Antenna experiments

I’ve been planning for a while now to put up an antenna in the garden, but where is the question. I have a 20m wire and 9:1 unun to set up somewhere – ideally I’ll run this up the garden but that goes under the phone line, or actually the end of the wire would be under it. What stopped me was the impending changes for EMF as the unun would be mounted outside pretty close to our bedroom window.

So, for a laugh I got another unun to experiment with (yes I know I can make one but the ferrite I had is lost in the workshop moves). Looking at the ‘ideal wire length’ chart 36 feet comes close enough to the distance between the bedroom/shack and the hedge so I cut 36 feet of bell wire and launched it across the utility room towards the workshop as a measure. Tied to the bedroom window reached almost to the far side of the workshop. I reckon I can attach a pole there and attach the unun to the wall outside the shack – there is a convenient airbrick nearby. But, for a laugh I attached said bell wire to the unun, hung the unun on the window handle, ran about 6m of RG58 across to the tuner and tuned it up. The YT-1200 actually managed it right down to 80m (the loft fan dipole will not go longer that 40m).

But the FT450D was very unhappy trying to feed power in to any band under 20m. A string of clip-on ferrites cured that and I managed to be heard on FT8 in Eire and Germany on 80m plus managing FT8 contacts on 40m and 30m.

It is deaf – no surprises there. The bell wire is not taught so it almost touches the garage roof on the way down. A proper bit of wire stretched up may be better and I have a reel so more fiddling may be had yet.

The icing on this experiment was being heard, FT8 again in Finland on 60m and later managed an exchange with a French station – my first ever anything on 60m. Oh, yes, and I have that ‘Hold Tx Freq’ checked so it doesn’t stray outside our limits… worth remembering that because had it tracked up to the French station it would be out of our rage.

The downside is its getting very cold in the shack with the window open! 

FT450D MARS modification

In preparation for me receiving a full callsign (having just passed the full licence exam – yay!) I wanted to get the FT450D ready for 60m. Out of the box it comes with several pre-set frequencies that do not cover the available band slots and so the only recourse is to perform the MARS modification to the radio (aka ‘widebanding’). I uploaded the latest firmware first (v 244). Note that the firmware upload resets all the various settings so in my case I had to wind the power back down, set the CAT baud rate, and set the data type (‘D Type’) to USB.

I found two different sets of instructions on the Web, one referring to jumper JP4002 but another had a different number. However, one page had photos as well which tied in with what I could see. The instructions there are clear and are what I followed, the URL is

Following those instructions I took photos of each stage and have added a few notes below. Note that you do any modifications at your own risk and very probably voiding any warranty – I believe Yaesu will carry this modification out for you but this is just from what I ave read on the Web which may well be fake news!

The top and bottom cover need to be removed because you need to remove the front panel and this is held by the case screws. Each has 8 screws, 4 at the sides and 4 on top (or bottom). Note that the speaker is on the top cover and attached by a lead and plug to the front panel.

It was at this point that I got rid of the fluff which was everywhere!

The front panel is removed by easing off the 4 tabs that clip to the screw holes that can be seen at the bottom of each photo above. However, there is a ribbon cable that needs to be carefully removed – I found that it pulls out of the socket relatively easily (and went back similarly so). The socket can be seen on the right of the photo below.

There is a screen that needs to be removed in order to access the control board – this is in the radio and accessible after the front panel is removed. 6 screws hold it in place and I used a magnetised screwdriver here so as not to lose the things.

The photo above shows the control board. The front panel ribbon cable is to the left. The jumpers of interest are to the right of the largest chip. In my case the jumpers are all 0 ohm SMD resistors.

The instructions are to remove jumper JP4002. However, the labels do not actually seem to be next to the jumpers but given the photo on the other website I removed the same one, as seen above. has a very helpful photo with tweezers pointing at the right one.

It was then just a matter of putting it all back together, remembering to carefully push the ribbon cable back into the front panel, and carefully easing the tab back into place to hold the panel to the body. Oh yes and not forgetting the speaker lead!

The next step requires some dexterity. One needs to press the IPO/ATT, NB and AGC buttons together and keep them pressed while turning the radio on. My method was rather crude, holding the radio with my left hand thumb above the power button, pressing each of the three buttons above making sure each clicked, then turning on with my thumb. The radio powered up and displayed SMADJO. Note that the photos below are each what happened in my case and I have no way to know if other radios show something different.

Next, you rotate the DSP/SEL knob counterclockwise until TYPE appears. No need to press the knob in first. I have no idea what ’38’ indicates.

Now press the F key briefly, just a quick click. This will be indicated by the usual F being displayed. The instructions do not show what the ‘c’ indicates, but see below as this changes.

Then, press NB – again just a click. The upper left segment of the currently illuminated frequency digit lights, changing it from a ‘c’ to a ‘t’.

The final step is to press and hold the F key for at least 3 seconds after which there will be a long bleep and the radio will reboot. This is, at least how it worked for me.

One final note. The websites I found list the modification as 1.8 to 30MHz and I was worried that it may somehow knock out 50MHz – but it still works, in my case anyway! In fact, the radio now seems to tune from 0 right up to 56MHz but not cleanly. I found that tuning from 29.999 took it back to 29 unless the MHz step is set (by pressing Dsp/Sel and rotating to select MHz) one can get to 32.999. Pressing Band to get to 50MHz permits tuning, again via the MHz selection, from 33 to 56MHz. YMMV!



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