EMRFD Message Archive 12523

Message Date From Subject
12523 2016-03-21 15:56:37 kg4rll@yahoo.com Re: [emrfd] Receiver gain pot question
Hi Craig,
Try it out and see if it will work.
Probably will but the control will be more sensitive to changes, touchy if you will....
Good luck experimenting

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12524 2016-03-22 10:27:24 motherlessgoose Re: Receiver gain pot question
I can see that the pot is essentially a voltage divider, so from that perspective it may not matter.  But making it 10k would limit the current more.  I don't think the circuit is looking for current at that point.

One thing I was thinking is I could just put a 1k resistor in parallel with the 10k pot to simulate the 1k pot...it just would not be very linear.  So maybe I'll try the 10k by itself and then put in a 1k if there are issues.

I chose that project in the book to train myself in the art of ugly construction.  This is my first ugly construction project :-)
12532 2016-03-22 19:56:50 iam74@rocketmail.... Re: Receiver gain pot question
Probably the simplest soluti
12533 2016-03-22 20:17:36 kerrypwr Re: Receiver gain pot question
Here's an interesting article on "tailoring" pots with external resistors;


Kerry VK2TIL.
12535 2016-03-23 08:47:11 cwfingertalker Re: Receiver gain pot question

I have a simple receiver that had the same RF pot feature.  I found my pot was too noisy every time I turned it.  I wound up building a 10db attenuation pad.  That works fine.  You need it on very strong stations to knock down the signal so it does not overload the front end. Just switch it in and out.

I also thought about using a PIN diode so you could vary the attenuation but by then I was making a "simple" receiver more complicated.  


Bill N7EU
12648 2016-04-13 11:32:54 kb9fko Re: Receiver gain pot question
Definitely worth doing the ugly construction.  When I first did it, I was impressed at how fast the construction was.  And it was suprisingly easy to modify and hack, more so than I would have imagined.

Best regards,