Flex 6500 vs 6700 for casual ham, occasional contester, but fanatic hardware hacker in an urban location

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Hello Everyone- I am considering either a Flex 6500 or a 6700 to augment my Icom IC-9100. I bought the Icom after a long hiatus from ham radio, mostly as a way to tinker with satellite and VHF/UHF modes (maybe EME soon too if I can avoid annoying the neighbors). I've read through a lot of posts here, as well as reviews on eHam (gee some people are just hard to please) and elsewhere, and think the 6500 would be more than adequate. But if I may, please indulge me and let me float my thoughts.

I am attracted to the Flex series by the "God's Eye View" ability to monitor large portions of bandwidth at a time, while possibly operating casually from other areas of my home. I'm in an urban area (inner suburb), so my antenna collection for HF won't exceed a few random wires or dipoles or something similar, plus it can be noisy here. For operating modes I prefer CW, generally QRP to be nice to the neighbors.

I consider myself more a hardware hacker than a ham. I'm an engineer by training (robotics and chip design). I'm the type of person who would attach a photodiode to the input of the Flex, and an LED with matching network to the output of the Icom, just to see what happens. :) That said, I do like the occasional contest, and I am the type of person who would have the radio on in the background in case I want a break from my regular routine. For contesting- the ARRL 10m contest in December is a good model- I'd probably use the Flex for "situation awareness" and then transmit either from that or from the Icom.

I see the main differences between the 6500 and the 6700 being the second SCU, the multi-stage pre-amp, the capability for antenna diversity, and the more stable oscillator. Regarding the SCU- I don't think I'd need the antenna diversity function or would feel the need to monitor the entire HF spectrum at once (as cool as it would be). As for the pre-amp- Given the noise here I don't think the last few dB would matter. (And if I really wanted I could always just get a preamp.) As for the oscillator- if I were doing something that needed the ultimate stability I'd just get the GPSDO. So it would seem the '6500 would be quite adequate, actually much much more than adequate given some of the fantastic results more serious contest enthusiasts have reported here.

All that said, is there anything I may be missing? (Apologies if I'm coming across as the guy on the car forums asking whether or not to buy the "S" version... :) )

Thanks in advance,

Geof
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AA3RQ-Geof

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Posted 4 years ago

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Jon - KF2E

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Based on what you describe as your normal operation and environment you might want to start with a 1500. It is how I got started with Flex. You can pick one up used for $500 and sell it for the same. It won't display nearly as much spectrum but is still a neat radio. Also, since you say you are in a noisy environment you will be much happier with noise blanker and DSP in PowerSDR. They are light years superior to those in SSDR.

Don't get me wrong, I'm a 6500 owner and very happy. I'm just saying that a 6500/6700 is a big chunk of change based on your operating conditions. If money is no object, go for it. If you want to get into SDR more slowly, start with a 1500.

Jon...kf2e
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Ned K1NJ

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Geof,

    I agree with Jon.  While I have high hopes about the noise blanker improving,
at the moment, PSDR (1500, 3000) does significantly better.  The cw at a given
power level won't be heard by the station you are working any better with any of
these radios.  If this will be your first SDR experience, you are in for a real treat
no matter which you choose.  I happen to think that the 3000 is one of the best
buys in ham radio today.  I have the 5000 and a 6500.  The biggest advantage
the 6500/6700 has is the superb filters.  PSDR  is not far behind, however,
still very good, but the PSDR NB is ahead of the 6000 and most radios on the market today.
    Now, just a little off-topic perhaps.  We just took a near-miss lightning strike.
The whole house, computers, radios, etc. were line surge protected.
The LAN wire apparently not so much.  All devices on the LAN survived,
including the Flex 6500.  It was plugged into the same LAN switch as the PC
that runs it.  The cable modem, a couple of switches, and a wireless access
point were fine, but the on-board network interfaces in two PC's were zapped.
This left me out of the radio business until I could fix it.  The 5000 with its semi-
notorious, but reliable, firewire was still available.  Have a back up.  I haven't
added this up, but it may well be that you could get a 3000 and a 6500 for
around the same price as a 6700. 
     The big spectrum view is nice, but it's not as useful as you might think.
Slices to monitor more than one band is very cool, but if you have a broad-
band or multi-band antenna, you will find in most cases, one antenna port
will be fine.  In my case, I can do that- except for 6 meters.  But, even while
connected to a very poor 6m antenna, I can tell if the band is coming alive
or not.  Then I can change antennas and get into the opening.

  Good luck.  It would be hard to make a really bad choice. They're all great
radios, with a huge fun-factor.

Ned,  K1NJ
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AA3RQ-Geof

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Jon, Ned- These are good comments. I actually thought about the 1500 as a first foray but decided that I preferred the idea of direct sampling and having the "black box" do all the heavy lifting vs. having a host PC process I&Q data. Ned- yes I'm in for a treat...
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Andrew Russell

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Geof,

I am in a similar situation. Started SDR with a 1500 as soon as available. Just had to have a 6500 with GPSDO ASAP and then upgrade the PC. The 1500 mostly is on digital and 630m these days. Its happy on an older dual core win7 PC. The 6500 is amazing, still just having fun with it on phone and HF digital. It is a great RX that I can just listen to for hours. My only concern is that  dual SCU diversity RX will one day be a killer app.

The PC for SSDR does need a bit of 2D graphics grunt, Unfortunately for me the virtual comports and sound cards for PSDR and SSDR don't play nice together.

Don't be too mean and get the best that you can afford.

Andrew de VK5CV

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AA3RQ-Geof

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Andrew- Thank You for the comment on the quality of the RX signal. A lot of reviews (elsewhere) praising the likes of IC-7700, IC-7800, and TS-990S talk about lack of listener fatigue. It is interesting you mention that for the '6500.
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KY6LA - Howard, Elmer

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Yes the listener fatigue in advanced Legacy radios like the IC-7700 is better than old legacy radios

However modern third generation SDR's are significantly better.

We did a/b tests with a 7700 vs 6700. The 6700 was significantly better.
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Scott AC8DE

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Geoff,

First, you need to know that the 6500 DOES have multistage preamps as well.  It just lacks one additional step that the 6700 has; the +30 db step.  (The 6500 stops at +20)  And frankly, since you are in an urban area, your noise level will preclude it making any real difference anyway.  Even the 6300 has preamplifiers, just a step below the 6500, but the 6300 lacks the attenuator step.  The 6300 lacks the preselectors.

The oscillator stability difference between the 6500 and the 6700 is more of a lab measurement and really only means something to guys who working VHF than it means something for a HF guy.  The 6500 is pretty tight.

As you already know, it comes down to the dual SCU's.  In an urban environment, the diversity could be a big difference for you, assuming you can get your two receiving antennas far enough apart.  The other thing is the ability to "listen" simultaneously with two different antennas.  But since you already have a second rig, that isn't an issue, unless you want to listen to multiple bands on 2 antennas.

As an owner of a 6500, I'm pretty happy.  There are a few times I would like the second SCU, but for me, not enough occasion that I would part myself from another $3K.  But if you have plenty of money, why not just go all the way?

In the end, I guess it just comes down to the depth of your wallet.

Good luck on the decision.
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Ken - NM9P, Elmer

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Another difference with 2 SCU's on the 6700 is the ability to listen to two different bands with two different antennas at the same time. I.e. Listen to 6 meters with high preamp in one receiver SCU and 160 Meters with attenuator activated in the other. The 6500 can't do that. I have a 6500 and would LOVE a 6700, but couldn't swing the extra $$$!
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AA3RQ-Geof

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Scott- Thanks for the clarification.Yes the 6500 has a preamp, just not as extensive as the 6700, and I saw the last 10dB as not that critical. (With my IC-9100 all the preamp does is make noise louder.) Is "diversity" *really* that much of a factor? I'm just trying to understand.

Ken- I didn't think about that combination. Thank You.
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KY6LA - Howard, Elmer

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A 6700 gives you the ability to work 8 receivers at the same time....

I regularly use 4-6 for digital and other modes

I would not waste your time or money on last generation technology like a 1500 - anyways its only 5W so virtually useless without an amp...

I also would not get too excited about the NR failings... its software and should be fixed sooner rather than later

I am an inveterate hardware hacker myself...

I am constantly designing and building Bleeding Edge Technology stuff... I even made a pretty good living doing that before I went on permanent vacation...

There is no way I would be happy playing with anything that was not the best, latest and greatest... and I definitely would be bored with Last Generation Technology

If you want to push the envelope buy a 6700...
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AA3RQ-Geof

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Interesting your comment on last generation tech- I was also looking at the IC-7700 and the TS-990S before coming across reviews for Flex. The TS-990S is undoubtedly a fine rig, and for sure my brain would be bathing in dopamine for the week after I bought one, but I cannot let loose the idea that it is a swan-song for a closing era...
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KY6LA - Howard, Elmer

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Geoff

Legacy radios like the IC-7700 and the TS-990 are more than 2 generations out of date. The true swan song of Legacy Radios is the $20,000 Hiberling which shows how much it costs to push the. Legacy Radio to perform near a modern 3rd Generation SDR like the 6700.

Several months ago Rob WA3IHV ran a A/B test with his IC-7700 vs his 6700 on JT-65
The best decode on his 7700 was -19dB while his 6700 was consistently getting decodes down to -26 DB That says it all about how far behind Legacy radios have fallen.

These is a discussion of Modern vs Legacy Radios in my presentation on "How to,Build a Quiet Station

https://www.dropbox.com/s/kffp92esffo...

As I said, as a fellow hardware hacker, i would not be happy with anything but the latest and greatest.
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AA3RQ-Geof

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Thank You for the link to the presentation. I wouldn't have thought of power line noise as an issue but it makes sense. (That comes up in the world of high end audio as well- go figure.)
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Stan - VA7NF

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I'm a 6700 owner to replace the DX-100 I scrapped 30 years ago.  (Silent during and missed the transceiver generation).

In the urban environment the receiver is key, but for neighbor relations, a very clean transmitter is significant (Any 6000 handles that).

Agree with earlier posts that the noise suppression is currently trying to catch up to the PSDR versions and diversity (6700 only) is currently "between the ears diversity"; both of which are getting better. 

A Pixel RX antenna is great, especially when you can't put a beam up 100 feet.  It does reduce the locally generated noise.

Separate concurrent antenna selection is great.  For example my 6700 + Pixel + 6M/2M beam + DEMI 2m amp + 6/2 diplexer was a practical hit on FD 2014.  Monitored 4 HF bands + 6M + 2M concurrently and transmitted with 100W on 6 and 75W on 2.  Pixel on RX-Ant to SCU 1, 6M on Ant 2 with diplexer also on 2M DEMI RF Out connected to XVTR port. 

For (future) full diversity you will need two different types of RX antenna, unless you have acres to separate dipoles.  Only time will tell if the Pixel and dipole will work together and give me better than 1S unit noise reduction.

Again, even with the extra cost in the equation, the 6700 was/is my choice, especially in the inner urban environment.

Note on the DEMI 2M amp - it includes a very low noise figure pre-amp, when coupled with the 6700 pre-amp is hard to beat. I haven't gone above 2M at this time.

73, Stan Williams VA7NF

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AA3RQ-Geof

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Stan- Thank You for pointing me to the Pixel loop antenna- I didn't know about that one. My home is free-standing on a 6000 sq-ft lot so I've some room, more than an inner city town house or condo, but not a lot more. No HOA here. As for neighbor relations- I didn't think about the clean TX of 6x00 as a factor, but yes point well understood.

If I may ask, for your Field Day and related experiences, how much of the benefit of the 6700 was due to monitoring many band simultaneously vs. being able to concurrently use varied antenna types?
(Edited)
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Stan - VA7NF

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Geof,

On FD 2014 I was shy of putting the Flex as a "contest station" and wanted to introduce the idea slowly to the rest of the club.  VE7SAR took Canadian 3A in 2013 so wasn't ready to experiment with this new rig.

Instead the flex took over the station manager position where real propagation monitoring took over from theoretical forecasting.  Since it was a 6700 it could concurrently act as a monitor station as well as a 6M and 2M "free" station; but due to ANT2 and XVTR switching could not be on both 6 & 2 concurrently.

The WOW factor was significant with 6 bands up on a 40" TV monitor, and the (Pheonix?) club with 3 stations on the same band will probably open the door for the flex to be one of the contest stations next year.  Phase noise is significant, in its lack thereof, when you want 2 or 3 up on a single band.  It may augment/replace a K3 as a prime contest station.

The Pixel was the HF all band RX antenna (NOT on Ant1 but on the RX only antenna port).  I remember numerous cases where an operator was looking for a free frequency to "run" and a visual inspection of the full band could find a hole in seconds.  Visiting officials had a conversation starter and could see high technology in what was (previously) considered an old school hobby. 

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AA3RQ-Geof

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Stan- Thank You for the explanation. This is helpful.
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AA3RQ-Geof

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Everyone- Thank You- I REALLY appreciate all the answers here and read every one several times. I feel like I am joining a community here...
(Edited)
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George Molnar, KF2T, Elmer

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Welcome, Geoff. You'll no doubt enjoy operating any of these fine rigs. I too started down the SDR road withh a 1500. So impressed by it I pre-ordered a 6500 and use it every day. Thanks to Flex, I'm more active and excited about ham radio than I have been in 30 years. Sometimes wish I had sprung for the 6700 and the dual antenna receive it offers, but honestly, for me, that wasn't worth the extra cost. For some, it's important, though. My 6500 has really taught me a lot about station design, by the way. The features and quality of the unit have opened my eyes to so much more on the radio spectrum, too.
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AA3RQ-Geof

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Thank You for your post.  This only makes me more eager to get started...
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AA3RQ-Geof

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Thanks again everyone. I just pulled the trigger on a 6500. I figure I can always upgrade at a later time if I really want the second SCU.
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Ken - NM9P, Elmer

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Excellent! Once you have tried the 6000 Series, you will never go back to Legacy radios. I highly recommend that you also spring for the FlexControl Knob. Opinions vary on this addition, but I have found it invaluable to my operating style.

Then, once you have the rig, you will be looking for a quality mike. Then....... It is a never ending process! Ha.

Welcome to the Flex Family! Take your time and read the instructions, search the forum, and ask questions. Ham radio is getting ready to take a major turn towards "fun" for you.
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AA3RQ-Geof

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Thanks! Yes- I did get the FlexControl knob. I'm really looking forward to this.
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Stan - VA7NF

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Looking out even further with diversity and GPS high resolution time, a bank of 6700Rs remoted on a receiving antenna farm, MAY be able to supply the second signal for "ultimate?" diversity reception.