces some very nice signals from the UK

submarine base transmitters...

If I was to mount the loop outside then there would be a need for

static protection and/or a pre amp but as it is, it works well...

Started to build a probe receiver for whistlers and spherics and stuff as well

73's de G4JVF :D

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Philip,

thank you for the information. Are you using polypropylene capacitors there.

I saw some were how to find the resonant frequency of a loop/cap like this,

but I forgot where and how.

Link up a JOVE and a SID receivers like this seems like a good idea SOLAR RADIO TELESCOPE

Regs

Jogeir

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Yes, any type of capacitor will do...

I used an 8 way dual inline switch and I added a 47pf section as well plus a 500pf variable capacitor across the lot for fine tweaking.

They can have quite fine tuning these big loops....

Somewhere, I've got a link to a loop turns calculator.

I'll post it if I can find it:)

That gyrator looks good, an interesting way around using coils :D

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One thing is to calculate the resonant of a coil\cap, you have a clue where you maybe are, but measuring it would be better, as Philip say "They can have quite fine tuning these big loops...." Hook up yout Sinus generator, scope and frequency counter in parallel over you loop\cap and tune your generator until you see that you have resonant on you scope and read the resonant frequency on your frequency counter.

Guess most of you are "optical" astronomers so you do not have those instrument, but all these is so cheep second hand now on eBay and othe places, so most hobbyist (including me) can aford to buy it. Just bought two oscilloscopes for about £10 each to use for my Radio Telescopes that I pland to build.

Regs

Jogeir

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Everybody.

The project is going slow and it have been changed from 408 MHz to 611 MHZ. The tuner board kit from MTM Scientific has arrived, time to plug the soldering iron. This is a nice and simple kit, it can be classified as a beginners kit, anyone with just a little soldering experience can put this together.

Regards

Jogeir Lindseth

post-21274-133877510032_thumb.jpg

Edited by baron von vulpes

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Everybody.

The project is going slow and it have been changed from 408 MHz to 611 MHZ. The tuner board kit from has arrived MTM Scientific has arrived, time to plug the soldering iron. This is a nice and simple kit, it can be classified as a beginners kit, anyone with just a little experiece soldering experience can put this together.

Regards

Jogeir Lindseth

Playing radios is fun isn't it!.. I assume you are taking ESD precautions when building. (hoping I'm stating the obvious)

Derek

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That's a great kit...good price too..

What sort of aerial are you going to use?

Presume you could use a high gain UHF aerial for digital TV..

Keep us posted with your progress:glasses1:

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Derek, Philip

Yes sure is fun to play with those things, especial this one as it is so many thing you can do with it beside using it as a Radio-telescope, you can use it for a Spectrum Analyzer to scan the frequencies of your interest. I am going to do both on the same unit, switch the PICAXE. The red wires are for the AGC, puting 12v to the SIF, VIF unit as shown, will disable the AGC, you can also use a potentiometer to make it stepless.

As you can read from their homepage, there is not so much to it to reprogram the PICAXE for scanning or program it for an another frequency. Can do a lot of experimenting here.

As for the aerial I was in the beginning planing to use a yagi for 611 MHZ (or 408 MHz) but now I think I will build a bigger log periodic antenna so I can cover wider band-with.

http://www.uom.ac.mu/events/2010/mrt/first_anniversary_of_mrt_based_CALLISTO_spectrometer.pdf

I have put together the kit and did started to make a triple power supply 5v, 12v and 30v, using a LM7805, LM7812 and a LM317 for the 30v. The transformer and rectifier is from a 12 mains adapter, going to use a separate one for the 30v supply. Going to finish the power supply today, and start to test the tuner, exciting, always exciting the first time you fire up your home-build gear!

That's it for now, will keep you updated, and as Philip says, this is a nice kit to a nice price, the pcb is thick and of very high quality double side. And for you who are thinking of starting with a 408, 611 MHz telescope this is the way to begin.

(well, that is my opinion)

Best Regards

Jogeir Lindseth

post-21274-133877510995_thumb.jpg

post-21274-133877511004_thumb.jpg

Edited by baron von vulpes

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Won't you need a cross-polarised rather than a straight Yagi or LP?

David

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David,

frankly, I do not know what is best, so I have to start somewhere, can you tell me why you will prefere cross-polarized before a yagi or a log-periodic antenna. All the papers I have been reading they are using yagis, quagis or log periodic antennas, "The Mauritius e-CALLISTO Helioradiospectrometer" (phu) using the antenna I am planing to copy.

See the link to the pdf file on my other posting earlier today. Frequency rage from 20 - 860 MHz. Umm, maybe I can use this for JOVIAN on 20.1 MHz too...

Please keep on giving input and suggestions, that what this forums are for, teach what you know, learn what you do not know.

Best Regards

Jogeir Lindseth

post-21274-133877511011_thumb.jpg

Edited by baron von vulpes

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My mistake for assuming earth-bound signals would be 'mixed' polarisation!

The LP looks quite a beast, but you could knock up a small Yagi in very few hours if you have a pillar drill. I used to get my ali stock from B&Q. I used sleeve baluns for matching (piece of RG213/4 inner, sliding in ali tube with simple clip to attach to driven element, 'live end' attached to N type connector mounted on angled piece of ali).

Good luck and will watch progress with interest!

David (ex M0XUK)

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Everybody!

Well, I think I will scale down the Log Periodic antenna a bit, the tuner tunes from 55 MHZ to 860 MHz, but even that will be a quite big antenna.

18 element, Axial Length: 4.522049174202821, Longest element: 3.30444441.

May be, as Philip suggested, an UHF TV antenna will do the trick?

Even though it is not covering 408 MHz.

Channel coverage:21-69

Frequency range: 470 - 862MHz

Antenna gain: 14-16 dB

Beam width (degrees): H30 / V33

Front - back ratio: 26 dB

Impedance: 75 ohm

Antenna length: 2210mm

£ 49.00 from Maplin

The uhfscan.bas program from MTM Scientific runs from 473 to 803 MHz, so it will be a nice antenna to scan those frequencies, I will decide later.

First I have to make the tuner run properly. Did the first test today morning. My "30V" is not quite 30V, I can get only 28.2V out from a 12V transformer

and a voltage tripler, if it is matter or not I do not know, but I am not quite happy with it.

Anyway, when I switch it on I get about 150 - 200 mV out from the INA 122 DC amplifier, and it slightly rise when I touch the antenna with a bare wire.

And white noise in the Audio Out. I hope that's indicate that the tuner is working properly.

Have to figure out what to do with the 30V supply before I start to box the project, in a vinyl box from Maplin,

same as Philip used for his TenTec 20.1 MHz project, they are OK for £ 9.99.

Best Regards

Jogeir Lindseth

post-21274-133877511492_thumb.jpg

Edited by baron von vulpes

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Hello Everybody.

While waiting for the parts for the new 30v power-supply I continue studies of those very interesting TV tuners.

You can also make a Radio Telescope (wide band receiver, spectrum analyzer) by savage an analog tuner from an old TV set or a VCR.

In a simple way it can be done like the attachment picture here. But in practice you will have to use two ten turn potentiometers, 10k coarse, and a 500R for fine tuning.

IF out goes to the detector and a DC amp, ADC and then to you computer.

Adding a sawtooth sweep generator to VT will make it a simple spectrum analyzer.

There are probably members here that know more about this than I?

It would be nice to know how many of you are following this project, I know Philip and David (ex M0XUK) do,

and how interesting this "branch" of astronomy are for you. Please write a line or two! I love feedback :-)

Positive or negative alike.

Best Regards

Jogeir Lindseth

post-21274-133877512079_thumb.jpg

Edited by baron von vulpes

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Versatile things these old tuners...

Reminds me when we used to mod VHF tuners for aircraft band and such...

What's the plan when you get it working, what will be your target of choice and what charting software have you decided on?

I'm experimenting with a remotely power amplified loop for Jupiter and Solar but that's been held back by weather conditions.

Also, I'm nearly finished with my SDR receiver 1.5 to 30MHz build which I hope to try with astro reception given it's uber stability frequency wise.

Keep up the good work

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Philip,

yes you can have a lot of fun with those TV tuners, planing to have one more in the same box, an analog one. Will see what I will use it for, Antenna Analyzer? An ADC will go in the box as well, software I do not know yet,

any suggestions? And the first target goal will be Cassiopeia A, the strongest radio source aside from the Sun in the sky. Will sooner or later need a LNA as well, did not find any good project so far.

A nice SDR receiver is definitely on my wish list, but I have a couple of project going at the same time all ready now, so later. Guess you can call those TV tuners SDR as well :-)

Your remotely power amplified loop sounds interesting, 20.1 MHz I presume. You mind tell more about that one. As for the JOVIAN receiver I think I will go for the Fox Delta kit, about £100 assembled, as their kit is not ready yet.

I think that price is good, as you get a frequency counter, and the ADC is build in, the MAX187 chip is not included though, and it is boxed.

I am in London now, will stay here till February 2011, and then go back to Philippines, and start to put up my antennas for 20.1 Mhz and also for the RA project.

Up in my tower (see picture, of the tower with the tripod) I am planing to put up a Moxon antenna with a rotor for the 15 meter amateur band and I did read they work good for JOVIAN as well. Picture taken from my veranda in second floor. Can't do much here in London except for building the receivers and prepare things.

Hopefully parts from Maplin will arrive today, so I can continue.

Best Regards

Jogeir Lindseth

post-21274-133877512489_thumb.jpg

Edited by baron von vulpes

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Ok on everything...

Quite fancied a Moxon here but when I paced out the size of it, I

decided against.

The loop idea came from this design

HF Active Loop Antenna

It's untuned and works very well indeed on my general coverage

SDR.

In fact it's so good, I'm thinking it will out perform a dipole for Jupiter.

Compared with any other aerial I have, the noise floor is very low with the loop so in theory the weaker astro noises should stand out more plus, it's directional ...

A lot more tinkering to do but very impressed so far.

This is the kit SDR receiver I built and am waiting for a transceiver kit to arrive in the post

Ensemble RX II Builders' Notes

I envy you that tower, what a great base on which to tinker with aerials..

Anyhoo, good luck with it all and keep posting the results..

73 de G4JVF

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Philip.

The active loop is a very good idea I think, haven't read about any body that have done this before, are use using it with the diamond shape as well?

Measurement of the sides? And how high up from the ground do you plan to put it up, got interested in this one :)

Post a picture when you get it up!

SDR receivers, what about modifying a Soft Rock Lite II, change the x-tal and modify the band pass filter to center frequency of 20.1 MHz?

"A crystal of about 26.8 MHz would give a 1/3 sub-harmonic sampled center frequency of 3* 26.8 / 4 = 20.1 MHz. For higher frequency use,

1/3 sub-harmonic sampling needs to be used since a crystal of 4*20.1 MHz would be hard to get.

The 20m BPF may be modified for 20 MHz operation by a change in capacitor C3 from 47pF to 47(14/20.1)(14/20.1)= 22pF.

C4 value would change from 680pF to 680(14/20.1)(14/20.1)=330pF.

The C10 and C11 values used for the 40m case would work for use with a 26.8 MHz crystal."

Source Tony Parks

Rocky, the software for the radio will work with that center frequency.

Do you think it will make a good JOVIAN receiver?

Attached is the schematic for the Lite II Combined kit.

The tower is many ham radio operators dream (including me) I think, I a country like Philippines I can do thing like that, but not in any European country.

So I am very pleased with my Shack and tower, yes lots of space up there for antenna and stuff.

Not much progress with the CATV project, made a 386 amp for the audio output yesterday, that's all.

Best Regards

Jogeir Lindseth

post-21274-133877512611_thumb.jpg

Combined Lite II 6_13_10.pdf

Edited by baron von vulpes

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Having several emails now, discussing with Tony Parks about using his small receiver for 20.1 MHz he will send me a a ready build one for evaluating.

He have a moment only one x-tal for that specific frequency he can only make one at moment. But if more of you are will like to order from him later,

he will sell them for $32.00 each, that is a very good offer. He will also sell kits, $22.00, but is it make uses of SMD components it is not for me.

I think in combination with the active antenna Philip is experimenting with, this will make a "rock" good JOVIAN receiver.

Best Regards

Jogeir Lindseth

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Hi Jogeir

Re the Softrock, I bought an early one which was for 15 Meters.

I think it was removed as it suffered from breakthrough of 40 meter signals.

However, I decided that it would be ok with a better filter up front.

Tony kindly sent me a crystal (tiny surface mount one) to centre it around 20 MHz.

I have yet to move forward with it as I got side tracked with the Ensemble RX.

Re the loop, I must admit I was a loop sceptic but no more, it's an amazing antena producing a very low noise floor compared with my other more conventional aerials.

Some pictures of it below.

It's cross arms are 2 meters across and the element is made from 5mm fence wire.

It's nailed to a tree, hanging 300mm from the floor for testing.

I'm using it to monitor WSPR beacon signals and it's hearing 1watt transmissions from affar as Florida and near to Cambodia.

Certainly warrants experimentation for Jupiter as the low noise floor and it being directional should favour it for this purpose.

Maybe an amplifed but tuned one for 20.1 Mhz would work well..

Some experimentation with the amplifier components might achieve better balance/noise reduction

All good fun:headbang:

loopamp.jpg

lp1.jpg

lp2.jpg

lp3.jpg

Edited by geppetto

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Everybody!

Well, I think I will scale down the Log Periodic antenna a bit, the tuner tunes from 55 MHZ to 860 MHz, but even that will be a quite big antenna.

18 element, Axial Length: 4.522049174202821, Longest element: 3.30444441.

May be, as Philip suggested, an UHF TV antenna will do the trick?

Even though it is not covering 408 MHz.

I bought a pair of 100MHz to 1GHz LPs (a pair so I could calibrate them) and used them down to 10MHz, they were still pretty good at 50MHz, maybe +7dBi. Nominally they were about +12dBi and worked out pretty flat response. That was over 10 years ago, but these things are always in some sort of demand.

I'll have a glance online to see if I can find anything similar

Derek

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