Welcome to the G6OHM Website


Capacitor Conversion Chart

Useful Stuff

 2M and 70CM  R , S ,RB , SU  Conversion List


 A few years ago the powers that be decided to rename the band plan for 2m and 70cm.

A lot of amateurs including myself always knew the channels as R , S , RB and SU numbers.

Looking the other way around the new novice licensee would not understand the old listing. 

So i have made up lists to help the old and new amateur with the numbers.

Please feel free to copy these lists and i would be interested if you are using them on any novice courses.


 Resistor Colour Coding Help


CTCSS Tones Used in UK

Coax Loss Calculator

PL259 , N & BNC Type plug Assembly and Soldering.

I have decided to do this section as i am amazed at the amount of radio amateurs that cannot or don't like fitting plugs to coax. They will pay lots of money to buy a 10m length of coax with plugs fitted.

First thing is get a high wattage soldering iron or solder gun rated about 100w.



I have seen lots of people trying to solder a PL259 with a small iron. I's not man enough for the Job.

Also use the correct solder. The new stuff is like bird muck !.

I use 60-40 resin solder. You can get this from Tool Station.

Link to Tool Staion

Always make sure when soldering your plugs etc they are clean .

Scrape the section you want to solder .This helps the solder  stick to the metal.


Here below are sheets to help you fit your connectors correctly.



                      Small Coax PL259 With or Without Reducer


                                          Large Coax PL259 Assembly




                  Assembly of Small Coax Pressure Sleeve N Type Plug




                 Assembly of  Large Coax Pressure Sleeve N Type Plug


 If you are still unsure how to make up a N Type plug for large coax take a look at the link below.

Assembly of N type plug


  Assembly of BNC Plugs


OK that's the correct way to do your plugs and i know there's a quick and method of doing PL259 Plugs.

I will put my hand up and say yes i do the quick method. 


Fitting a PL259 Plug : Quick and Dirty method:

This method can have it's problems.But if fitted well will work.

 The problem doing this method is as the shielding braid does not get soldered , over time, corrosion can cause a resistance between the braid and the plug body which can result in a degradation of incoming signal and, possibly, damage to the transmitters output circuit due to high VSWR

  1. Cut back outer insulation by 30mm.
  2. Cut back braid leaving 6mm.
  3. Cut back center core insulation leaving 10mm.
  4. Fold back remaining braid over the outside of the outer insulation.
  5. Twist center wire so that no strands of wire are loose.
  6. Insert the cable into the plug and screw the braid into the threaded section at the rear of the plug.
  7. Solder the center core wire at the tip and cut off excess.

    I am going to put my hand up and say yes i use this method.

Over the years i have had the odd problem, but nothing serious.

With this method if you want to reuse or remake the plug  you can.



                         Making up Compressiom PL259 Plugs









 Also has anyone converted a BNOS amp to 70mhz ? Again please get in touch.



Back in the 1980's  BNOS Electronics  started producing equipment for the amateur market.

The equipment was very well made and i personally feel it was far better made than Microwave Modules Equipment.  This is my own opinion !

Information on BNOS Equipment is very scarce so i am trying to gather information on this equipment.

Here below is adverts that were seen in the magazines around 1984






                            BNOS produced a range of Low Pass  Filters.


                         Information on Filters Supplied by Trevor G8KNJ






Here is the operating instructions for the BNOS 2M amplifiers  




 Pictures of the BNOS 12/6 Power Supply   pictures by Kelvin Munson



                                                 Picture supplied by David G3ZPF


                                      Picture supplied by David G3ZPF



                                            Information supplied by David G3ZPF




                                                Circuit diagram of BNOS 12 / 25 Power Supply

                                                          Circuit supplied by  Graham G1PEU





BNOS 6M Amplifier Operating Instructions . Info from Hugh G6CTP




 70CM 3- 50W 432MHZ Amplifier


                                                                      PICTURE BY DAVE 2E0ADO

                                                            PICTURE BY DAVE 2E0ADO


144 MHZ 10-100 AMPLIFIER


                                                         PICTURE BY ANDY G6OHM


                                                                PICTURE BY ANDY G6OHM



                                             BNOS LP50-10-50 Simon  2E0IAF /OZ9SP





                                  4M Amplifier  LPM70-10-100 picture by Dave Remnant M0SAT


 BNOS Transverters






                         Been sent some info by Steve G6AOS on a BNOS amplifier used for PMR frequencies.



 Makers spec:-
455 to 465 MHz
5w input / 100w output
13.8volts @ 22amps
Amplifier in class AB

Note:- no RX preamp fitted no provision on pcb ( but room to retrofit preamp in unit if needed)

Unit is the same size as the bnos high power BNOS linear.

Info:- A , 2 stage amplifier
With pcb layout for a 'Pre Driver stage - not fitted.

With both RF sensing and hard switching facilities.

1x mrf648 single ended driver stage
Driveing 2x mrf648 in push pull
(Matched pair) - rr02 code

Broadband  linear (in class A/B)
With coaxial input & output transformers 10 MHz bandwidth)
With relay switching tohtsu CX 140D coax output relay.


BNOS Transverters


Radio Programming


One part of the radio hobby i enjoy is programming radio's.

A lot of radio amateurs buy a new  radio and think that everything is programmed up for them.

They get the radio home plug it in and suddenly realize they cannot work there local repeater because it needs the CTCSS setting up , the repeater shift altering or the radio needs to be set on narrow deviation.

They try to adjust the radio and get frustrated with it. The rig ends up being used on a simplex frequency or gets put in the cupboard and forgotten about.

What a waste of a good radio !

The software i use is written by G4HFQ. Bob produces some excellent software for a number of the Yaesu range of mobile ,shack in a box and handheld radio's.

To obtain the software go to Bobs site at the bottom of the page.Down load it.You then pay for it and Bob send you a code you type into the program this then opens the program up fully.

Here's a picture of the FT7800  main programming page. The program vary slightly from rig to rig.

 Each Yaesu radio has its own software apart from the Yaesu FT817,FT857,FT897,FT847.

You will also need a programming lead.These can be obtained off EBAY for a reasonable cost.

Next you need to get information to program the radio like repeater frequency ,CTCSS tone frequency, wide/narrow deviation, repeater shift.


This can be obtained from UKREPEATERS.NET  

 click here

 Go to the home page and then go to the  Band Occupancy section.


  Click on the bands you want.

Write down the information for the repeaters in your area.

Next read your radio by clicking on Read FT7800 or what ever radio it is.

Follow the onscreen instructions.

If all is well it should have read your rigs information.

Save the information to file 

Save again and call it something different like YOUR "CALLSIGN EDIT "


Save again . Open the file callsignedit and enter the information from uk repeaters site.

rx frequency,tx frequency, CTCSS, repeater shift, name of repeater etc etc.

Once you have entered all information in save to file.


Click on Write FT7800 or whatever radio it is.

Follow the onscreen instructions.


If all is well the file should have wrote to your radio.

You now should have a rig that works the repeater around you.


But if did not write for some reason.This could be you have a modified rig.Try changing the rig type number.

It could be you are using a USB lead ( i find USB to be a real pain so i use comport 9 pin plug types.

Check out G4HFQ website this will help sort out problems.


G4HFQ Website

 Another good free programming software is Chirp.

 Chirp Website



 I do get asked to program other rigs, like Baofengs, Anytones, Yaesu's, Kenwoods

This is only for the East Anglian Area. 

Please email me if you need my help. Email link on the home page.


KE4RX Cheetsheets