G4HUP Panoramic Adaptor Tap Board

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This circuit, which was presented as an entry level SMD construction project at the 2013 RSGB Convention, allows the IF of a rig to be tapped off at high impedance, and brought out to an external SDR, to give a panoramic display. See also the Radcom November 2014 Technical Feature article on the PAT board and its applications. Article reproduced with the permission of the RSGB

The PCB is just 40 x 25mm (approx 1.6" x 1"), and fits nicely in an FT817. In larger rigs it can easily be 'lost' in a dark corner!

In addition to the high input impedance amplifier, the PCB also provides for a low pass filter and an output attenuator.

For the detailed description of the circuit and its operation, see here

Both kits and assembled units are available - please go to Kits, Prices and Ordering

PAT Types

There are a few different versions of the PAT board, named according to the rigs in which they were first installed. However, the board can be installed in any rig. The following information should help you to decide which version to request:

Rig list
- Elecraft K1, K2
PAT 2k
- TS2k (2nd IF), TS790E (2nd IF), IC201, IC821 (2nd IF), TS700, IC910 (2nd IF), IC1271 (2nd IF) FT920 (2nd IF)
- FT736
- Transverter Rx output, 28-30MHz IF
- FT757GX, FT840, FT847, FTdX1250, FTdx9000, TS430S, TS440S, Tentec TT550
- FT450, FT817 (5V), FT857, FT897, FT920 (1st IF), FT950, FT991, FT1000, FT1000MP, IC703, IC706, IC746PRO, IC756 Pro III, IC7410, IC821 (1st IF), TS450, TS850, Alinco DX SR8T
PAT 140M
- IC1271 (1st IF), IC7000
PAT 146M
- Transverter Rx output, 144-146MHz IF

To check which PAT you need for your rig click here for information

Instructions for installation for the rigs below may help you find the right points in your rig, even if it's not listed.

There are no notes provided for the FT857, but since it is essentially the same radio as the FT897, the connection points are the same. The only difference is that the output is brought out on a flying lead - included in the installation kit.

Installation Instructions and Notes

Note: Although some of the documents below, and the pictures you will see at the bottom of the page, show a coax connection from the rig into the PAT board, I recommend that you use a short length of fine single wire (eg wire-wrap type or similar), as this will have a lower capacitive loading on any tuned circuits that may be affected by the tap. The PAT board should be located as close as possible to the tap point, preferably within 50mm.

Links to Instructions and Examples

G4HUP Link
External Link
FT450FT450mostly Italian!
FT1000FT1000K8AC  VE3TMT
IC706 Mk2IC706 Mk2M1BXF
IC756 Pro IIIIC756 Pro III
TS450/690TS450 and 690

Hardware Kits available

For the future, only the Generic Socket, Generic Plug and TS2k kits will be available - as specific varities run out they will be removed from this list.

Second Receiver Function

In addition to giving you a panoramic display centred on your Rx tuning, PAT can also be used to give a wider view as an independent second Rx. The input signal for PAT needs to be picked up before the 1st mixer, and your SDR must be tuned to the frequency/band you are receiving, instead of the IF frequency of your radio!. Operation is different, in that the SDR display will no longer change as you tune the band - it will remain fixed, and you can demodulate any signal seen on the SDR. Of course, if you wish to work a station, then you must net your Tx with the SDR Rx! See pictures below of 2nd Rx operation.

You can only have one PAT operating as an IF buffer OR 2nd Rx, not both simultaneously!

However, you can put two PAT's into a rig - one as an IF tap, connected after the first IF filter, and the second connected before the first mixer as a 2nd independent Rx. You can then either use a switched input single SDR, or two separate permanently connected SDR's on the outputs. I have done this with an FT897.

So to summarise:


This version has no LPF installed, so I've called it the Vanilla version! It is therefore ideally suited to 2nd Rx functions on radios which have VHF and UHF bands on them, such as the Yaesu 817/847/857 and 897 series. The radios all use a common 1st IF, which means that picking up the tap point just before the first mixer gives you access to the RF signal on all bands that the radio covers. This is more difficult on those radios that do not use a common 1st IF, such as the Kenwood and Icom all band offerings.

PAT 30M and PAT146M

These two new models allow direct connection of the output of your transverter to your external SDR, so for VHF and above users there is no need to go inside your favourite rig! Simply connect the PAT 30M or PAT146M in parallel with your IF receiver input, and see what is happening on your SDR.

Kits and built units now available.


To install this board, you need to open up your radio and make connections to the signal path and power supplies. You also need to either install a connector or route a cable out through the rear panel.

This may invalidate any warranty on your radio, and no liability is accepted by G4HUP for any damage caused while installing or operating this product in your rig. Installation instructions and notes are provided to the best of my knowledge and in good faith.

PAT installed in FT897
Panoramic display via PAT (40m) on TS2000 using 2nd IF (10.695MHz)

PAT installed in FT817 - output via rear panel SMA connector
PAT installed in TS2000

10m band data segment via FT817 and PAT - 60kHz view
20m band ssb segment via FT817 and PAT - 60kHz view

10m band CW segment via TS2000 and PAT - 50kHz view

20m band CW segment via FT897 and PAT - 30kHz view

PAT installed in TS440S
20m band CW segment via TS440S and PAT - 50kHz view centered on 14021kHz

New!! - Independent Second Receiver Function

30m band shown as a second Rx Function

40m band display using FCD Pro+ and SDRSHARP

PAT70M installed in Alinco DX SR8T (thanks WW4N)

Here's a link to a video of the system in use thanks to

WW4N is receiving using an RTL-2832U Dongle with GQRX running on Ubuntu Linux 14.04LTS
PAT50M installed in Yaesu FT840 (thanks AA4IO)

Page Created 15 Oct 13

Page Last Updated 4 Mar 2016