Wisycom CTK-38 Invisity Transmitter

Wisycom CTK-38 Invisity Transmitter


£1,746.65 inc VAT (£1,455.54 exc VAT)inc VAT

  • VHF band (10MHz bandwidth within 140 to 250 MHz) Example: 170 to 180 MHz
  • 16 switchable frequencies
  • High output power (300 mW)
  • Top receiving quality from Invisity receivers

Call To Order

Call To Order


Wisycom CTK-38 Invisity Transmitter

The Wisycom CTK-38 Invisity Transmitter is designed for the Phonak Invisity range of miniature in-ear receivers.
The CTK38 system is composed of:
1 x  CST38, VHF transmitter module for desktop use
1 x PSP910, 100 to 240 Vac power-supply


  • VHF band (10MHz bandwidth within 140 to 250 MHz) Example: 170 to 180 MHz
  • 16 switchable frequencies
  • High output power (300 mW)
  • It assures the top receiving quality from Invisity receivers, thanks to the special audio treatment of the modulation.
  • Provided with PTT (Push to Talk) and (optional) VOX (Voice-controlled operation).
Switchable channels 16, preset in the 140 to 250 MHz range.
Switching-window 10 MHz.
Frequencies microprocessor controlled PLL synthesizer circuit, with 25 kHz minimum step [1].
They are easily PC re-programmable by the optional “UPK 100 Programming kit”.
Frequency error < ±5 ppm, in the rated temperature range.
Temperature range -10 to +55 °C.
Spurious emissions < 2 nW.
Transmission activation Remote PTT (Push To Talk) circuit, wired to ¼” (6.3 mm) mono jack connector.
The transmission is allowed when the central pin (hot) is connected to external ring (ground).
Modulation FM (peak deviation = ±5 kHz).
Mod. audio input transformer balanced, floating.
Mod. audio input level Micro / Line switchable, and externally adjustable between

  • Micro = -64 to -34 dBu (0.5 to 15 mV) Input impedance = > 2 kOhm
  • Line = -22 to +8 dBu (60 to 1,950 mV) Input impedance = > 10 kOhm.
Peak-limiter automatic, with dynamic-range > 30 dB over the level set for the nominal modulation.
NR system compressor circuit with noise-gate, specially adapted to the Invisity receivers.
AF bandwidth 200 Hz to 5 kHz (-3 dB).
Distortion < 0.5 % (0.25% typ.).
SND/N ratio > 80 dB (83 dB typ.), CCITT measured.
LED indicators
  • Transmitter On (red LED)
  • Limiter On (yellow LED).
Powering 10.5 to 16 Vdc, 300 mA max. (negative ground).
Dimensions 40 x 120 x 175 mm.
Weight 700 gms.

Wisycom CTK38 Manual

Wisycom CST38 User Guide & Specs


All orders are delivered via next day tracked carrier. When placing an order please provide a suitable e-mail address and mobile number.

On despatch you will receive a notification from our carriers DPD along with updates right up to the point of delivery.

On the day of delivery you will get an accurate 1 hour time window for the items arrival.

You’ll even be able to contact your driver and track his progress!

Track your parcel here: DPD Tracking

Delivery Rates

We deliver Worldwide!
Can’t see your country in the list below? Don’t worry, let us know and we’ll add it!

Country Delivery Cost Ex vat
UK Mainland £6.66 – Next Day Courier
UK Mainland £2.46 – Royal Mail 2-3 Days
Austria £20
Belgium £15
Bosnia £65
Bulgaria £35
Croatia £30
Czech Republic £25
Denmark £20
Estonia £30
Finland £30
France £15
Germany £15
Greece £35
Hungary £30
Iceland £65
Italy £25
Jersey £25
Latvia £35
Lithuania £35
Luxembourg £15
Netherlands £15
Norway £65
Poland £30
Portugal £30
Republic of Ireland £25
Romania £35
Serbia £65
Slovakia £25
Slovenia £25
Spain £25
Sweden £65
Switzerland £50

Returns Policy:

Not happy with your purchase?
Don’t worry, you can return goods ordered from us at any time within 14 working days of receipt for a full refund or for an exchange for a different product. Before returning any items, notify us so we know what to expect.
All we ask is that you return the items to us in the same condition that we supplied them to you. Please package the items up securely and safely so that they are not damaged during transit. Uuse the original delivery packaging where possible.

We strongly recommend using a recorded or tracked delivery service. Please send the return items to:
Returns, Raycom Ltd, Unit 8 Abbey Court Lane, Abbey Lane, Evesham, WR11 4BY

Returns Terms & Conditions:

Returns of an order for a refund or an exchange:

  • Cost of return – The costs of returning goods to Raycom shall be borne by you, the customer, in all circumstances without exception, unless otherwise agreed upon with Raycom.
  • Loss & damage – Return items must be packed suitably and insured against the event of loss in transit. Raycom Ltd will not be responsible for lost or damaged returned goods. Lost or damaged goods may effect the level of refund on equipment.
  • Delivery costs – The original postage and packaging costs will not be refunded under any circumstances unless agreed with Raycom Ltd
  • Upon receipt of the goods, to Raycom Ltd, and with prior arrangement, we will give you a full refund of the amount paid or an exchange credit as required and agreed

The right to return goods to us will not apply in the following circumstances:

  • in the event that the product has been used, in any way, shape or form, other than limited useage when the goods are unpacked
  • in the case of software, audio or visual products, where the packaging has been unsealed, broken or is incomplete
  • to any products that we have made on special order and or customised specifically for you

The provisions of this clause do not affect your statutory rights. For more information, please see our Terms & Conditions, or should you have a question regarding this policy, please do get in touch.

Cancelling an order:

In accordance with the distance selling regulations, any order with us can be cancelled before we have dispatched your items. In this instance we will refund you in full using the chosen payment method. Terms for our cancellation and returns policy.

If you wish to cancel your order:

  • Notify us by email sales@raycom.co.uk before we have dispatched the goods to you, or
  • where goods have already been dispatched to you, by returning goods to us in accordance with our returns policy