Old veronica transmitter 12w fault

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Albert H
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Re: Old veronica transmitter 12w fault

Post by Albert H » Tue Jul 17, 2018 11:03 am

sinus trouble wrote:
Mon Jul 16, 2018 10:25 pm
Glad you got it going Mr Novaro!

As Albert mentioned, If you have an Original Veronica? I see no reason why you would not use the stereo coder! Excellent quality!
If you are using software? You may aswell just use that to do the limiting too!
Drawmer kit are excellent quality but I think you may struggle to find one in good condition?
My experience with Behringer has been terrible!! Don't waste your money on them cheap things!
The Alesis 3632 is what I currently use and have never had any issues with it so far!
Happy Broadcasting! :)
The Alesis 3632 has some nasty effects due to their choices of cheap components. If you beef up the power supply smoothing capacitors you'll be surprised at the improvement in quality. Also they used 4558 dual op-amps in a couple of the audio stages. These were OK in 1980, but these days I'd change them for something quieter. I like the LM833 or NE5532 - both entirely pin-compatible with the 4558 - and they're now cheap as chips!
"Why is my rig humming?"
"Because it doesn't know the words!"
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Novaro
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Re: Old veronica transmitter 12w fault

Post by Novaro » Wed Jul 18, 2018 8:28 pm

Albert H wrote:
Tue Jul 17, 2018 11:00 am
Novaro wrote:
Sun Jul 15, 2018 1:28 pm
I am posting a useful piece of info I found for the veronica pll3 .
stanpedro diyAudio Member

Join Date: Jun 2014
the TRW PT8860 is a 1.8 watts npn rf transistor at 175MHZ. it is the final out in the veronica 1 watt PLL3 transmitter. the driver for it is the 2N4427; (1 watt at 175MHz) and i think this is what you are looking at. i have one and i can tell you pt8860 is almost impossible to find but there is hope. ECG/NTE 472 (2N5913) and MRF607 are exact replacement fot it. 1.8 watts at 175MHz and all other specs are identical. you can get it on ebay
Wrong! The PT8860 is rated at 11Watts RF out at 400MHz with a 13.8V supply. I have the page of the 1981 TRW specification book open here as I type. I've run these on Band II as both drivers (using them for 8 Watts to drive a pair of BLW60s to about 80 Watts) and as output devices when I've needed 10 Watts in a hurry! They're really ancient devices, and have about 7dB of gain at 400MHz, rising to around 11dB of gain at Band II. This suggests that Paul's 2N4427 should be doing around a Watt to get 12 Watts out of the PA.

The only reason that Paul used these transistors is because they were available on the surplus market for 50p - £1 in the late 80s and early 90s. They're not particularly robust, unless they're really under-run. The SOAR is surprisingly small for a TRW device of that vintage.
I can not disagree with you! Your knowledge is always the most valuable piece of info one can get from the net.

Novaro
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Re: Old veronica transmitter 12w fault

Post by Novaro » Sat Jul 21, 2018 11:26 am

I replaced the cd4016 with cd4066 and the stereo encoder is now improved by much especially on high frequencies. The metallic and harsh highs are now controllable with better definition. If I remember the person wrote the article said the distortion dropped ten times.
I lost the link to the article with the other improvements.

Novaro
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Re: Old veronica transmitter 12w fault

Post by Novaro » Sat Jul 21, 2018 11:34 am

Setting the modulation using the stereo indicator of a grundig receiver.
Using a screwdriver I turn the modulation of veronica pll to zero position. Then I turn to the right until the stereo indicator of the receiver turns on. The indicator lights when the pilot tone is about 4khz. Then I moving up a little bit more.
Is that procedure correct?
I am getting interesting sound without any processor just the stereo encoder and pll unit. No distortion no fattening of voices or flattened bass lines. A little silent compared to other stations but clear like water of Antarctica.
I really recommend the stereo encoder mod with the cd4066.

radium98
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Re: Old veronica transmitter 12w fault

Post by radium98 » Sun Jul 22, 2018 7:18 am

stereo .?
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Re: Old veronica transmitter 12w fault

Post by Novaro » Sun Jul 22, 2018 10:46 am

radium98 wrote:
Sun Jul 22, 2018 7:18 am
stereo .?
Nice kit. I love these projects. I wish I could do myself.
The mod I have mentioned is for veronica stereo encoder.

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Re: Old veronica transmitter 12w fault

Post by Novaro » Sun Jul 22, 2018 10:53 am

radium98 wrote:
Mon Jul 16, 2018 9:39 pm
use c1947 4w at 175 mhz
Thanks!
Just got one from ebay!

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Re: Old veronica transmitter 12w fault

Post by Novaro » Sun Jul 22, 2018 11:09 am

sinus trouble wrote:
Mon Jul 16, 2018 10:25 pm
Glad you got it going Mr Novaro!

As Albert mentioned, If you have an Original Veronica? I see no reason why you would not use the stereo coder! Excellent quality!
If you are using software? You may aswell just use that to do the limiting too!
Drawmer kit are excellent quality but I think you may struggle to find one in good condition?
My experience with Behringer has been terrible!! Don't waste your money on them cheap things!
The Alesis 3632 is what I currently use and have never had any issues with it so far!
Happy Broadcasting! :)
Hi ,
Thanks!
Yes I have an original stereo unit 12w. I got it new in original packaging for a good price. It's very piece of technology. Seems very professional build.
The encoder mod made it better in my opinion.
As for behringer mdx2600 I heard so many using it in a commercial like setups a decade ago.
I have two fm systems alc771 I bought very cheap for agc. I got finaly an mdx2600 to work after these unit mild compression and limiting. Also the enhancer function will give me a way to brighten a little the sound if needed.
I know that the job is done with pre emphasis in mind the right way but I find the setup I described will fill my needs.
Now waiting for the behringer to arrive from uk!

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Re: Old veronica transmitter 12w fault

Post by radium98 » Fri Jul 27, 2018 2:59 pm

Novaro the one i have posted above is the veronica stereo encoder with very good clean sound in my opinion

Novaro
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Re: Old veronica transmitter 12w fault

Post by Novaro » Sat Jul 28, 2018 6:44 pm

All vintage all nice!!!!
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radium98
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Re: Old veronica transmitter 12w fault

Post by radium98 » Sat Jul 28, 2018 8:06 pm

Can you please shoot a deatailed pictures of the veronica box for every parts etc ...thanks

Novaro
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Re: Old veronica transmitter 12w fault

Post by Novaro » Sun Jul 29, 2018 5:19 am

radium98 wrote:
Sat Jul 28, 2018 8:06 pm
Can you please shoot a deatailed pictures of the veronica box for every parts etc ...thanks
Yes sure I can. I will during the day.

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Re: Old veronica transmitter 12w pictures

Post by Novaro » Sun Jul 29, 2018 7:54 am

Veronica pll3 pictures
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radium98
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Re: Old veronica transmitter 12w fault

Post by radium98 » Sun Jul 29, 2018 7:55 am

nice thanks

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Re: Old veronica transmitter 12w fault

Post by Novaro » Sun Aug 19, 2018 12:11 pm

I am stopping broadcasting once again. I have not managed to have a good sound with any tools I tried.
There are so many parameters to achieve a good sound loud but not flat and muddy.
Agc - limiters - pre emphasis clipper and their distortion.
I understand that the sound have to be over a noise floor to sound natural for ears. Under that you have to concetrate on that.

I have five setups. None of them gives a good sound!
1) Just with veronica stereo coder. Sound acceptable. Good transients give a dynamic sound not loud but almost listenable. Unknown levels for good deviation. I don't have a measuring device to setup input vco level.
2) With Behringer composer. Threshold -10 ratio 4:1 auto attack, knee. Output set to -18 to -12 because the is the pre emphasis after inside the stereo encoder. Almost listenable but not radio sound! It's more a protection to listeners ears. Seems that pll is not oversaturated.
3) With a stereo encoder which have a limiter based on bh1417f popular on ebay. Sound is more controlled highs are more pleasant. But not really radio sound.
4) with all the tools you can imagine inside a PC. Not the sound I like. The only I like a little is fm radio preset with Sonos limit. A very old software. Stereo tool gives a sound out of my interest. Maybe I have digital clipping because of my hd realtek standard card? I like audio to be processed but in a transparent way.
5) with alc771 agc units. Without pre emphasis following I get an interesting sound. But stereo coder pre emphasis ruin it maybe because of overshoots of high freq content.

Also tried combinations of the above!
I knew it was difficult to setup sound but I did n't know it was nightmare.

Even levels from one unit to another. Sensitivities, impedance etc have to play a role.
No hope here!

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Re: Old veronica transmitter 12w fault

Post by MC Spanner » Mon Aug 20, 2018 1:58 am

Novaro wrote:
Sun Aug 19, 2018 12:11 pm
I knew it was difficult to setup sound but I did n't know it was nightmare.
I kind of know what you mean, but it's subjective! Can you give an example of who you're trying to sound like?

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Re: Old veronica transmitter 12w fault

Post by Novaro » Tue Aug 21, 2018 11:20 am

Thanks for replying my post.
I am reading now to solve at first technical deficiencies then dive into the art of sounding discussion.
As I told you the most common setup for me is to use my sound card output to feed the veronica stereo encoder. The encoder needs 0db input I think the card has it so the sound is OK for a hobbyist :).

I have heard about setting modulation by ear. Can anybody explain us this technique?

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Re: Old veronica transmitter 12w fault

Post by Novaro » Tue Aug 21, 2018 11:30 am

I forgot to say I am reading about output and input levels impedances highz ,lowz ,db, vrms, etc. I believe part of my problems has to do with energy going from device to device. I think i must have enough energy hitting the input of transmitter then set the modulation. By doing that we are going far the noise floor so louder and more clear.
Some have radios with s/n measurement. Maybe that helps because are cheap instead of a modulation monitor.

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Re: Old veronica transmitter 12w fault

Post by MC Spanner » Tue Aug 21, 2018 11:55 pm

Novaro wrote:
Tue Aug 21, 2018 11:20 am
I have heard about setting modulation by ear. Can anybody explain us this technique?
Without a limiter, you're on to a non-starter unfortunately. You could probably adjust your setup so that one particular type of content doesn't cause over deviation but that almost certainly doesn't mean that other content won't. Do a Google on free audio compressor / limiters, pretty sure there's stuff out there you could use to ensure your soundcard produces something vaguely well behaved. There was one with a VST architecture but I can't remember what it was now, I've just done a quick search and "Reacomp" looks familiar.

So. If you've no test gear, then once you've got a limiter in place and you know it's keeping your levels in check, drive it into persistent hard limiting and adjust the soundcard master until you sound as loud as the nastiest radio station out there without distorting (if that's possible), then back it off slightly. I completely dissociate myself from this method though - you shouldn't rely on this if you want to broadcast. :whistle

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Re: Old veronica transmitter 12w fault

Post by Albert H » Wed Aug 22, 2018 12:11 am

I put a really nice, simple stereo limiter circuit on this board a couple of years ago. It uses an LM13700 and a few op-amps. It's simple, reasonably low noise and low distortion, but very effective.

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