Build a SUPRX tuner?

[forr]

OOPS ! previous messagfe sent before finished

In France we are very lucky with programs : I think France Musique is a real reference of what can be done with FM, particurlarly in direct broadcasting. There are at least six other stations whose sound is really first class with absolutley no audible compression.

I own a Leak FM mono tuner (with no component ever changed, as far as I can see). This tuner is rated as the best ever made by HiFi World (England). I only compared its mono sound to other recent stereo tuners. Till now, I think HiFi World may be right.

~~~~~~~ Forr

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[AuroraB]

At least here in Europe, it seems like the government owned stations have a generally higher technical quality on the transmissions than the purely commmercial ones, which often sounds really horrible-- even the best of music can apparently be destroyed! Just out of curiosity-- the US never had governmment owned stations- did they???

[jackinnj]

QUOTE]Originally posted by Algar_emi

To build and desing a tuner you need RF test equipments. I have maybe 100K worth of RF test gears and you would need most of that. RF FM generator, Modulatio meter, RF voltmeter, FET active probe, High frequency frequency counter and maybe a spectrum analyser for Front end and IF testing. [/QUOTE]

Actually, the Sencore SG165 and an o'scope are about all you need. A lot of the parts can come from repurposed ham radio gear and cannibalized tuners.

A good book to start with is "Experimental Methods in RF Design" -- this is an ARRL publication so there is a good likelihood of it being available in a library (at least in the US, possibly Canada), there are excellent Radio Society of Great Britain books in the same vein.

What the world needs is a good Gallium Arsenide front end.

[DragonMaster]

Just out of curiosity-- the US never had governmment owned stations- did they???

I don't think they do. Canada does own tons of stations(CBC). Wait a minute I count how many of them... 100 radio and 40 TV stations ?!? yup, tons of stations. And these don't have crappy sound. THe only thing is that over half of them were AM stations turned to FM, which means they are mono.

I guess I'll get a tuner that's able to DX a bit, one of the channel I listen is using a 100kW omnidirectional transmitter antenna 80kms away, it's hard to get good reception.

EDIT: Oh, a post was posted while I was writing. jackinnj, thanks for the info.

[AuroraB]

GaAs front ends are hardly needed at 100 MHz....modern bipolars and FETs will do perfectly well....
the trick lies in the IF part.... todays simple quadrature detectors are just not good enough for high linearity...=quality.

Actually- modern technology in the form of DSP should be the way to go, -- by nature - it will however be digital....with a couple of DACs at the end...

EDIT: without googling .... there probably are kits out there still... Vellemann used to have a rathere fancy one ( haven't seen or tried it, though..) but they are most likely of mediocre quality, at best......

[jackinnj]

Originally posted by DragonMaster


I don't think they do. Canada does own tons of stations(CBC). Wait a minute I count how many of them... 100 radio and 40 TV stations ?!? yup, tons of stations. And these don't have crappy sound. THe only thing is that over half of them were AM stations turned to FM, which means they are mono.

I guess I'll get a tuner that's able to DX a bit, one of the channel I listen is using a 100kW omnidirectional transmitter antenna 80kms away, it's hard to get good reception.

EDIT: Oh, a post was posted while I was writing. jackinnj, thanks for the info.

WNYC was owned by the City of New York, WBOE in Cleveland was owned by the Cleveland Board of Education. In the frequency range of 88MHz to 92MHz many of the stations are owned by public universities (if you like Classical, listen to WKSU -- Kent State University in Ohio.)

wrt GaAs front ends -- these are used on 2 meter receiver preamps all the time.

[AuroraB]

Originally posted by jackinnj



wrt GaAs front ends -- these are used on 2 meter receiver preamps all the time.

I know....I hold an advanced license.......
Not quite all the time, -but that doesn't make them necesseary, as there are other parts of a broadcast receiver that are far more important to the final quality

[DragonMaster]

I found a sg165 on ebay currently @ 35$.

What's the purpose of a signal generator? Alignment for sure, but what kind of?

Anyways, I just joined FMtuner Yahoo group, and I see people talking about Sansui TU-717 everywhere on ebay.

[AuroraB]

the signal generator is a radio frequency tone generator, usually with extra circuitry for modulating the carrier.
Useful for testing sensitivity, and aligning the RF and IF amplifier sections.. a spectrum analyzer and tracking generator is better for aligning filters and tuned amplifiers....
For detector alignment a wobble generator is the tool....

Well---- nity-nite for now....
it's well past midnite in my corner of the world........

[DragonMaster]

Hmmm... tons of generators, analysers and impossible to find parts... I guess I'll stick with commercial.

Here, it's 6:50 PM