[Drakelist] New R4C owner
I am new to this list so please bear with me. I have a pristine-looking R4C S/N 23247 and I'm trying to decide whether its overall gain is up to scratch. The manual doesn't appear to give a specification in terms of how many microvolts at the antenna input for how much audio output or how much input for the onset of AGC or for a given AGC voltage or anything along those lines. It can (just) hear 0.1uV PD on 10M, so the front end seems fine, but that test doesn't say anything about overall gain. I will have some questions about S-meter settings, but I'll leave those for later. Please can you folks give me some idea of how you check overall receiver gain and the sort of results I should expect. 73, Alan G3XAQ -- Alan Ibbetson a...@g3xaq.net ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] New R4C owner
Alan, you could have taken the words out of my mouth. I have been pondering exactly the same question with regard to the RX side of a recently acquired TR4. Anyway, you can be sure of getting an amazing amount of help from the guys on this net and I will look forward to hearing the advice you receive. Nearly 40 years ago I had a R4A. Fabulous receiver. Enjoy your Drake. 73, DamienG3XER Date: Tue, 25 Sep 2012 11:36:09 +0100 From: a...@g3xaq.net To: drakelist@zerobeat.net Subject: [Drakelist] New R4C owner I am new to this list so please bear with me. I have a pristine-looking R4C S/N 23247 and I'm trying to decide whether its overall gain is up to scratch. The manual doesn't appear to give a specification in terms of how many microvolts at the antenna input for how much audio output or how much input for the onset of AGC or for a given AGC voltage or anything along those lines. It can (just) hear 0.1uV PD on 10M, so the front end seems fine, but that test doesn't say anything about overall gain. I will have some questions about S-meter settings, but I'll leave those for later. Please can you folks give me some idea of how you check overall receiver gain and the sort of results I should expect. 73, Alan G3XAQ -- Alan Ibbetson a...@g3xaq.net ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] R4C overall gain specification
I have the data I was seeking on R4C overall gain, thanks to Steve Wedge W1ES/4. The original 1974 QST review gives it as 0.1uV or less for 10dB S+N/N. Although my receiver can detect a 0.1uV signal it's well short of that amount of audio output, so it looks like I have some work to do to find a bit more gain. -- Alan Ibbetson a...@g3xaq.net ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] R4C overall gain specification
- Original Message - From: Alan Ibbetson a...@g3xaq.net To: drakelist@zerobeat.net Sent: Tuesday, September 25, 2012 10:49 AM Subject: [Drakelist] R4C overall gain specification I have the data I was seeking on R4C overall gain, thanks to Steve Wedge W1ES/4. The original 1974 QST review gives it as 0.1uV or less for 10dB S+N/N. Although my receiver can detect a 0.1uV signal it's well short of that amount of audio output, so it looks like I have some work to do to find a bit more gain. -- Alan Ibbetson a...@g3xaq.net Older receiver specs gave a minimum audio output level for a given input level. This is useful for seeing if the receiver is working correctly and is, I think, what you want. The spec as given above does not specify an output level so it really does not indicate gain. Its a typical old style spec for noise level and is again useful for checking a particular kind of receiver for normal function but not much else. The R4C book gives a spec of 0.7 watt of audio at the AVC threshold and a minimum power output of 2 watts at less than 5% THD. You can check the power output using a resistor load and voltmeter but monitor with a scope to keep from going into overload. 5% is just visible. Presumably, the AVC threshold is where the S meter just begins to indicate, or just a bit below that. I would do the S meter adjustment procedure before trying this measurement. If you find the receiver is really not up to snuff its worth going through the entire adjustment procedure. I think Garrey Barrell has a disc for the R4C and it may have stage gain info, contact him about this. He is _not_ on this list. www.k4oah.com -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
