Ten-Tec OMNI-VI and VI+ Transceivers to Facilitate
Morse and Digital Mode Operation
Copyright 1999 Dave Bowker, K1FK. All Rights Reserved. Used with permission.
Owners of Ten-Tec OMNI-VI and VI Plus transceivers who wish to use the PK-232 for Morse reception and transmission as well as the digital modes will find these modifications easy to incorporate. Three different modification possibilities are presented for the user to select from for his particular station requirements.
The Ten-Tec OMNI-VI/VI+ requires the PK-232 PTT line to be routed to either the MUTE jack (for CW operation) or the PTT jack (for digital modes). Mods #1 and #2 provide manual selection capability to meet this requirement while Mod #3 provides automatic capabilities under control of the PK-232 software.
Mod. #1 (Figure-1) Figues 1 & 2
This modification applies to those who use the PK-232 for HF only. The Radio-1 / Radio-2 switch on the PK-232 selects the CW or Digital mode configuration of the OMNI interconnection. Select Radio-1 for Digital Modes and Radio-2 for CW.
Mod. #2 (Figure-2)
This modification applies to those who use the PK-232 for both HF and VHF and requires an external switch to route the PTT line to the correct OMNI jacks.
Mod. #3 (Figures 3 - 6) Figure3 Figure4 Figure5 Figure6
This modification consists of adding a relay to the PK-232. The PTT line is switched internally to the PK-232 and routed to the OMNI MUTE or PTT jacks via J8 on the rear of the PK-232. If you are using an external modem preceding the PK-232, this Mod is not for you! This modification does not cut any PCB traces in the PK-232 and is easily reversible.
Mount the W172DIP-5 relay on a 14-pin header and solder interconnecting wires to the header as shown on the schematic. Any 5 VDC SPDT relay having a coil resistance of 200 Ohms or greater and internal diode protection may be substituted for the W172DIP-5. It is recommended that the relay/header be wired on the work bench rather that after installing in the PK-232. Apply a small piece of double sided foam tape to the relay. A pencil tip soldering iron and ESD precautions arerecommended for making this modification.
1. Remove cover from PK-232.
2. Locate Jumper plug JP2 (just to the left of the RADIO 1-2 switch as you face rear of PC board) and remove the jumper between JP2-1 and JP2-2.
3. Apply a small piece of double-sided foam tape to the the relay/header and attach to the main PC board in location shown.
4. Dress the wiring harness against the PC board as shown. The two leads should be dressed towards the back of the PC board and connector J8.
5. Solder the lead from the relay/header pin-1 onto JP2-1.
6. Solder the leads from relay/header pin-14 to JP4-1 and from relay/header pin-7 to JP5-1 as shown. DO NOT REMOVE the jumper clips from JP4, JP5, or JP6.
7. Solder three leads to U18 as follows:
When your software places the PK-232 into the MORSE mode, the PK-232 PTT output (Q5-collector) is routed through the N.C. contacts of the relay and to J8-1. The external wiring harness carries this signal to the OMNI "MUTE" jack. When you command the PK-232 to XMIT, the OMNI will be put into the "semi-XMIT" mode and the linear amp T/R relay will be energized, and remain energized until the PK-232 is commanded to RECV mode. NO RF will be output until the PK-232 generates a Morse character(s).
When your software places the PK-232 into the RTTY mode, the added relay is energized and the PK-232 PTT output (Q5-collector) is routed through the N.O. contacts (now closed) to J8-2. The external wiring harness carries this signal to the OMNI "PTT" jack. When you command the PK-232 to XMIT, the OMNI will be put into the FULL XMIT mode and the linear amp T/R relay will be energized, and remain energized until the PK-232 is commanded to RECV mode. The OMNI will output RF to the linear. The FSK interface between the PK-232 DIN connector and the OMNI "MARK/SPACE" RCA jack shifts the OMNI frequency at 170 Hz shift.
On packet, the operation is same as for RTTY/ASCII, except the PTT line is energized ONLY FOR THE DURATION OF THE PACKET being transmitted. It is recommended that you program the OMNI "DLY" to at least 3 or 4 in this mode.