I looked the FiFi up and it seems like a nice unit. What I don't see is a way
to order it from the U.S. Bummer...
-Eric
W9WLW
Sent from an iPhone
> On Dec 27, 2014, at 5:17 PM, Carl Moreschi <n4py3@earthlink.net> wrote:
>
> That because as you sample the RF input, the number of bits you have
> determine the maximum range. With 8 bits, you can go to 256. With 24 bits
> you can go to 16,777,216. The ratio of those two is 65536 which is 48 db more.
>
> Yes, the Germain Fifi looks way better than the Watson.
>
> Carl Moreschi N4PY
> 58 Hogwood Rd
> Louisburg, NC 27549
> www.n4py.com
>
>> On 12/27/2014 4:47 PM, Rick - DJ0IP / NJ0IP wrote:
>> I'm going to come back and answer my own question.
>> One of my friends in the BCC just clued me in.
>>
>> I was looking at and comparing the German FiFi with the Portugese (Watson)
>> DX Patrol.
>>
>> The DX Patrol has an RTL2823 Chipset (8-bit), whereas the sound card in the
>> FiFi is 24 bit.
>> This means the FiFi will have a much greater dynamic range.
>> 8-bit is pretty skimpy.
>> In addition, the FiFi comes with a second printed circuit board (piggy back)
>> which is a set of pre-selector filters. This means, in the event I want to
>> use it as a stand-alone receiver (without the BPF from the Eagle), it will
>> be better.
>>
>> Clearly the FiFi is well worth the $45 more that it costs.
>>
>> Apparently you increase the receiver's dynamic range by going to a higher
>> bit-count on the sound card.
>>
>> 73 - Rick, DJ0IP
>> (Nr. Frankfurt am Main)
>>
>>
>> -----Original Message-----
>> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Rick -
>> DJ0IP / NJ0IP
>> Sent: Saturday, December 27, 2014 10:07 PM
>> To: n4py3@earthlink.net; 'Discussion of Ten-Tec Equipment'
>> Subject: Re: [TenTec] 2nd Try: SDR Technology ?
>>
>> Carl,
>>
>> That was beneficial. Tnx.
>> I had seen 96kHz sound cards but didn't realize there were 192kHz sound
>> cards.
>>
>> Isn't there some kind of rule like the radio can display about half the
>> sampling rate, so a 192kHz sound card would display 96kHz. (?)
>>
>> So with these low cost radios, what does one have to look for to get a
>> better BDR3?
>> As I pointed out earlier, the BDR3 is not great with these low cost SDRs.
>> Of course it is fantastic with the direct sampling SDR - but slightly out of
>> my price class. ;-0
>>
>> 73 - Rick, DJ0IP
>> (Nr. Frankfurt am Main)
>>
>>
>> -----Original Message-----
>> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Carl
>> Moreschi
>> Sent: Saturday, December 27, 2014 6:22 PM
>> To: Discussion of Ten-Tec Equipment
>> Subject: Re: [TenTec] 2nd Try: SDR Technology ?
>>
>> Let me take a shot at this.
>>
>> There are basically two types of SDR panadapter receivers.
>>
>> 1) Direct converison receivers. These use the same method as the old Tentec
>> Century 21 and convert RF directly to audio and then digitize it.
>> The audio image is removed by the phasing method like the very old
>> original SSB transmitters. The disadvantage to these radios is you might
>> hear the oscillator running and this might appear on the display.
>> Normally they run the oscillator with a 10 khz offset to get it away form
>> the signal of interest. The other disadvantage of this type of receiver is
>> it will use your sound card. The stock sound card in most computers only
>> allows 48 khz of spectrum. You can get a more expensive sound card to put
>> in your computer that can increase the spectrum to 192 khz. Examples of
>> this type are all the Softrock receives. All the Flex radios prior to the
>> 6000 series use this method.
>>
>> 2) Direct sampling receivers. These radios convert the RF signal at the
>> antenna directly to digital. They do not use your computer sound card.
>> They are normally very sensitive. They usually can display many mhz of
>> spectrum. Examples of these receivers are the Tapr Hermes, Flex 6000
>> series, Elad FDM-S2, Microtelecom Perseus.
>>
>> Clearly the direct sampling receivers are better but they also cost a lot
>> more. And if the direct conversion radios are done correctly, they can also
>> work very well.
>>
>> Carl Moreschi N4PY
>> 58 Hogwood Rd
>> Louisburg, NC 27549
>> www.n4py.com
>>
>>> On 12/27/2014 5:35 AM, Rick - DJ0IP / NJ0IP wrote:
>>> First pass brought a lot of suggestions for SDR models, and I have an
>> exact plan about how I want to attach the receiver to my Eagle, and manage
>> it with N4PY software. I have a short list of 2 receivers. I may possibly
>> be able to borrow a Flex 1500 for a couple of months and use it as a
>> receiver.
>>>
>>> However, my fundamental question did not get answered, in fact not
>>> even
>> really addressed.
>>>
>>> "What technology differences do we compare when evaluating SDR receivers?"
>>> (Let's stick with the low cost - under $300 - for this thread
>>> please.)
>>>
>>> Basically all of the SDR radios are sensitive enough.
>>> I guess, at least for the low cost models, the selectivity is
>>> determined
>> by the sound card.
>>>
>>> I want to compare radios that have built in sound cards because I
>>> don't
>> want lots of wires running to my laptop.
>>> But what do I look at?
>>> Do we compare sound card chips in this case?
>>> If so, what specs of the sound card chip are important?
>>>
>>> What else?
>>>
>>>> From what I have been able to find on the web, all of these low cost
>> models have a close in BDR3 ranging from about 65 to 75dB. Not great but
>> acceptable for daily use, at least in SSB. Better receivers go for $500 or
>> more. No surprises there.
>>>
>>> For my initial project, I will just use some simple stuff, but I'm
>>> curious
>> to learn more about this technology.
>>> It won't be too much longer before the theory we all learned is school
>>> is
>> not even used anymore.
>>>
>>> BTW, this is one of the best pages I have found so far on this topic:
>>> http://www.rtl-sdr.com/roundup-software-defined-radios/
>>>
>>> 73 - Rick, DJ0IP
>>> (Nr. Frankfurt am Main)
>>>
>>>
>>>
>>> _______________________________________________
>>> TenTec mailing list
>>> TenTec@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/tentec
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