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I Wonder....

Posted: Fri Aug 30, 2019 8:53 pm
by SOTS 87 7
I wonder if this might be ok for medium wave. Just a thought.
HF Amp.jpg

Re: I Wonder....

Posted: Fri Aug 30, 2019 10:56 pm
by Albert H
If it's designed to do "Top Band" - 1.8MHz / 160m, then it should work at the top end of the medium wave.

My very first transmitter was a Practical Wireless 1965 AM 807-based top band job. I put a few more turns on most of the coils, and it went down to the top end of the MW. I had a lot of fun with that rig, connected to an inverted-V aerial and a buried galvanised dustbin for the earth!

Re: I Wonder....

Posted: Sat Aug 31, 2019 12:16 am
by SOTS 87 7
I had a feeling it might, the specs say between 3 - 30Mhz. Seems incredibly wide band to me.
I've got one assembled so maybe I'll give it a try.

Re: I Wonder....

Posted: Sun Sep 01, 2019 12:27 pm
by Albert H
It's a bit high if it's designed for 3MHz upwards. The gain at MW will be much lower, and it might tend to prefer to amplify the harmonics of the driver!

Re: I Wonder....

Posted: Sun Sep 01, 2019 11:05 pm
by SOTS 87 7
Mmm, yes indeed. There doesn't appear to be any kind of filtering on it either which is a tad scary but I'll give it a shot. What's the worst that can happen :lol:

Re: I Wonder....

Posted: Sun Sep 01, 2019 11:21 pm
by Albert H
Are you going to try it as a linear? If you're using low level mod, you might want to consider a bit of envelope feedback to clean up the audio somewhat.

Re: I Wonder....

Posted: Mon Sep 02, 2019 7:07 pm
by SOTS 87 7
The intentions were to, yes. But now you come to mention it I seem to remember from the days of AM CB radio the audio always seemed to get more scruffy the more power you put out.
Thanks for the advice Albert, I will give that a go.