How-To 2m and 70cm DEMI Transverters on a 6700 & Questions

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I have researched the forum for Transverter installation options/ideas and there are several threads floating around with information. It is a bit scattered so I thought that I would put my findings and decisions on a new thread that might be helpful to others.

The goal for me is to add the 2m and 70cm capability that I get out of my TS2000 to the Flex 6700. I want to have an all mode HF, VHF, UHF rig capable of working repeaters, SSB DX and SAT (even EME).  

After talking to FRS (Thanks Dudley) and DEMI (Thanks Sandra for your help) I have a better idea on how to proceed. But I would like suggestions or comments if you guys find holes in my current configuration idea.

The 2m part will be covered with the Amp-Preamp DEM 2MLDPA. In my case I went for the 60w version.

http://www.downeastmicrowave.com/product-p/2mldpa-60.htm



I added the following options:
  • LDREM-OPT for remote ON/OFF
  • LD-HP Common RF for a single connection to antenna
  • XVRT IN and XVRT OUT ports (Default)
For the 70cm part I selected the L432-28HP which is the fully assembled 28Mhz IF 60w output 440 Transverter.

http://www.downeastmicrowave.com/product-p/l432-28hp.htm





The image above doesn't have the TX IF and 10 Mhz ref input BNCs.

I wanted to be able to use it with the 6700 and the Flex 1500.
I added the following options:
  • Split IF configuration (this is important for Full Duplex)
  • IF Drive 0 - 100mW
  • HP Common RF Configuration (Single antenna)
  • DUAL LO OPTION: Allows the use of either the internal clock or external 10Mhz source.
  • Optional filters to be able to work at both ends of the band for SAT work and Repeater work.
  • I also went with the larger heatsink. 
I also added a 10Mhz reference HUB. The DEMI 10-4:

http://www.downeastmicrowave.com/product-p/10-4.htm



This is a very interesting device if you happen to have the GPSDO option in your 6700/6500. It allows you to use the 10Mhz reference from the Flex radio and input that into 4 devices. In my case I will use it to send a 10MHz ref to the 70cm transverter, the Flex 1500 and the Kenwood TS2000 with this TXCO replacement (http://www.vk3hz.net/XRef/XRef_Home.html).

Remember to add BNC 50 Ohm 1w  to the unused ports.



Now on to the schematic for the connection with the Flex 6700.



Which finally brings me to my questions and concerns:

  1. I have to share the XVTR port for both 2m and 70cm so, how do I tell from the 6700 to engage TX2 or TX3 based on the panadapter that is TX in SmartSDR? Those are the blue lines on the schematic.
  2. I see how if I TX in 2m I can RX in 70cm because I will TX out of XVTR and RX on RXB on the Flex (green line). But what about TXing in 70cm and receiving in 2m? Do I need another port in the DEMI 2m Amp to send the receive preamped signal into RXA? And if I do that? Where do I put a Magnetic Loop for RX?
  3. Am I missing anything in my configuration? Is this doable? 
  4. I have tested with dummy loads and I can move both the TX and RX frequency in 2m and 70cm while I transmit which should allow me to move to compensate for doppler effect when working SATs, but I can't move both panadapters at the same time... I can't find a way to sync them to move them simultaneously. I guess orbitron/sat32/hrd sat will have to take care of that. 
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EA4GLI - 8P9EH - Salvador

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Justin - KL2D

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OK - I received my 432-28HP transverter and DIPS from DEMI, got everything hooked up and it works as advertised. I can see signals on 70cm and 2M.

I have a question though that I'm hoping someone here can answer, I suspect I have overlooked something simple.

When I transmit on 70cm, the transverter keyes up like it should and the LDPA does not, as it should. But when I key up on 2M, the LDPA keys up like it should but the transverter also keys up. This is of course because I am using a key line out from the back of the 6700 to key the 70cm transverter (TX3), so no matter what slice I key up, the transverter also keys up.

My question is, what is the correct way to key the transverter? Is there a way to assign TX3 to a specific slice, the one I am using for 70cm? Is ther some other way that I should be keying the transverter with this setup using the DEMI/DIPS?

Thanks to anyone who has an answer. :-)

Justin
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W9AT

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Hi Justin,

I waded through this thread <grin> as an investment in education.  And, I appreciate all the the kind efforts of those asking for and offering solutions.  As it seems I may have gotten close to being better informed, I am interested in the disposition of the issue you were having with keying of your transverter at the same time as the LDPA as described above.

Any solution on that front?

Thanks much!

Mark W9AT
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Justin - KL2D

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Hi Mark -

What I ended up doing is using the external TX 3 port on the 6700 to key the 70cm transverter. The LDPA does a great job of either keying or not keying via the USB on the 6700 depending on if you have 2M selected for transmit, and I just have to manually either enable or disable the TX 3 port in the radio settings when I want to transmit on 70cm. Not a huge deal, but not as automatic as I would like.

Overall the DEMI setup for 70cm and 2M is a great way to work sats full duplex. With the right transmit port setup it works flawlessly, and with Macdoppler and DogparkSDR the radio and antenna track the sats automatically. It’s pretty awesome. ;-)

Hope that helps, feel free to let me know if there is any other info I can pass on to help you!

73
Justin
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W9AT

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Thanks much, Justin, for your reply.  If you're game, I have a  couple "bonus round" questions <grin> 

1.  I understand the DIPS solution from DEMI used with the LDPA & 432 transverter requires the transverter to have split IF.  What function does the optional split RF in the transverter provide?  Does it just reduce the need for an additional mast relay if using a mast-mounted LNA?  Other functions beside that?

2.  If I understand correctly, the LDPA without power goes into "bypass"--effectively having the IF bypassing the LDPA for a "downstream" transverter.  With the LDPA, DIPS, and 432 transverter set-up like you have, what cabling/configuration/additional-equipement is involved with adding an additional transverter (for example a 23cm transverter)? 

Thanks again!

73

Mark W9AT
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Justin - KL2D

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Hi Mark - 

I'd love to answer both of those questions, but since I don't have any experience with either one I would just be making stuff up....   ;-)

I would actually reach out to DEMI on both of those. I have had a couple of questions and find that they respond pretty quickly to emails. 

Sorry I don't have more info,

73
Justin
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EA4GLI - 8P9EH - Salvador

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I can answer the 23cm xvtr one.
I have one, and when I use 1.2GHz the 144 amp turns off and the 144 IF BYPASSES the amp and goes into the 1.2ghz transverter. This will allow me to work AO-92 in L mode.

All you need is a coaxial from the 144amp bypass port to the 1.2ghz transverter IF in.

I also use the DEMI 10mhz hub and send a 10mhz reference to the 1.2ghz for extra stability.
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W9AT

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Thanks Justin, you were a big help already.  I have a weekend message sent to DEMI with lots of ordering-related questions.  (I'm interested in learning how many business days it takes for an email reply of answers to a sales-related message.  I am encouraged because of your experience.)

Salvador, thanks for your input.  Do you have the DEMI solution of the LDPA+DIPS+432-transverter with an additional, 23cm transverter?  If so, for clarification, I'm trying to understand to what IF the 23cm transverter is connected?  (the 432 transverter or something else like a transverter switch?)  Am I understanding correctly from your note above that you manually unplug the 432-transverter IF coax and then plug the coax into the 23cm-transverter? 

Whether or not you are manually disconnecting the IF coax from one transverter in order to use another, how does SmartSDR "know" which transverter to key?  Or, is that an operator-driven configuration change every time you change TX band?  (profiles?)

My questions are not meant to imply any comment or judgement, just looking to learn.  I think I might be getting close to have my head wrapped around this subject <grin>.

Again, thank you very much.

Mark W9AT
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EA4GLI - 8P9EH - Salvador

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My 1.2ghz transverter uses a 144 MHz IF
There is bypass port in the demi 2m Amp LDPDA
So when it is turned off you can daisy chain another device. So the 144 IF from the Flex radio goes into the demi 144amp, bypasses it and goes with a short length of coaxial into the 1.2ghz transverter if IN.
I tx the 144amp with the USB cable, the demi uhf transverter with tx2 and the 1.2ghz transverter with tx3. I use tx1 for the hf amp.
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EA4GLI - 8P9EH - Salvador

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I started this thread a while ago to try to understand the best way to work SATELLITES with a Flex 6700 and DEMI gear.

After a long process and a lot of help from the community I have reached a point where I am OK with the final result. I created a hand written diagram which I will try to put into VISIO but I thought that it might help others in their station integration.




I also included HF to get a whole idea of the station.

From Downeast Microwave I bought:

2M LDPA - 144MHz Amplifier (75w)
L432-28HP Transverter (60w)
DIPS (Diplexer/Switch)
10-4 10MHz HUB

As far as options go I went for the FTDI USB controller for the 144 Amp and common TX-RX Antenna port.
I selected wide RX filter on the 432 Transverter to cover from 430 to 450
Common Antenna (RX/TX), Split IF (RX - TX), AplLO board so I can use either the internal TCXO or inject a 10MHz reference from the GPSDO option of the 6700.

The 10-4 10 MHz HUB allows me to send the 10 MHz reference from the 6700 into (L432-28HP, 1.2GHz tranverter and Flex 1500) with a port to spare.

-----------

I use a small Coaxial Relay (AMRA MTI ZR30-5523-00) so that I can use the LOOP feature of the Flex 6700. It is pictured as coaxial relay above. These small relays cannot take much power IN but for RX they are perfect, DC to 26.5GHz, they work with 12v and they are very small. I use the KMTronic Web 8 Port Relay to turn it on and off. In combination with PSTRotator I can have the software read the frequency of the Flex 6700 and automatically decide if that tiny relay needs to be on or off. This is very useful because I can then daisy chain FILTERS for HF. I have a homemade AM Broadcast Filter (MW band), RX Only, that stops all the local AM broadcast signals and considerably reduces noise in HF. By having them in the RX LOOP I do not need to worry about power handling. It will also apply the Filter to any of the 4 HF antennas I use, all I need to do is to enable LOOP A in SmartSDR to ANT1 or ANT2.

------

@Mark, As you can see in the diagram the XVTR from Flex goes as follows:

6700 XVTR > DIPS XVTR > DIPS LDPA OUT > 2M LDPA > BYPASS to > 1.2 GHz transverter IF IN

6700 XVTR > DIPS XVTR > DIPS 28MHz OUT > L432-28HP TX IF 

6700 XVTR > DIPS XVTR > DIPS RX OUT > RX A (144 MHz)

What the DIPS does is when I am TXing 144MHz from 6700 XVTR Port it will send that signal to the 2M LDPA. But when I am RXing 144 it will send that signal to the RX A in the Flex 6700 instead of going back to the XVTR port that way I can TX in 432 (28MHz) and listen in 144 for FULL DUPLEX.
When I TX in 144 the USB port will send a signal to the 2M LDPA through the USB cable and engage the PTT on that amp and it will then send a PTT signal with the RCA cable into the DIPS PTT RCA IN port.

When I am in a frequency that IS NOT 2M 144MHz it will turn OFF the 2MLDPA and the XVTR signal will BYPASS the 2MLDPA and go on to another device. In my case an SG Labs 1.2GHz transverter that takes 144 IF. This is a temporary transverter as I only get 3w out of it. It will eventually get replaced by a DEMI 23cm Transverter.



When you connect the 2M LDPA USB cable into the Flex 6700 is shows up as LDPA Type USB device.
 If you double click that it will provide you with the option to rename it and the most important, to turn ON or OFF the internal Preamp. I have the amp next to the 6700 and not the antenna so the preamp this far from the antenna is counterproductive. It is better OFF than ON most of the time.



It would be great if I could automate the Preamp ON OFF or if I could have a button available in the main SmartSDR screen to turn it ON or OFF without having to go through a bunch of Menus. Maybe in a future version of SmartSDR *wink wink

This is what SMARTSDR looks like for a typical Full Duplex SAT



That signal you see there is CAS-4A Telemetry. it just happened to be going over my QTH when I was putting this text together.

You can see here PSTROTATOR in action as well:




I have a long list of SAT profiles I call upon when a SAT is visible from my QTH.
PSTROTATOR moves the antennas, I have a Yaesu G/5500 and EA4TX ARS-USB controller for that.



PROFILES are very important because they answer your TX (PTT Relay) question.

144 MHz doesn't need to use any of the 3 TX relays from the Flex 6700. In my case (as presented in the diagram) TX1 engages the HF Amp, TX2 the 432 Transverter and TX3 the 1.2GHz Transverter. The DEMI gear has a sequencer, so if i where to add an amp for EME, I will use the DEMI sequencer for PTT Relay of the amp.

BUT there is no easy way to assign TX1, TX2 and TX3. You are left creating Profiles for each case. For each SATELLITE I create a Profile. The profiles have the TX settings. If the SAT uses 145 MHz for TX then the RCA TX 1,2 and 3 and DISABLED. If the SAT uses 435 MHz for UPLOAD then RCA TX2 is enabled.

-----

For HF I have an SPE Expert 1.3k. There are some neat features, very useful in combination with the Flex radio. I am utilizing all RX ports with VHF and UHF so the SO2R port on the SPE Expert amp is very useful here.

When I select INPUT 1  / ANT1 in the Expert AMP it will automatically connect SO2R ANT to INPUT 2.
By connecting INPUT 2 to ANT2 in the Flex 6700 I am making ANT2 of the Flex my 3rd RX antenna. This enables Diversity. I can listen to a 80m signal with both the T2FD and the Magnetic Loop. The SPE Expert is connected to the Flex radio by USB cable which automatically will select the correct TX antenna and power levels. 
The SO2R port in the Expert amp is an RX port, so I don't have to worry about mistakenly applying Watts to the Magnetic loop and blowing the PreAmp.
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W2PP

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OK your diagram was beyond helpful.  I'm going to use a very slightly less complicated setup but basically what you drew.  I just ordered all same stuff you did from DEMI and now Q5 signal.  I have a feeling its going to be a minute or two before I see any of it.  But, they make good stuff and have been around for many many years.  In fact I did business with them way back in the 1980's I think.  

I'll be back with operational questions I am sure when I get closer but wanted to pass along a thanks for the great diagram.

Peter
W2PP
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EA4GLI - 8P9EH - Salvador

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I am sure you will enjoy it. It is quite spectacular to SEE in VHF and beyond. Too bad we cannot open receiver beyond 24,000 on WFM as it is a bit narrow for NOAA reception. I really would love if future versions of SmartSDR look at Sat work and VHF-UHF as there are some usability improvements that will make using the Flex for satellites a better experience.

I am kind of surprise Steve N5AC has not "pushed" for some Sat flavor update of SmartSDR as he designed the AplLO board for the DEMI and worked with them on the DIPS, so I believe he is a Sat operator as well.

Maybe soon....
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W2PP

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Maybe I goofed, I ordered the 1296 with a 28 mhz IF.  Can the LDPA pass 28 mhz through its bypass port?  If so that should solve the problem.
Thanks
Peter
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EA4GLI - 8P9EH - Salvador

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Well, it will not if you are using the DIPS which routes 28MHz and 144MHz through different ports.....
If you are going XVTR out into LDPA and then from BYPASS of LDPA to 1.2GHZ XVRT you should be OK.
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W9AT

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Salvador, thank you very much for the depth and detail of your post!  This exceeded my expectation for help, and I am grateful.

I have a much clearer understanding of what is going on with the signal flow in the equipment and how you are using SmartSDR.

Many thanks.

73

Mark W9AT
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W9AT

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In case anyone was interested, complete answers to questions I sent to Down East Microwave were answered in less than 1/2 business day. 

Mark W9AT
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John - WA7UAR

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Are you willing/able to post their answers to your questions in this thread? So much good information here!
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W9AT

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Hi John,

I can summarize:

If purchasing the 2MLDPA with the optional LDREM-OPT, then the other option of LDPRE-OPT is redundant (unnecessary).

Split RF configuration for RX & TX can enable the use of an rx preamp and/or a tx PA without the extra need for TR relays or a separate feed line from an rx preamp.

With the DIPS arrangement, additional transverters would get their IF through the 2MLDPA.

To utilizes the DIPS, the 432 Transverter needs a split IF configuration.  (split RF only needed per users other requirements, not a requirement for DIPS configuration)

The 2m-70cm configuration with the Flex 6700 which uses the DEMI DIPS product no longer is sourced entirely from Down East Microwave:

- 2MLDPA (DEMI)

- DIPS (DEMI)

- L432-28(Q5 Signal LLC, which now provides the transverter line formerly provided by DEMI)

This is a summary of my understanding.  Of course, any corrections or comments are welcome!

Mark W9AT
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Marc Lalonde

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HI this is how i setup my system  on the 6700 

USB  cable is use as band decoder for  all control relay  ,got small arduino board 
for handel that  and PTT line 

but heart of system is both SPDT  RF relay on VHF and UHF  

when VHF is in use UHF  go into RXA   ,and same for UHF in use VHF go to RXA

in the case we work other band ,both UHF and VHF  go to RXA ! 
seem to never go issue  ,  i change UHF for use 26mhZ IF ,so this way i may operate HF or 1296
and monitor both VHF and UHF 





have redo the system for the coming "soon"  6600  but i keep similar relay scheme
so when a Transverter is not in use IF is redirected to  RXA or RXB port and use slight different IF  26/28/32 MHz  ,have 3 IF  and 2 XVRT port let lot of option ;-)
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W2PP

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I read through this thread, wow, lots of very interesting data.  I have a question, which I will echo from a previous poster.  What is the ultimate goal?

Let me digress for a moment, but this will tie in.

Having nearly 35 yrs of satellite operating experience, but zero with the 6700 i think about the following.

I began using a pair of Kenwoods, the TS 711 and TS 811.  Their was no desensing one from the other.

Now, a poster way back in this thread suggested, and is apparently using Elcraft 2m and 70 cm transverters, basically very similar to the Kenwood duo I mention.  

I would THINK this would be a thousand times easier to setup, purchase.  With multiple xvrter outputs on the 6700 can someone help me understand why this wouldn't be a cost effective solution and technically much easier?

Switching pre amps on both antennas that sense RF should suffice too.

Currently, I use the ICOM 9100 and have no difficulty.  But, using the 6700 with the panadapter and all the other features is intriguing to me.

I'm just looking for the least complex approach.

Regarding Frequency synchronization, either use HRD, or if someone is talented, a plug in for SmarSDR that would track two slices.  

Comments please!!  Correct any misunderstandings I have !!

Peter
W2PP
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W2PP

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PS, I overlooked one obvious problem, with ONE xvrtr in/out full duplex is an issue. 
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Marc Lalonde

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not if you use RXA or RXB as receive port on the receiver XVRT ,see my above diagram

6700 6600 have 2 SCU so full duple by nature 
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W2PP

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Thanks I see that now.  I had forgotten about those two supplemental receive ports.  However, if you want to swap transmission, so as the original poster noted, if instead of 2m up and 436 down, you want 436 up and 2 meter down, you need to reverse these two connections correct?  Your switch above looks like it handles that perfectly.

What switch did you use for RF switching?  Do you have code for the arduino?

Peter
(Edited)
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W2PP

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One more thought on simplifying this.  If you have two xvrtrs with split IF, RX A and RX B could be used permanently for each xvrtr. Then all you have to do is manually switch the xmit IF.  Since this is done fairly infrequently, that is people tend to stay on the same type satellite, you wouldn't even need a switch just manually plug in the appropriate xvrtr to the xvrtr port on the 6700.  Did I over look anything?
Peter
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Marc Lalonde

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yup i may work  ,in case of 6700 it actually 1 XVRT and one 2MLDPA
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Justin - KL2D

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It’s actually pretty easy to use, and once you set it up you never have to switch cables again. You just swap the receive ports on your slices and this is done in the software right in the slice.

Plus, if you use software like Macdoppler it tracks the request of both slices for you. This can probably be done with SatPC too but I have never played with it much.

I agree with Marc, being able to see the signal on the waterfall and make adjustments to sync up with it is great. Now that I am used to “seeing” everything in the spectrum, it’s hard to imagine going back to not having the waterfall.

My setup is one 70cm xvtr, 2MLDPA, and DIPS relay switch all from DEMI. Once it’s all put together it’s transparent to the operator and the 6700 works like a 160-70cm all band all mode radio.

In the end, just a matter of preference I suppose.

73
Justin
KL2D
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Marc Lalonde

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Hi  for me panadapter ,and remote operation ,overcome the transverter setup difficulty
and flex is not harder to setup that any HF radio whit multiple transverter 

it just need some one to have a commercial of the box solution , may a idea for DEMI
i may make one someday ..

if you operate QRO RF sensing is not good you will fry LNA and relay  ,better to use BCD usb cable 

finally if whant only satellite operation the 6600 is for you whit 2 XVRT port so very easy to setup 
for EME or serious VHF+ contesting 6700 is better ,since mutch better dynamic range that a transverter on VHF

Marc  VE2PN