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Someone had Corsair II AM TX experience?

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Zazzle:
Hi,


--- Quote from: Pigmeat on January 09, 2017, 0743 UTC ---(...) walk in to your tx site in temps well below freezing, be tuned up and ready to go and have one of the things fry on you.

--- End quote ---

Aren't we here for the adventure? At least a little bit? :)
And well, what pisses us off today becomes a funny story to share in a few years.

But yeah, I feel with you. I had it in Summer 2016. Just the other way around. I was installing the setup for the 30W Beacon. In a night with 36°C. On a black tar roof - all hot from the day - doing acrobatics. Eventually, after hours of sweating, everything was in place. I plugged the PSU in and.... dead. It had been working 5 minutes before. I literally kicked that damn Toshiba Notebook PSU from the roof and half across the complex yard.

I guess it's what brings the fun. Having a small adeventure during night hours. Collecting memories. :)

Kind greetings,
Zazzle.

Pigmeat:
Walking up on bears coming the other way, but that's another story.

netsmo62:
In the end altough I have made so much tweakening and modification, modulation quality was not better than average-mediocre. So I have decided to change completely the modulation type from "low level" to a more classic "high level" directly on the final mosfet, using a simple serial modulator built between a little SMD TDA2030 AF Module (you find very easily on Ebay or Ali or Bang for pennies, like this: http://www.ebay.it/itm/TDA2030A-Audio-Amplificatore-18W-6-12V-Amplifier-Arduino-Module-Board-/252397102253?hash=item3ac40a24ad:g:9lMAAOSwq5pXP19y) and a good 2N3055 TO-3 transistor with a radiator. This was taken out from the open source book "Low Power AM Handbook". This design involving you raise the power supply for TDA2030 AF module, 2N3055 transistor and RF final IRF530N mosfet to 24V and almost 3A, so you need to put a 7812 linear regulator (with radiator too) to supply DDS module, BF245 and BS170 stage. Now modulation is very clear and somewhat more RF power out! To adapt a normal potentiometer to AF module I have literally cut out its 10K trimmer leaving some mm of old connectors to solder up new connection for the new 47 Kohm linear panel potentiometer.

Hi F.

radiorob:
i know it is an out topic yes,
I'll tell you anyway I will try this too!
if only looking for fun with a TDA2030 and also with the TDA2050.
I'm going to try it on SW and on MW
I accidentally got some Darlington transistors RCA9228D to see what you can bake with that!
 ;)
greetings from the Netherlands!
RadioRob

Intruder:
Sorry to resurrect a old thread!

A few years ago I had a Dave Martin built Corsair that I purchased off someone from Facebook and remember it having poor audio, I don't know if the guy I bought it from had played around with the insides but it sounded distorted on air so I sold it on!

Recently I came across some pictures I took of the insides of the one a sold and seeing a post on another forum of someone who recently built one I decided to order the bits and reproduce my own.

I built the experimental gate modulated version to roughly the same size and layout as Dave's versions with images I had and found on the other forum. This did have the same issue with distorted audio and they only way I could improve it slighty was putting a 10nf capacitor across the 1uf capacitor but wasn't great.

Today I finished a 2nd version of the experimental gate modulated version but the layout is completely different and I can say it noticeably better with no distortion to the ear that I hear.

So can confirm the experimental version works ok  :)

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