Our in-house designed PTT multiplier for the Icom IC-9700 transceiver.
Whilst the Icom IC-9700 has gained a solid reputation as a VHFUHF transceiver it has the limitation that there is only one PTT output on the back to operate linear amplifiers. The nature of being a 144/432/1296 band rig means that if you want to add amplification this is usually done with separate amplifiers for each band. This then presents the problem of how you command these amps individually into tx on the band you want to operate on. You could parallel up the PTT line and key all the amps and just turn on the amp you need at the time, or…
Introducing the PTT Multiplier from The DX Shop:
The PTT multiplier provides THREE separate, BAND SPECIFIC, amplifier PTT Phono connections and automatically tracks the tx band in use putting only the relevant PTT connection into tx.
The PTT multiplier is powered from the rig and connects to the IC-9700 Remote and ACC1 sockets using leads provided. The ACC socket is replicated on the PTT Multiplier so you can still daisy chain on other devices that use the ACC1 socket if you wish.
It has an integral PIC processor that communicates with the IC-9700 via CI-V and extracts the band data so it knows which TX band to PTT. As it monitors TX frequency specifically it will handle cross band and satellite operation selecting the correct output for the tx band in use.
Amplifier outputs are RCA/Phono connections and a bi-colour LED next to each tells you which band is selected (Green) turning to Red when the rig is in TX.
Each output can switch to ground up to 100V at 2A if needed (so if you want to switch other things as well/ instead of an amplifier you can…)
The PTT multiplier is supplied in an aluminium enclosure circa 100 x 50 x 30mm in size and comes complete with 400mm long 8 pin DIN and 3.5mm mono leads to connect to the IC-9700.
Does it track the TX band properly?
Yes it does – it will always tx on the correct band whatever you have highlighted on the rig
What about satellite mode – I have heard this swaps things about a bit?
In satellite mode the 9700 tx band is from sub not main – the PTT Multiplier detects this automatically so the correct tx band is chosen for satellite mode.
How quickly will it operate the PTT line?
The PTT Multiplier will pull down the chosen PTT line in <30 microseconds (yes microseconds not milliseconds) of the command exiting the ACC socket on the IC-9700
What about communications protocols with the IC-9700?
The PTT multiplier requires the IC-9700 to be set to the default 9600 baud.
CI-V transceive mode can be on or off as you require (the speed of initial change of the PTT multiplier when you change band is slightly quicker with transceive on but at worst it will detect and change within 1 second of a band change whatever the status of the transceive setting).
The USB and CI-V Remote must not be ‘linked’ in the settings on the 9700 as this could cause potential software conflicts.
Can the CI-V be used from the USB port on the IC-9700 at the same time for other things?
Yes it can – this will not interfere with the operation of the PTT multiplier.
What about future upgrades?
The PTT multiplier has an on-board PIC microcontroller. Firmware for this can be upgraded by use of a PicKit3 interface and a suitable hex file to upload.
Will the PTT multiplier work with other rigs?
No – the unit is programmed to recognise and function specifically with the Icom IC-9700 only.
Your website is trying to charge me as much for shipping as the device itself!
The website defaults to ship DHL/Fedex to all destinations outside of the UK. Because the PTT Multiplier is light weight and small volume we can ship this product Royal Mail post at a saving on the courier rates. Please drop us an email and we can work that out for you (and we can send a PayPal Invoice for you to pay on-line if you wish to proceed). Royal Mail shipping will be slower than DHL/Fedex but will still be a signed-for service.
There is a short video demo of a pre-production board on You Tube here: https://youtu.be/rvNdiBZABV4
(Note production units are housed in an aluminium enclosure and the LED’s are Green on RX changing to Red on TX)