Monitoring 6M and HF at the same time

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I can receive 6M and HF at the same time but it doesn't allow me to use the 6M yagi and the HF antenna.  It is either one or the other.  Is there a way to do this without having to change antennas for whichever band I want to use?
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Bob Brown - N8OB

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Posted 3 years ago

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Mark - WS7M

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Hi Bob,

Unless you have a 6700 the answer is no.  I asked this same question but with the 6500 and 6300 there is only one SCU (spectral capture unit) doing all the receiving so you are limited to one receiving antenna.
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KF4HR

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Bob - I'm not sure I completely understand your issue.  If you are trying to monitor 6M and HF at the same time without changing antennas, why couldn't assign one antenna to Ant 1 on one slice, and the other antenna to Ant 2 on another slice?  Or am I missing something? 
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Bob Brown - N8OB

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KF4HR - i can monitor both bands at the same time, but not on their correct antennas. I can only use either the 6M yagi (my ant 2) or the HF ant (my ant 1) but not both of them.  HF antenna doesn't like 6M and HF antenna doesn't like 6 Meters.  

Mark - Unfortunately, it sounds like I need a 6700 instead of the 6300.  The other alternative I have is to use my Kenwood TS590 for 6M but I would sure miss the spectrum scope on the Flex.        
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Bill W2PKY

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You could build a frequency sensitive combiner so both antennas feed into one antenna port on the radio; This would be a receive only capability, however.
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Dan -- KC4GO

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Only the 6700 can have a separate antenna, the 6500 and 6300 are limited to 1 RX antenna at a time. 
I have a Comet 250B  vertical Receive Frequency Range 2.0 to 90 MHz  that I use for this.
It's also used to listen to SW and Utility transmissions. Here is a review http://download.qrz.ru/pub/hamradio/antenna/comet/Comet-CHA250B-Review.pdf
While it's a compromise it allow listening to a large section of spectrum. Oh and you can transmit on it as well Transmit Frequency Range 3.5 to 57 MHz 
I use this when band hopping on WSPR. 
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Keith Ferguson

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Bob - it's dead easy. Just use a "duplexer" (incorrect use of the term, but that's what they call them). I do it on my 6500. Here's a link to an example, a Comet CF-360:

http://www.eham.net/reviews/detail/6522

Keith
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Bob Brown - N8OB

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Keith - The only problem I see with your solution is that it only uses one antenna for both 6M and HF.  At this time, I have a 7 ele yagi on 6M and a tri-bander on HF.  The 6300 only allows one antenna to be used at a time.  In order to use either antenna requires that I switch from ant 1 to ant 2 to receive on 6M and from ant 2 to ant 1 to use the tri-bander.  I can set the xmit to either one but not the RX.  There-in lies the problem.  If I set the radio to ant 1, I can receive HF and if set to ant 2, I can receive 6M but not both at the same time. I lose sensitivity on whichever antenna port the radio is not set to.  I hope this makes sense.
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Tim - W4TME, Customer Experience Manager

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There is another issue.  The RF preamp settings.  The preamp setting you will want to use on 6m will probably be too high for any HF band below 10m, so when listening to HF, you will have to turn the preamp off which will degrade your 6m reception.
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Keith Ferguson

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Bob - the device allows two antennas to be connected at the same time and used without switching. Typically, I use a doublet via an SGC230 auto-tuner for HF and a vertical 6M antenna.

The only issue I've run across is the one Tim (and Ken) point out regarding the pre-amp, which I find I can live with. I didn't experience Ken's heat problem because my HF ATU is between the antenna and the duplexer, I'm not using the 6500's internal ATU. The 6M antenna presents a good match without an ATU.

I think the issue that might make this solution unsuitable is if you want to use the internal ATU - as Ken points out, when it tunes up on HF it'll degrade 6M, and I'm guessing that the "native" impedance presented by the HF antenna may have an effect on performance of the duplexer.

Keith
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Ken - NM9P, Elmer

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WHen I first got my 6500 two years ago, i used a "DiPlexer" that separated HF from 6 meters and above.  It worked pretty well, except for the following:

1) there was a little bit of insertion loss

2) If I wanted to run the preamp on 6 meters, it also ran on the other bands, since they are all on the same SCU.

3) If I put the ATU in the circuit for lower frequencies, it degraded the 6 meter signal.

4) Diplexers are not designed to be used with high SWR, so if I used an HF antenna that had higher SWR and needed use of the ATUm it generated some heat and reduced performance in the Diplexer.

But it was fine for monitoring the bands, and casual use.

(But then I got the T-11....<grin>)

Ken - NM9P 
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EA4GLI - 8P9EH - Salvador

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This might not be the answer that you want to hear but,

Option A:
What about getting an antenna that offers you more range? The preamp issue presented by Tim is still there, but with a Hexbeam for example, you have 14,000 to 52,000 all in the same antenna and same coaxial line.

With a log periodic you can actually go from 7,000 to 30,000 MHz in one coaxial, granted, that is a massive antenna, but it is just a great combo with the Flex radio. My Logp hears OK in 6m and I can tune it to work that band. I have worked Argentina from Barbados in 50Mhz.

Option B:
If seeing activity on the band is what you want, you can get a fairly cheap SDR receiver just for 6m, like an SDRPlay, and connect it to a multi band receive antenna. You can use the same to add Air Band as well as 2m, 70cm and 23cm receive to your radio shack with a discone antenna. That opens up your receiving capabilities in the radio shack, allows you to see openings in the 6M band and you keep your TX antenna on TX2 of the Flex.
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Bob Brown - N8OB

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When ver 1.6 came out, I told the XYL that I was getting a new radio.  You should have seen the look on her face.  I can imagine what she would say if I told her I was getting a 6700.
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Mark - WS7M

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Bob,

I have a solution for you.  When you tell her you are getting a 6700 you take her outside and show her the new car you just bought her!  Trust me the concern over the 6700 will quickly disappear.

I just did this last night... we brought home a new Subaru Outback for my wife.  So my last radio purchase is now in the noise so to speak! 

Mark
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Bill W2PKY

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My wife likes the Tesla, probably stuck with the 6500 for now!
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Mark - WS7M

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Ouch!  That would hurt!
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EA4GLI - 8P9EH - Salvador

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I actually went for Option C, Tim. LOL

You can always tell the wife that you are buying the Icom IC-7851, and then tell her that you thought that was too much money and decided on the 6700 instead!

Reminds me of the joke: "My biggest fear is that, when I die, my wife will sell my radio gear for what I told her it cost"