[TenTec] 2nd Try: SDR Technology ?

Sun Dec 28 13:16:20 EST 2014

I ordered it and it works pretty well.   I offered to send mine to Rick 
to play with ... but if he does not take me up on the offer, then 
someone else could purchase it from me.

I went to the LP-Pan2 with N4PY and various software options on my Brand 
X radio with its own 9 MHz output.  Works swell, better with N4PY than 
LPB2 - at least in my station.

Just MY take.

Rick... you wanna borrow my FiFi ?  If not, maybe someone wants to buy 
it for cheap?

---------------------- K8JHR  ----------------------------

On 12/27/2014 6:12 PM, R. Eric Sluder via TenTec wrote:
> 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 at 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 at contesting.com] On Behalf Of Rick -
>>> DJ0IP / NJ0IP
>>> Sent: Saturday, December 27, 2014 10:07 PM
>>> To: n4py3 at 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 at 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)
>>>>
>>>>
>>>>
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