TX freq response of Flex 3000 & 5000 compared

[w1vtp]

All

I lifted this off the Flex-Radio site.  There's been a bit of talk about the difference between the 3000 and the 5000 TX freq response.

Summary:

• 3000 AM - DSB freq resp = 10 Hz - 7,500 Hz
• 5000 AM - DSB freq resp = 10 Hz - 20,000 Hz

I've included a PDF of the pertinent information.  PowerSDR includes a 10 band EQ that works fairly well.

Al

[flintstone mop]

Both look very respectable.

Fred

[WA1GFZ]

3000 has a cheaper audio interface

[N2DTS]

We have hashed this out on the air many times.
Flex chose to limit the flex 3000 TX to 3750Hz audio in AM, 7500 Hz TX bandwidth.
(3750 each side of carrier).
Since the receive goes out to the usual 20,000 Hz, flex just decided to limit the TX bandwidth.
Its not a hardware limitation.
I don't buy its any kind of marketing ploy, as the 5000 has a LOT of stuff the 3000 does not, 3 antenna inputs, second receiver (diversity, noise null) the ability to fit various power level vhf/uhf modules, better spec's all around.

Jay runs a 3000, and does not sound bad to me, but I have no high end hearing.
Eric always tells me to set mine at 5000 Hz, which seems wide to me (with my hearing) at 10Kc wide signal...

I think flex just decided to limit the high frequencys to prevent complaints from the FCC or ARRL, or something.

I have been waiting for flex to restrict the 5000's, hope they don't do that with the new version coming out sometime this year (maybe).
You can always run the older versions, but if they come out with some 'WOW' features, it might be tough to choose....

Where are all the hacker geeks when you need them.....

On the other hand, I wish some of the class E guys would be limited, I see over 20 Kc wide signals on in prime time, taking everything between 3870 and 3890....


Brett

 

[w3jn]

I can definitely tell the difference between Jay's Ranger and the Flex in the afternoon when I can open up the RX.  Of course under battle mode, with the RXer in 3.2 KC mode, obviously not.

[W1AEX]

Yes indeed. This topic got very nasty in the "official" Flex forum last year. The Flex reps would not divulge who made the decision to bandwidth limit the 3000 and 1500, or why. There was a lot of speculation that it may have had something to do with bandwidth compliance in several markets overseas. They would also not discuss where the limitation was imposed, but most believe that it's in the firmware. As Brett implied, someone with coding experience would most likely be able to compile a bootleg firmware, similar to what is seen with various motherboards that are the favorites of overclockers. I don't believe that Flex would take kindly to that. In fact, I believe that unlike their open source software, they might even have a EULA that prohibits backward engineering their firmware. The discussion in that forum became so nasty, that much of the thread was simply deleted by the forum admins. The bandwidth conservation police were quite angry, and after venting in a quite nasty way, they vowed to write the F.C.C. to demand that bandwidth limitations be imposed on all amateurs to stop all this "wasteful spectrum nonsense". Ah well...

[WA1GFZ]

the 3000 only samples at 44 KHz unlike the 5000 running at 192 KHz. It is all in the software since 44 KHz should go higher than 5 KHz.
Flex has very little interest in anything more than basic AM. Their real interest is the mil market.
The only difference between a softrock and a flex is they use a double balanced tayloe rather than single balanced. Performance gain is very slight.
I wonder when they will step up to the next generation. I suppose they need to unload all the 5000s first.