Flex Suggestion and SO2R support

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Hello all. I have two questions that I'm hoping some people can shed some light on. I'm new to Flex and SO2R so I'm sure these are pretty basic questions to others. :)

1. I currently have a NA4RR Hex Beam antenna. One feed line does 20-6m while there is another that goes to a 40m dipole that is the top wire on the hex. So I guess it's two antenna on one frame. I have been looking at the flex 6400 and 6600 for a while. Would it be worthwhile to go with the 6600 with only having the Hex Beam or would I be missing out on utilizing many of it's features due to my current antenna setup and it would be okay to go with the 6400? My main focus is contesting.

2.  If I went with the 6600, could I do SO2R? If I had a 40m and a 20m band pass filter, could I do SO2R with my antenna or are the wires too close to each other to even have a chance of not blowing each other out even with the band pass filters? The wires are separated by about 5 ft..Lets say that I wanted to run SO2R on 20m and 15m, would that be possible since they use the same feed line? I see that in some stations, some use a triplexer but would I have to take that out to do 17m /12m outside of contests? I am assuming that I can't just plug in the 20-6m feed line and be able to transmit on 20m and listen on 15m simultaneously or can I?

Thank you so much for your time,
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Wyatt Law

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Posted 2 weeks ago

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Michael Walker, Employee

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Hi Wyatt

If I read that correctly, yes, you have 40M-6M all band antenna.

If you only have 1 antenna, then the 6400 is good enough.  If you plan to expand and you have the budget, the 6600 would be a nice upgrade.

You could do SOR2 on the 6400 actually and you would not need the band pass filters.   At 100 watts, you would have some RF bleed through but the 3rd order filters would handle it.  If there is a problem, you will get a front end overload message.  

This is why we also have a 30 day return/exchange program that allows you to do these type of tests.  Many do get the 6400 and then upgrade to the 6600 series.

Mike va3mw
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Michael Walker, Employee

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Hi Steve

Gotcha.  The non-resonant antennas become very high impedance, so aren't usually a bit issue to deal with.   If the 40M is on a unique feedline, then you will need to choose unless you have a 6600 or a 6700.  

With the 6600 and 40 and 20 on different feedline, you can do SO2R without additional filters since you have 70db of band rejection.    For 20 and 15 on the same feedline, you are ok on just a single SCU radio., but it would require testing.

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Wyatt Law

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Thank you for the reply guys. Yes the 40m section came with the Hex kit and is an independent rotatable dipole with it's own distinct feedline. I forgot to mention that I can run up to 500 watts. Is it still possible to do SO2R without interference with that amount of power?

And for what I understand, with the 6600, I could transmit on 20m and simultaneously receive on 15m while transmitting even with those bands using the same feedline?

Thank you
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Steve K9ZW, Elmer

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@Wyatt - I've read conflicting information on this.

The Hexbeam I have at my summer house is a single feedline version, but I will have a triple-feedline Hexbeam running at my regular house later this year.  Won't take much to run some tests then.

You share the same concern that compromises that work a modest power levels may not work when you add enough power to go QRO .  

Returning to the number of SCU in the radio, in general two use two antennas independently and simultaneously it will take a 6600, 6600M or 6700.

Or in a less coordinated way more than one radio could be used.



Blog:  http://k9zw.wordpress.com  
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Chris - NZ6T

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Thank you so much for your comment. That's my exact question that I was about to ask. I have the 6600 and about to setup the 2nd antenna. I shouldn't have interference from the other antenna?

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For SO2R you will need a Flex 6600/M or 6700 running in full duplex mode.  You need to be able to listen to one band while transmitting on another band.  The 6400 won't do full duplex. 

In your case, in order to use a single feeline you will need a triplexer to split the bands (20, 15, 10) out to the radio.  You will also need bandpass filters in addition to the triplexer to get enough separation.  Something like this https://www.dxengineering.com/parts/dxe-200fd-p  You can

I think you will be dealing with interference even with filters since your antennas are so close together.  Especially if you are plannning to run 500 watts or more.

I have seperate dipoles that are close together and have interference even with filters at 100 watts.  It doesnt take much power to cause interference.

SO2R requires very carefull antenna and station planning to eliminate interstation interference.