[R-390] The OLE receiver sensitivity test revisited

[wb5uom at hughes.net]

Good point Curt,
Ive been sitting here pondering your thought.

So, would I use the standard method up to the point of setting the reference 
noise level with the line level meter /adjustment
and THEN use the actual ssb audio signal from then on

OR

Do we care because we KNOWwe are never going to actually hear a -138 
(or -128 ,or -118DBm ) station
because we are not (in normal operating conditions) going to have a noise 
level that low on hf anyway.

(although in years gone by my QTH has has some pretty quiet late nights)

Just a thought.




----- Original Message ----- 
From: "Curt Nixon" <cptcurt at flash.net>
To: <r-390 at mailman.qth.net>
Sent: Tuesday, February 28, 2012 7:59 PM
Subject: Re: [R-390] The OLE receiver sensitivity test revisited


> That is interesting..
>
> I also have a generator that will go down to -138.  I haven't tried it
> but that would be under no noise conditions..only internal noise.  On
> HF, it is my experience that for the most part, we are never limited by
> the sensitivity or the noise floor of the Rx but the level of QRN present.
>
> Curt
> KU8L
>
> On 2/28/2012 8:07 PM, wb5uom at hughes.net wrote:
>>
>>
>>   Ok Now that there are some awake from the PING Test:
>>
>>   I know that there is the 'standard' +30 plus year old method(s) of
>>   measuring receiver sensitivity on the R-390.
>>
>> But, since I took delivery of my AeroFlex 3920 service monitor, 
>> (primarily
>>   for working on P25 digital radios) and after a couple of firmware 
>> upgrades
>>   to get the SSB generate fuction on track with the correct readings, and
>> seeing as how it now goes down to -138DBm, I though I could put it to use 
>> at
>> home as well.
>>
>>   In SSB mode and with a 1000cycle tone, I can hear it all the way down
>> to -138DBm on my
>>   R-390 (I get down to various levels on my other receivers,but not that 
>> far,
>>   which tells me I could copy a CW signal pretty much down in the mud (If 
>> I
>>   had headphones on)
>>
>>   My idea is to make a test tape of sorts into a .wav file on the pc and 
>> play
>> it
>>   back thru the external mod input on the service monitor
>>   to see how far down I can go with VOICE.
>> Actually,I thought about recording an actual broadcast of whatever (AM /
>> SSB )
>> and play that back thru to give me more realism, and crank the level down
>> and see how I can go.
>>
>> What the heck Ive got over $50K in the machine, might as well put it to 
>> use!
>>
>>   Thoughts?
>>
>>   David / WB5UOM
>>
>> ______________________________________________________________
>> R-390 mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/r-390
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:R-390 at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html