TVRG (Thames Valley Repeater Group) have a number of VHF Key Radio mobiles for sale. These are programmed for 2m frequencies as detailed in the separate document OP5_KM3000 4000 Channels 2024. From May 2024 the frequencies have been updated. More information is available here.

These radios are all working prior to sale and are sold “as seen.”

A Price List is available here. This gives details of accessories and carriage costs together with payment details.

These radios first went on sale in July 2022 and the majority of radios sold up until March 2024 have been the KM3000 type. Our present stock of KM3000s has now been sold and any orders after March 2024 will be KM4000 radios. There is no difference between the KM4000 and the KM3000 in appearance and performance, with the following two exceptions.

The KM4000 does not have a transmit time-out. It also reverts to Channel 1 when power is completely removed. To clarify, if power is kept connected to the KM4000 radio, and it is switched off using the front panel on/off switch, it will retain the last used channel. However, if the power itself is removed then it will default to Channel 1.

The basic specification for all radios sold after May 2024 is as follows:-

Power input:- 12V DC 6 Amp max

Power output: 15W

Maximum of 256 channels, 207 in use. Set up for 12.5kHz channel spacing specification and the appropriate deviation.

A speaker microphone and mounting cradle are included. The power lead is 100mm long terminating in a 2 pin Molex connector. You may want to cut this off and replace with a connector of your choice. Alternatively, a made up 800mm long unfused power lead is available at an additional cost of £4.00. If you want to make up your own lead, we can supply a mating connector kit for £2.00.

The radios are programmed to function as follows:-

FRONT PANEL CONTROLS

On/Off (press) and volume control for the speaker microphone.

Microphone socket.

REAR PANEL

SO239 type flying lead for the antenna.

Flying lead for power, terminating in a 2 pin Molex connector.

As standard, the KM4000 comes with an RJ45 female flying lead. If you want a 15 Way Molex connector, we have a limited number of spares, which we can fit for an additional cost of £2.00. The majority of KM3000s had the 15 Way Molex connector but there were a number with the RJ45. These connectors can be used for programming. TVRG have a number of ready made programming leads which can be used for either the Molex or RJ45 version – simply remove the bottom cover of the radio and plug this lead into the 7 way header, where the Molex or RJ45 is plugged into. Refer to Note 13 on the “downloads” page. These leads cost £10.00 each.

FRONT PANEL DISPLAY

The display, which is backlit, displays the channel number and if the channel is simplex, the frequency or if the channel is a repeater channel, the callsign. The radio is programmed for all U.K. 2m FM analogue amateur repeaters as listed on the ETCC website in April 2024, together with simplex channels. In addition, we have added some channels used for packet radio.

If you are intending to use the radio for packet use, then please read the document Key KM3000 Squelch setting for Packet Radio 2023.pdf, which is on the KM3000/4000 section of the downloads page. Note, this only applies to the KM3000, not the KM4000.

The lower line of the display gives an indication of the received signal strength. This is shown as “blocks” on the LHS of the display and a relative number indication on the RHS.

MICROPHONE CONTROLS

LEFT/RIGHT arrows – change channels. If you press and hold either button, the channels will change quickly, stopping when the button is released. Looking at the microphone, the left-hand button is “Channel down” and the centre button is “Channel up”. The right-hand button is for Scan.

END – stops/starts scan. Note: when a signal is detected the scan remains stopped for 10 seconds or less if the signal disappears and then resumes scanning. An “S” is displayed in the lower RHS of the display.

Some microphones may be labelled 1, 10, 100. 1 and 10 are Down/Up channels and 100 is Scan.

All the repeater channels are programmed with CTCSS encode and decode. This is because there are digital repeaters throughout the UK, and these will be annoying if the receive is not protected by CTCSS. If you want to disable the CTCSS decode, then press and hold the Scan button and at the same time briefly push the PTT. The radio will not transmit but will show “D” in the lower RHS of the display. Repeat this procedure to resume normal CTCSS decode operation.

CHANNEL PROGRAMMING AND SCAN:

The radio is capable of holding 256 channels.

The first 8 channels are programmed as simplex channels upwards from the calling channel V40 (previously S20). The next channels are all the analogue 2m FM repeaters listed alphabetically from GB3AA up to GB3ZA. These were taken from the list on the ETCC website (ukrepeater.net) in April 2024. After the repeater channels (and one for the ISS – International Space Station) are four packet frequencies that have been requested by people wishing to use these radios for packet radio use. The remainder of channels are the simplex channels below 145MHz starting at 144.625MHz finishing at 144.800MHz, the APRS frequency. Finally, you have the simplex channels from 145.200MHz to 145.4875MHz. The radio “rolls over” from Channel 256 to Channel 1 in both directions and this means all the common simplex channels are consecutive.

In order to provide a radio that can be used anywhere in the U.K., we have programmed every U.K. 2m FM analogue repeater as a separate channel with their specific CTCSS frequency. The repeaters are listed alphabetically by callsign, which is shown on the display.

To scan every repeater would take a long time and to minimise this the radios have been programmed as follows:-

It scans the most used simplex channels and at least one of each of the 17 repeater channels. These repeater channels have been chosen to be those in the central south-eastern and south-western areas of the country. This is because of where the radios are initially being sold. However, if you live outside these areas and see a repeater on one of those channels, you can disable the CTCSS decode and identify which repeater this is, and then move to that channel, which has been programmed. The chances are you that you will know your local repeaters and their frequencies.

You can stop scanning by pressing any of the microphone buttons or PTT.

Contact TVRG using the email sales@tvrg.org.uk