Thursday, 9 May 2019

Icom IC-9700 PTT switching - something I do not understand.

EDIT - now that I have an IC-9700, here is my first view of it ..
EDIT - This posting has now been made redundant after 2 years waiting by the DX Shop PTT multiplier - see here.

I have, of course, been watching developments on the IC9700 front for some time. It looks like and interesting radio for those of us who work on both 144MHz and 430MHz, and adds 1296MHz for good measure.

Maybe I have got this wrong, but it appears to me that the 9700 cannot switch different linear amplifiers on its different bands.

This is not such a hard thing to do. My IC7100 can do it. You can switch the two pins on the 13-pin socket between either working HF and VHF separately, or 2m/70cms separately. This is something I do. The IC-7100 has a "standard" 13 pin Icom output socket. However, the IC9700 seems only to have the other "standard" 7-pin socket. This has many things which I don't need, like RTTY switching, but it only has one PTT output pin.

Here is how the IC-7100 does it (one output is called HSEND, and the other VSEND) ...
IC-7100 manual showing clearly how to set the two separate PTT outputs.
As usual, click the images to enlarge if necessary.

You select what you want in the settings ...
IC-7100 manual showing how to select the automatic PTT band switching.

I do not own an IC-9700 and I have to rely on the "basic" version of the manual published by Icom UK. This does not show almost all of section 2 which would reveal the details. However that manual does show an explanation of the pin outs for the accessory plug ...
IC-9700 "basic" manual showing just one PTT output.

Now, as I say, I don't have an IC-9700 so I cannot verify if they are indeed being supplied with the 7 pin socket. However, elsewhere in the manual there is an explanation of how to set the single PTT output to work on specific bands
IC-9700 "basic" manual showing how to set the single PTT output.
This is, of course, consistent with the wiring details shown in the other part of the basic manual. It appears from this that you can set the single PTT output to on or off on any specific band, any combination of bands, or none.

It seems strange to me that a rig with three RF outputs only has one output for switching linear amplifiers. With the IC-7100, for instance, I can set it up with my 2m amplifier on one RF socket, and my 4m amp on the other socket, and it decides which amp to key. The same goes for 2m and 6m, and I have had it set that way too. You could also do this in the IC-7100 for 2m and 70cms, using a diplexer, but I have never tried that. I would have thought that this would have been a pretty obvious arrangement for the 9700 too.

I do wonder why the 9700, a radio with three RF outputs on the back, has only one PTT output, whereas the IC-7100 has two RF outputs and has full flexibility as to which PTT works with which. Why does the 9700 have the 7 pin plug when even the IC-7300, which has only one RF plug on the back, has the 13 pin plug. The IC-9700 seems to have taken a step backwards here.

From what I can see, the IC-9100 also had the 13-pin socket and the two PTT output, so if I was was replacing an IC-9100 with a IC-9700 I would be pretty miffed about this. It was a development of the 7100 system, allowing some limited choice between some of the bands. Shown below, from the 9100 manual, is the paragraph I would have wanted to see in the 9700s manual ...
The IC-9100 manual showing how it should be done.

OK, I have not seen a UK version 9700, nor even a full manual. Hopefully some 9700 owner can come on and tell me that the rig did, eventually, sell with the 13 pin plug and even the basic connectivity of the 7100 or 9100. If so, I can happily delete this post.

Is this a deal breaker for me? Probably in the sense that an IC-9700 would be a very good single band rig for me, but I could not use its multi-band capability. Sure I could rig up a switch to turn the PTT between the amplifiers, but I would only need to make one mistake with that to blow up my mast head pre-amps. I did not go to all the trouble of sequencing them to risk sending RF up to them with no PTT active.

I do not rule out getting an IC--9700, but it would be limited by this issue. I cannot see myself going into the menu to change the PTT settings every time I change bands, and the consequences of forgetting or getting it wrong are too expensive to contemplate. And anyway, isn't this what a multi-band radio is supposed to avoid? If the feature was worth putting in the 7100 and 9100, why leave it out of the 9700?

I have thought up a circuit which would RF sense the outputs and turn the PTT in line with that. This would mean that only the first transmission would go without the matching PTT - thereafter it would stay switched until I changed band again. But how often would I need to do that before the pre-amps died?

If you do not use amplifers and pre-amps this does not matter to you. Until you come to sell it of course, when such things make or break second hand sales.

It seems to me that it would have been sensible for Icom to have carried over the socket, the circuity and the software from the IC-9100 to the IC-9700 so that the very many VHF-ers who have multiple linear amplifiers could use them. After all, Icom had already figured out how to do it more than five years ago on the IC-7100.

But then again, are the production models supplied as the manual I have seen suggests? I hope not.



GM4FVM (EDIT - not just linears, but SHF transverter control is affect by this issue too)


  1. I can confirm that the 9700 supplied to me has the 7 pin socket.

  2. Gav
    Thanks,Gav now I know.
    It should be possible to build a little box which reads the CIV and switches the PTT accordingly. I just don't know how to build one ...

  3. Replies
    1. Gav. Goodness yes. The 9700 looks like a great rig. I am beginning to think that they have left off that plug and maybe one or two other things to make a more up-market one later. The equivalent of the 7610 to the 7300. That might even have more bands, more knobs, full 2 band operation, and the dreaded (13 pin) plug at about twice the cost of the 9700.
      You can see that as I have 7300s rather than 7610s that I prefer the basic offering, but in this case ...
      The CIV box I have in mind has a simple CIV decoder (maybe an Arduino) and 3 relays (or solid state switching). It just reads the CIV and switches between the relays to select the PTT. No need to sense the PTT from the CIV as it comes out on a different pin on the same socket as the CIV does. Three LEDS on the box to show which one is selected an fail safe all three work if the box loses the CIV signal.
      Timing and sequencing are not an issue as the PTT is still controlled by the DC line coming straight out of the rig, all the relays do it switch it about.
      Except I am not about to make one.
      Somebody should make it and sell me one.
      This is the consumer society and the VAT I will pay will help the NHS plus I am employing someone to make it. Home brew? Yes, when I get the time.

  4. PIN 3 supply via a sequencer last stage +5V. See availiable sequencer f.e.

  5. Yes, I have sequencers and I can do that. But what you suggest does not answer the question - it just trips the PTT on each band. The point I was making is that the IC-9700 does not have separate PTTs for more than one band. Jim

  6. I understand the question ... but get these problems to have a separate command .. I think they have simplified by providing the simple exclusion of what is not needed at that moment .. in fact the concept does not make a turn, a PA not managed by PTT is simply pass-through ... the preamplifiers are managed by an external unit called sequencers type DCW 2004 B which can energize the same directly via COAX cable as RTX does directly from the RF socket for each individual band .. or as I did DO NOT use it online on the single Coax-RF to avoid having QRO problems with large EME PA !!! but taking the DC from it and placed on an RG58 that brings DC directly to the Preamp. it can also be doubled if necessary, but the difference is that with these external units you can use the PTT in a different way regardless of the configuration set by the PTT PA Radio menu.
    The problem does not arise for ON / OFF Preamply that can always be controlled from the front of the sequencer ... clearly three independent units are needed, the operating voltage of these will be taken directly from ACC1.
    I note that in this way there is a wide choice on what to do for each type of different setup or radio, in any case I underline a concept that the PTT is used to manage the PA therefore if also the command is UNIQUE and all those present are on and they are switched in transmission, only the one in which they will transmit will supply power, or what is not needed will be switched off .. even without my solution mentioned above, the preamply will also be managed in unison "if not excluded from management in the radio menu "so in any case PASS through and in this case ... then the problem does not exist since the Preamply power standand is at rest no DC !! Impossible to cook them .... 73 & DX !! Steve IK4DRY

  7. What about trying to do duplex as in Satellite operations where you need a preamp on for the RX band but off for the TX band. I see no way to do this for standard preamps (not fed DC via the coax) unless a Bias-T picks off the DC to power a set of relays and the preamps. It would have been SO much easier to do it the way the older Kenwood TS-2000X does. A PTT closure for each band with individual delays too. Icom seems to have screwed the pooch as we say on this one.


  8. Sean. Thanks. You are absolutely correct. The TS-2000 does it correctly, just as the IC-7100 and 9100 do a reasonable job for two bands anyway.
    Steve. I want to have my amps controlled separately by my radio. Why not? Is this an unreasonable expectation? This was available with previous rigs. It wasn't difficult for Icom to do. Yes sure I could turn the amps off and on, but why go backwards when I did not need to do that before? I am not going to switch them to tx without driving them as I do not want spurious oscillation.
    Hey, I am a radio amateur. I do stuff and try to advance my hobby. Of course I want everything to follow the band selection. We have been trying to do that since I thought it was a neat feature of my Yaesu 2m transverter in 1978. I will build something to do it better in future. What is the problem with that? OK, the IC-9700 is a great rig but in my opinion this detail is a stupid gaff on Icom's part. Why shouldn't I point that out?
    If you are happy with things as they are Steve, fine. Surely I can set my own standard and try to rise to it - and if I can, why can Icom not do it too?
    73 Jim

  9. hello jim,

    I also have a 9700 and the PTT problem.

    It is annoying at the price that there are no different exits for the bands.

    I looked at the circuit diagram and there is theoretically a solution. For each band, the PTT is also switched on the KOAX socket. So either you listen on the HF for the PTT signal or you solder the signal out of the way in front of the C.

    I hope you have received my qsl card.

    greeting Ronny DG5BRE

  10. Hello Ronny
    Yes, I have your QSL card. Many thanks. Thank you too for a nice QSO. We should work again soon.
    I agree about the IC-9700. This would not have been difficult for Icom to organise. So it is the way it is, and we need to work around it.
    Jim GM4FVM

  11. A company called "The DX Shop" (I have no connection with it or anyone who works there) are going to produce an external unit for switching up to 3 amplifiers. However, at £60 including VAT it's not an inexpensive solution...
    Details at

  12. Thanks for that David. I had not heard about it.
    The thing is that if you are going to do 1296 with the IC-9700 you need to add GPS (or I think you do). And then if you want to work multi band you have to add this. All it would have taken was a bit of sense from Icom and these issues could have been covered easily in the design stage - plus the stereo USB output and the preamp controls could have been explained in the manual.
    Anyway, I have not had time to get on the air and certainly not time (couple of days I think) to build the mirco-PC solution to this issue I bought from I could see that the dxShop answer would be good for the 9700 and the other one I can build for the IC-7300.
    I bet he will sell loads of these.
    By the way, the other one is the Band Decoder Mk 2 kit from Remote QTH. It reads the CIV info and could select the right linear ... but there is a lot of building and programming to it and it is even more expensive. I guess it would be more use for an HF rig. Unlike the dxShop one, it is not dedicated to the IC-9700.
    73 Jim GM4FVM

  13. I have the DX Shop's port manager. It works great, inexpensive, even to US. Highly recommended. I have used it in several contests, no issues.

    Steve, N4JQQ, EM55

  14. Steve. Good news. Thanks for another validation of this useful item.
    73 Jim GM4FVM