TS-480 RFI - more information

[G3UEG]

The receive side of my system has been superb, but I have had serious problems with RFI when transmitting and have had to install a large number of ferrites to get to the stage of being able to transmit at the 100w level.

My approach has been to back off the various gains both in the radio as well as in the RRCs, so there is virtually no ALC being triggered, with just one led occasionally 

The interesting discovery is that most of the problem is when using the internal speech processor.  Testing has been on 80m as this is the only band I can hear myself on from my home operating location..  (100Km away)

Having got the SPE amplifier working I have discovered the following:-
1)  I can transmit 400w on CW
2)  I can transmit 400w on SSB as long as the PROCESSOR IS OFF
3)  With the processor on (even with low levels of processing) I cannot transmit more than about 50w

The RFI effect I am getting is a continuous "clicking" at about 2 per second which generates significant RF output. This happens as soon as I press the PTT and before I start speaking, and continues when I start speaking.

Does anyone have any ideas what I can do to solve this problem??
I have wondered about cutting the audio (RJ45 cable) and putting a 1:1 transformer in the mic circuit
Am not sure whether I should do anything else on the other wires.

Question for Mike..
What effect on the RRC performance is there by further reducing the Codec Input gain??

73,
Dave, G3UEG

[M0BPQ]

I can pretty much repeat the problems Dave is reporting with My TS-480 and RRC V2. When the comp is on, SSB is unusable. Should I do the op amp mod?

I also have an RRC mk1 and a IC-706G that I use on VHF/UHF SSB and I get excellent audio reports with that, even at 400W with the antenna only 5m away. I shall try that radio on HF to see if I get an RFI problem or if it is limited to the 480/MKII combination.

If anyone has any siggestions for Dave's problem please post it here so I can try it too.

73
Steve

[G3UEG]

Hi Steve,

I would be very interested in the result of your proposed test with the IC706, are you planning to try it with the V1 or V2 RRC?

I hope Mike can suggest the correct course of action re the Op-amp mod..

73,
Dave, G3UEG

[W6SA]

Have you turned off the pre-amp in the RemoteRig settings?  I had the same problem and the clicking would put the rig on the air before I even breathed into the mike. I turned it off and no more problems.

73,

Walt, W6SA

[G3UEG]

Hi Walt,

Thanks for the suggestion, but the pre-amp has been off from the beginning.  Also I have reduced the codec input gain down from the recommended level to try and tame it further.

Are you using the RRC V2? and have you done the op-amp mod?

73,
Dave, G3UEG

[W6SA]

Hi Dave,

Yes, I have version 2.  I admittedly have only made a couple of contacts while testing.  Audio reports were good with the pre-amp off and I have not seen a need to make the mod at this time.  Perhaps it will be necessary once I get into full operation.

I bought this unit for travel purposes and I don't do that very often.  I will probably have more use for it as a second operating position when the xyl insists I join her in the TV room and I want to try to work a DXpedition.

XYL just had major surgery so have not had the time to take it to a hotspot to try it out now that I believe I have finally worked all the bugs out of the basic setup.  Hope to do that later this week.

Good luck with your problem.

73,

Walt,  W6SA

[HB9AZT]

Hi Dave

Had an ACOM2000A at a remote location, running 1 KW out without any problems. Had to replace it temporarily due to maintenance by an Expert and lot of rfi-problems came up, computer crashed etc. Had to put ferrites in every line going to the expert, especially the power line is not clean and spreading rf in the rack. Amp is carrying CE-sign, but this doesn't help against RFI:-(

73 de Mark, HB9AZT

[M0BPQ]

Dear All,

I have tried my IC-706g/RRC v1 on HF and it works just fine. The same PSU/antenna with the TS480/RRC v2 (preamp off) gives the problem that Dave describes above. I guess the obvious solution is to switch the RRCs around and see what happens, but I hate to break a working system...

More news if I get time and courage to move things around.
73
Steve, M0BPQ

[G3UEG]

Hi Steve,

Useful info from the test.  I realize it would be pain, but two more tests..

1) TS-480 and RRCV1 and
2) IC706 with RRCV2

would be **VERRRRY** interesting.  I would be willing to help if you would like..

73,
Dave, G3UEG

[sm0mdg]

The receive side of my system has been superb, but I have had serious problems with RFI when transmitting and have had to install a large number of ferrites to get to the stage of being able to transmit at the 100w level.

Does anyone have any ideas what I can do to solve this problem??

I had the same problem but where able to cure most of it. I am now running the station at the gain/ALC levels intended and only have RFI problems on 40 meter which I credit to the antenna layout rather than the Remoterig / TS-480 combination. In short the fix was to turn off the "Codec inp preamp" setting in Remoterig and compensate gain in the radio.

Have a look at this message;

http://www.styrefors.se/sm2oan/remote/forum/index.php?topic=242.msg741#msg741

My MkII boxes have not been modified in the audio chain as suggested by Mike, I don't dare to mess with it as it works quite well right now.

73 de Björn,
SM0MDG
SE0X

[G3UEG]

Thanks for all the comments..

I don't get any problems when operating seriously in contests when I am actually at the remote site operating in person and running things at max!!
I have acquired an RF clip-on meter and cannot detect any RF current on the 50% of the leads I checked..
(I will re-test the meter itself!!!)

Bjorn..
The codec input pre-amp has been switched off from very early on.

Mark..
Could you describe more fully what you had to do to your SPE amp to "tame" it...   I have wound the mains cable abt 6 turns through an FT240-43 core at the amp end, plus a couple of clip-on cores at the other end..  I have also wound the PTT lead many times through a smaller core.  I have several clip-on cores on the RS232 lead.  I have put an RF common mode choke in the coax feed to the external antenna switch.

I went to the site yesterday again and as well as working on the amp as described above.. I have changed some of the ferrites of unknown spec to ones with Type 31 ferrite, which has higher loss than type 43.
The short RJ12 lead has three cores.
The Aux/Mic lead has 9 cores
The dc supply is wound many times round a torroid.
There are several clip-on ferrites on the ethernet cable and RS232 cable.

All of this made a very slight improvement..  I can now TX 100w barefoot with the processor on, and about 200w with the processor off.. both of these about twice what they were before..

Any thoughts whether there would be any point putting the radio RRC inside a metal box??

That is now 5 trips and 1000Kms to try to solve this problem......

73,
Dave, G3UEG

[LA7THA]

Hi Gents

I use Remoterig V1 TS480 and Acom 2000. Have used 1 Ton of ferite, decoupling capacitors etc. My wiring between RCC and Ts480 is all Shielded.
I also noticed that when Proc is on the audio out geting usles.
Hope someone find a solution on this

73 de Rune LA7THA

[on4iq]

I'm using a brand new ts-480, even with low power (<10watts) the audio is poor and levels extremely low. I'm not sure if its RFI or another issue. Has anyone similar issues.  When I connect the ts2000 with remote panel it all works OK and audio is really fine.

[PA0TCA]

Are you sure that you have not switched the common ground (gnd)  and the mike ground (egnd)

[G3UEG]

MIKE - Please help..

There are a significant number of us having the same problem. 

A number of questions have been asked to which no answers have been forthcoming,  I will summarise them here and would be grateful for some answers.

1)  What is the spec of the jumper wires.  I want to redo the jumpers just in case there is a bad connection.  The wires bend very easily and are difficult to re-use once they are bent?

2)  Would doing the mic gain mod help overcome the problems we are having?

3)  Would it help to put the RRC in a screened box?

4) Would it help to put a 1:1 decoupling transformer in the mic connection between the RRC and Rig?

5)  There are a number of errors and inconsistencies in the Kenwood documentation for the RJ45 mic connector 
    a) pin numbering is non-conventional
    b) the mic ground and system ground pins are swapped round in the User Manual
Can you confirm that the wiring schematic for the RJ45 lead from RRC to Rig,   and the jumper wiring diagrams are correct bearing in mind these errors.

73,
Dave, G3UEG