Full-Duplex Satellite Operation on Flex-6300

Ron Parsons

If I understand the User Guide section "28.3.2 FLEX-6300 and FLEX-6500 Full Duplex" correctly, it says that FDX will be enabled ONLY if the receive port is XVTR in receive-only mode.

My current mode of operation (pre-1.5) is to use the XVTR port as the transmit port and ANT2 as the receive port to the transverters. This allows "semi-full-duplex" (receive audio muted but the waterfall on receive is active).

If I use 1.5 in this mode, I can enable FDX but the receive audio is muted as before.

If the first paragraph above is correct, then I will have to limit (in satellite mode) the power output to ANTx to the maximum transverter TX IF input level, in my case +5dBm. And use the XVTR port as the receive port.

Am I undertanding FDX for the 6300 correctly?

Ron W5RKN

Ron Parsons

Additional questions:

1. Is it possible to transmit outside the amateur bands using ANTx on a Flex-6300?

2. Is it possible to limit the power output on ANTx on a Flex-6300 to no more than +5 dBm?

Ron W5RKN

Tim - W4TME

For your original question, you are understanding the limitations of FDX on the 6300 correctly.

For your follow up questions...  
 
Q1 - no, it is not possible to transmit out of the ham bands on the 6300.

Q2 - no, the minimum wattage output from the PA is ~1W.

W0DHB

Tim, some followup questions/statements to Ron's postings For FDX on a 6300 given that the TX antenna must be on xvtr and TX on ANT1 or ANT2 AND the 6300 will not transmit outside of Amateur bands on ANT1 or ANT2 this really hoses up doing full duplex satellite work with the 6300 (and maybe the 6500??) and xvtr's . If either. 1) RX could go on ANT1 or 2 and TX on XVTR (preferred) OR 2) ANT1 or 2 could transmit outside of amateur bands (with restrictions to keep it legal of course like power, etc) The 6300 could be used for full duplex satellite work. Are either of these scenarios technically feasible ? Is there another scenario that might work ? Thanks Dave W0DHB

Ron Parsons

As Dave, W0DHB, and I have stated above, the method FDX was implemented for the 6300 make it nearly unsuitable for use in Satellite communication with most transverters.

In a response to another thread on this subject prior to the release of v1.5, Steve Hicks said:

"I don't see an easy way to do full duplex with a transverter on a FLEX-6300.  You could conceivably use the ANT1 port for receive, but in my microwave station I have a rule that nothing can be hooked up that can physically damage anything if there is operator error.  I f you hook a transverter receive IF port to ANT1 on a FLEX-6300 and you forget and send 100W into your IF port, you will damage the transverter.  So I do not recommend this."

I do not disagree with Steve's concerns, but the way FDX was implemented on the 6300 has the same problem that Steve warns against, but adds other problems. 

The implementation requires ANT1 or ANT2 for transmitting. It's possible (by mistake) to transmit 100W into the transverter -- not good. And as Tim confirms the use of ANTx does not allow use of 6300 frequencies out of the ham bands -- a necessity for most transverters for some satellites.

My implementation of satellite use with transverters on the 6300 uses the XVTR port for transmitting, eliminating the problem of over-power and allows use of out-of-band frequency for the transverter.

My implementation does have the possibility of transmitting into the receive transverter by mistake on ANTx, but the Flex implementation has a similar problem.

I have operated for several years with a similiar configuration (6300 as well as a 1500/3000 setup).without mishap by automating the switching between the 6300 and the transverters.

I would like to understand the engineering reason behind the way Flex implemented FDX and why it could not have been implemented the way I use it with success.

Ron W5RKN

Rick

I too am a satellite operator and Flex 6300 owner. I second both Ron and Dave's comments. While I have not yet installed version 1.5 after reading this thread is appears that it is not offering what we in the satellite community had hoped for. Too bad and discouraging. Is there no possibility for improvement in FDX performance and versatility? 
Rick, W2JAZ

Ed.G

With FDX enabled you should be able to listen on ANT1/ANT2 at the same time you are transmitting on XVTR.

The only restriction is that you can't listen to your TX Slice audio unless the RX frequency of the TX Slice is more than 12kHz away (this stops echoes). Does the full-duplex operation with satellites require you to receive on the same frequency as you are transmitting? 

If you do need to listen on the same frequency this can be accomplished by using two slices. The slice that is not the TX Slice will receive the audio with FDX enabled.

Ron Parsons

Thanks Ed. 

My radio audio control box was muting the RX audio when I was transmitting. I fixed that and I now get audio when transmitting. If I turn off FDX, then the 6300 does mute the audio when I transmit.  

So now I believe the only remaining problem is the documentation is section 28.3.2 of the user guide relating to FDX on the 6500 and 6300 which says you must receive on the XVTR port and transmit on the ANTx port.
 
I really appreciate you quick response on this issue.
 
Ron W5RKN

Mike KD2CJJ

Ron,  Can you summarize?  Full-Duplex on Satellite is very new for me but very interested in getting to.  My 6300 is on the way so Flex is very new to me too...

Thanks!

W0DHB

Ed To answer your question , No, full duplex SAT operation does not requires you to TX and RX on the same frequency. The only operations that require TX and RX be the same (or real close ) is Packet digipeating and this is done half duplex. Thanks for clarifying FDX operation with the 6300. Dave W0DHB

Ron Parsons

Ed and Dave

I believe the "same frequency" Ed was referring to would be the frequency in the 6300 after/before transverting.Both of my transverters convert to/from 28 MHz, but I have not run into a satellite that uses frequencies that would be within 12 kHz in the 28 MHz band.

Ron

Ron Parsons

To cap off this thread, I can report having several full duplex QSOs on satellite FO-29 a few minutes ago. My downlink signal was very clear and the delay was about as expected. 

Ron

Ron Parsons

Mike, email me off-line at w5rkn@w5rkn.com and we can discuss this. Ron