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Cables and connectors for connection between the PK-232 / PK-900 TNC and Yaesu FT-847 for HF / VHF

PK-232 - HF Cables

PK-232 - VHF Cables

PK-900 - HF Cables

There are a few issues to be aware of. In the case of using the Data port in the FT-847, there is a hang time on the PTT that is too long for Packet QSO's to be viable. I posted a message in the Packet Radio Forum that I belong to and another user of the FT-847 had the same issues and resorted to the Front Mic Connector, and rear Ext Speaker for the connection. That started to look a bit of a cable nightmare when dealing with all the other cables I have here. I had a bit of a google around and fell upon a note in a SuperControl.de page about long changeover on the FT-847 and there was another way.

The note said that some people had good results with using a 100nF (0.1uF) capacitor or 200nF (0.2 uF), so I set about trimming off all the nice neat heatshrink that I'd put on when making the cable up. Replacement of the capacitor for a 100nF has speeded up the transfer to one that will now support AX-25 Packet.

Anyway, I learned so you don't have to. You can either build the cable as I have below or experiment with a different capacitor value. There are also notes elsewhere that say to up the resistor to a 2.7k Ohm one but there is little explanation of why.

FT-847 Data Connector for HF Digital Modes

The FT-847 uses a 3.5mm stereo jack for HF digital signals, and therefore is fairly easy to connect to a TNC. The difficulty with the PK-232 is the lack of TNC connectors, if you are not lucky to get cables with your TNC. I didn't with any of my TNC purchases, so looked around in the supplies boxes and USB 5-pin Motherboard headers work just fine. These are wired to a small piece of strip board to populate the Capacitor/Resistor circuit to provide PTT, as designated by the Yaesu Radio User Manual.

The cables need to be at least shielded and wired to provide good ground connections between the TNC and Radio, else ground loops will give poor signals, transmit and receive. I have used JY-8022 Audio Cable (Twin shielded cable, in 8-form), Neutrik 3.5mm Jack and a homebrew TNC connector.

Parts

JY-8022 Twin Audio Shielded Cable
2k Ohm 1/4 watt Resistor
10 uF Electrolytic Capacitor - SEE ABOVE NOTE FIRST
5 pin Female Dupont Connector
REAN Stereo NYS231BG-LL Extra large entry 3.5mm Mini Jack plug

Assembly

Connect as diagram with 3.5mm Jack TRS ;

Tip - Signal T
Ring - Signal R
Sleeve - Ground

Connect Veroboard as circuit diagram ;

PK-232 TNC connector ;

Pin 1 - RX Audio = Signal R
Pin 2 - TX Audio = Signal T
Pin 3 - N/C
Pin 4 - Gnd = Ground
Pin 5 - PTT = Via Veroboard circuit
 

AEA pin-out for PK-232

FT-847 Data Connector for VHF Digital Modes

The Yaesu FT-847 has two connections for data modes, one for HF data and one for VHF/FM Packet. I detail the HF Data connector to the Pakratt 232 TNC on another page, and this page concerns the VHF/FM connector. This is a 6 pin DIN presentation, in a very small DIN configuration.

This connector, as you can see from the Yaesu diagram below has two speeds, 1200 and 9600 bps. This is indicated on the diagram for the cable ;

Wiring diagram

Yaesu Manual Pin-out for PKT port on FT-847

FT-847 Data Connector for HF Digital Modes on PK-900 

Parts

JY-1199 4 core shielded audio cable
5 pin Female Dupont Connector
5 pin Mini-DIN Connector

Assembly

Wire as circuit diagram, ensure shield provides continuity between Gnd and 5 pin Mini-DIN Connector to prevent ground loops and hum.

After the PK-232, I wanted a PK-900 but AEA PK-900 is a rare sight. I found one on E-Bay with only 6 mins left to go. I promptly bid and won so now have one of the best TNC devices made. The connection cable below is for the HF Data port on the FT-847 to the PK-900 using the same cables as for the other PK-232 cables on this site.

Parts

REAN Stereo NYS231BG-LL Extra large entry 3.5mm Mini Jack plug
JY-8022 Twin Audio Shielded Cable
2k Ohm 1/4 watt Resistor
10 uF Electrolytic Capacitor - SEE ABOVE NOTE FIRST
5 pin DIN Connector

Wiring Diagram

Having an MD-200A8X, I rarely need to look at other audio sources. Combined with the majority of radio time these days being on digital modes, I have not had the need to buy additional kit, until now.

Like most of the planet, 2020 didn't really go to plan and I was working from home and replacing endless video conferences and meetings in the office with Microsoft Teams and Amazon Chime calls. Quite frankly the audio on these calls is awful, with a mixture of cheap tinny mic's in laptops and the odd cheap, or sometimes expensive headset that doesn't really represent the voice of the person very well, and being USB isn't terribly useful for anything else. The additional fact that any reasonably priced headset has long gone and is on back order, I thought I'd have something I can use on the radio when I'm back at the office, instead of getting lost in a box somewhere.

I didn't find a cable diagram for a Yaesu 8-pin to XLR cable so have put the following information together in the hope it helps someone else get their BPHS-1 on the air a bit quicker than I did.

I've also added all the homebrew cables I make for my outboard audio connections.

(Yaesu 8-pin) > (XLR) for Headset Direct

(Mixer) > (Attenuator) > (Yaesu) for Xenyx Mixer into Radio.

(XLR) >  (Isolator) > (Attenuator) > (Yaesu RCA) for audio isolated connection from Behringer Mixer to Radio.

(Yaesu 8-pin) > (RCA Socket) Breakout cable for front mic socket for cable above.

Audio-Technica BPHS-1 direct to Front panel Yaesu 8-pin

The following cable is a alternative to the Heil CC1-XLR-Y8BAL cable, without the PTT in this case, but can be easily added. I've not seen one of these cables to comment on the build quality or anything within the wiring that may be better or worse ? This one works well though, and costs about £5 + your time.

Yaesu 8-pin to XLR

• Neutrik XLR Female Connector
• Yaesu 8-pin Connector
• 2 core plus shield cable
• Heat shrink (preferably not red, it's all I had in that size that was accessible)

Yaesu 8-pin end connections

Pin 8 - Signal +
Pin 7 - Signal -

Route shield to the plug casing by clamping the shield back through the connector. Test for continuity whilst mobilising the cable to ensure good contact.

PTT can be added by placing a switch, or two pole connector between pins 6 (ptt) and 5 (gnd). There have been reports that this can lead to RF breaking into the cable thus I didn't add this feature.

XLR end connections

Pin 1 - Shield that is connected to the 8-pin connector body.
Pin 2 - Signal +
Pin 3 - Signal -

Place wire between XLR connector ground and XLR pin 1.

Note: Disregard the capacitor in the following pictures. This was to prevent RF noise, but it actually created a filter on the audio chain ! Removed in final implementation.

Test shield continuity between XLR Pin 1 and the 8-pin connector body.

Base of connector showing Shield to Connector ground (excuse the soldering on test connector, still works though)

Top of connector, showing capacitor and top of ground loop. (This soldering is even worse, still works though)

 FT-2000 Mic Gain setting - 85, but this may change when the EQ is set up.

Behringer Mixer Output to Yaesu Rear connector (incorporating Line to Mic Level Attenuator - -40dB)

This cable is a 6.35mm mono cable from the mixer to the rear Phono mic connection into the FT-2000. This is expecting a mic level input, whereas the output of the mixer is Line level. A -40db attenuation is required, so a L-pad is created from 2 resistors to drop to a 10th of the originating signal. This should level the microphone input.

In this case, an already terminated cable was purchased, with a Neutrik barrel connector, which has plenty of room inside to hide away two resistors and a capacitor, with careful soldering and heat shrinking.

The final solution is an L-Pad with an 680 Ohm and 68K Ohm resistor, as follows ;

Why a 680 Ohm resistor for the output, well that is the input impedance of the mic connector on the back of the Yaesu FT-2000.

This forms the Pad part of the homebrew isolation box between the Outboard Audio equipment.

This cable did introduce some hum in testing, but I had poor grounding, so Your Mileage May Vary with this, but as the next cable is so easy to make, I'd go for that anyway. 

Isolation and Attenuation

It's not that I didn't want to buy a W2IHY i-box, but I had some bits and pieces and I enjoyed the challenge of building all my other cables. I'm not claiming that my implementation is better, but it was a product of experimentation, which for me is what Amateur Radio is all about, and why I got a licence in the first place.

The basic implementation presents the basic functions of Attenuation and Isolation. The circuit gives -35db attenuation which results in the FT-2000 Mic Gain being 29 with the Behringer Mixer set at 0db on the main output, +4db from the line.

The main purpose for this circuit is to attenuate the signal from the Mixer to the front end of the radio. (Via the Mic port in the rear of the FT-2000, Mic Socket on the FT-847) Isolation between the Radio and the Audio kit, and reduce some Hum and RF being passed into the audio was also a requirement.

The Transformer is rated between 100 Hz to 15 KHz, but may swap it out for something better in time, or re-engineer a DI box. 

A note for the FT-2000, the rear port is live with the front port in the menu settings. There should be no need to change anything for the rear port if you are using the front one currently. Both Mic ports are also live, so a mic without PTT will also provide input if you have a mic in the front as well as the rear.

Completed Cable Assembly

8-Pin to RCA Extension Cable  (For above) 

The Weather in Combe Raleigh in 2019

After the hot summer of 2018, there were the beginnings of another warm, dry summer for 2019 but that all fell apart in June with 20 rain days. As I sit compiling the data in the first days of January 2020, already 3 days have been +3^oC on the long term average.

After the events of 2018, I didn’t have the time or capacity to compile the weather records for the year. I have included the data for both years, hopefully it is not too confusing. 

2019 brought us 1053.6mm of annual rainfall, which is an increase of 78.2mm or approx. 3 inches from 2018, at 975.4 mm. In 2019, we experienced 199 days where it rained more than 0.2mm, in 2018 it was 184 days. The wettest 2019 month by volume was December, with 166.6 mm where it rained ( > 0.2mm) for 21 days, with the wettest day being the 18^th with 24.8 mm. The driest month in 2019 was May, with 9 rain days and 20.6 mm. The Met Office yearly average for SW England was 1403.0 mm (2018 was 1265.8 mm) and 168 days (2018 was 149) where it rained more than 1 mm. (Note the differing rain day parameter)

Our temperatures were actually up from last year, with the yearly average temperature rising to 10.9°C, from 10.7 °C in 2018. The Met Office yearly average for SW England was 10.4 °C (2018 was 10.5° C).

Over the 2019 year, temperature data recorded 44 days above 22°C, with 1 day dropping below -5°C (3^rd Feb). In 2018, that was 55 days above 22°C, with 2 days dropping below -5°C (28^th Feb, 1^st March).

The lowest recorded 2019 temperature recorded was -6.3°C on 3^rd February, at 7:55 am. The highest recorded 2019 temperature was 29.1°C on 25th July at 2:30pm.

In 2018, lowest recorded temperature recorded was -6.0°C on 1^st March, at 12:59 am. The highest recorded temperature was 29.9°C on 8th July at 3:49 pm.

In 2019, we had no Ice Days recorded (days where the temp did not rise above 0°C). 2018 experienced 3 Ice Days (28^th Feb, 1^st March, 18^th March). 

May and July were the peak months for sunshine hours, with an annual total of 1011.4 Hrs. 965.6 hrs recorded for 2018.

Station reliability has been fairly good this year, although an intermittent fault with the Anemometer in November resulted in no wind speed readings. I didn’t have time to climb on the roof to take a look, and then it came back by itself. I’d better inspect when the weather gets better or it stops again ! There is also a solar power fault on the Soil and Leaf wetness sensors, which I hope to fix soon but requires some soldering and replacement components.

In 2020, the computer hardware that runs the weather station will be replaced and the website updated as it’s been running since we moved in 2012 without much change apart from the odd reboot. Please contact me if you’d like to see how everything is connected up and how all this data is recorded, displayed on the internet and shared for research purposes.

Summary daily data – 2019 (2018)

Number of days where …

Max. Temp. exceeded/equalled 22 °C was 44 (55)

Max. Temp. was lower than 0 °C (Ice day) was 0 (3)

Min. Temp. was lower than -5 °C was 1 (2)

Precipitation exceeded/equalled 0.2mm was 199 (184)

Precipitation exceeded/equalled 2.5mm was 102 (105)

 Frost Days – 47 (46) – (days where the air temp was lower than 0 °C at any point.)

Recorded weather data

Average temperature          = 10.9°C (10.7°C)

Average humidity                            = 85% (79%) 

Average dew point              = 7.2°C (5.7°C)

Average barometer              = 1016.5 mb (1014.7 mb)

Average wind speed          = 6.0 mph (7.6 mph)

Average gust speed             = 11.0 mph (13.5 mph)

Average direction                            = 200° SSW (60° ENE)

Rainfall for year                               = 1053.6 mm   (975.4 mm)

Maximum rain per minute             = 1.4 mm/min on 9^th August at 3.31 am (1.0 mm/min on 30^th July at 5:27 pm)

Maximum temperature       = 29.1°C on 25th August at 3:40pm (29.9°C on 8^th July at 3:49 pm)

Minimum temperature       = -6.3°C on 3^rd February, at 7:55 am (-6.0°C on 1^st March, at 12:59 am)

Maximum pressure            = 1044.4 mb on 4^th January at 7:50 pm (1039.6 mb on 4^th September at 7:50 pm)

Minimum pressure             = 967.8 mb on day 3^rd December at 00:00 am (982.4 mb on 3^rd March at 00:00 am)

Maximum wind speed       = 59.8 mph 86°( E ) on 12^th March at 7:12 am  (59.8 mph 188°( S ) on 28^th November at 1:53 pm)

Maximum gust speed        = 96.6 mph 272°( W ) on 15^th March at 12:39 pm (98.9 mph 146°(SE) on 12^th October at 9:37 pm)

Maximum UV Index             = 8.9 on 1^st July (7.2 on 21^st July)

Maximum Solar                    = 1315 W²m on 1^st July   (1165 W²m on 17^th August)

Maximum Sunshine Hours             = 10.9 hrs on 22nd June (10.8 hrs on 28^th June)

Total Sunshine Hours                     = 1011.4 hrs (965.6 hrs)

Comparing with an average across the 8 years we have been recording weather here in Combe Raleigh, the following table shows how 2019 compared;