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Re: [TenTec] 2nd Try: SDR Technology ?

To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
Subject: Re: [TenTec] 2nd Try: SDR Technology ?
From: "Rick - DJ0IP / NJ0IP" <Rick@DJ0IP.de>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Sun, 28 Dec 2014 14:02:07 +0100
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
Eric,

It makes no difference what country you order from.
It's the same procedure for all countries.
You see the shipping cost when you check out.

James, K8JHR ordered one from FunkAmateur and had no problems.
FunkAmateur in DL is kinda like CQ Magazine in the states.
It is the second largest ham radio magazine.
They publish lots of projects for people to build and if there is enough
interest, they offer kits for them.
Here is a direct link to where you order them:
http://www.box73.de/product_info.php?products_id=3081 

It looks like International shipping is just 5.90 Euros (about $8).

It is a kit but all of the SMD components are pre-soldered to the board.
Like most others, they accept credit card or PayPal.

When you try to pay with credit card, if you have never ordered from Germany
before, the transaction will probably not go through.  This is your own
card's anti-fraud software blocking the transaction because it is outside of
your normal purchasing pattern.  No problem, simply call the 800 number on
the back of the card, explain it was you (yourself) trying to make the
purchase, and they will authorize you to do so.   However you will probably
have to enter your order again.

Note: I have no business relationship with FunkAmateur, other than I
subscribe to the magazine.

73 - Rick, DJ0IP
(Nr. Frankfurt am Main)


-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of R. Eric
Sluder via TenTec
Sent: Sunday, December 28, 2014 12:13 AM
To: n4py3@earthlink.net; Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] 2nd Try: SDR Technology ?

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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