some activity

It has been a long time since the last entry. Ham radio activity is limited at the moment.

One of my small projects the small projects is a 137 KHz  /500 KHz generator. I have a old 27 MHz transceiver that was stripped for parts. It is still working though. I have wired it to transmit continuously.
I plan to make a digital signal out of it. Then it can be divided digitally to get 137 KHz and 500 Khz.
This can be done by small module inside the CB radio.

wire through pulley

I have a small mast with a 2m/70cm antenna on top of it. On top of the mast a pulley is mounted. It is used to keep a wire antenna in the air. This wire antenna was connected to a non conducting wire. Unfortunately the isolated wire broke so my antenna came down.

I already mounted the wire to the top of my chimney. However I want to use the pulley for a different antenna. So I had to find a way to get a wire through the pulley again.

Last night I succeeded. I took a 2 meter long tube. I pushed home electricity wire through that tube and through the pulley. When enhough wire was pushed through I connected isolated wire to the electricity cable. Then I pulled back the tube with the wire. This pulled the isolated wire through the pulley.

ic730 rx preamplifier relay problem

One of the know problems with the good old IC-730 is a non working preamplifier relay. The relay does switch but no difference in signal level is heard. The problem is dirty contacts in the relay. I found some solutions on the internet. I suppose they work but I did something more simple.
-remove transparent plastic hat of relay. Do it gently it looks like it can break easily
-turn on radio
-turn of preamp
-put some wodka/alcohol on a piece of paper. between the contacts
-turn on preamp
-gently move paper around.
-turn off preamp
-remove paper
-mount plastic hat

I have cleaned it this way 1.5 years ago, the preamp works without problems since.By the way, when using a 2x13 meter dipole antenna the preamp is not needed at all. Not even on 10 meter. When the antenna is connected the noise increases significantly.

500 KHz and 137 KHz

Hopefully we get an allocation around 500 KHz. It seems to be an interesting band. At the moment a few hams are permitted to use 500 KHz on a temporary base. I was too late to apply for a license.

Nevertheless I start building an synthesizer for 500 KHz and 137 KHz. When it is ready I can use it for a 137 KHz transmitter. And hopefully for a 500 KHz TX too.
What I have here is a PLL synthesizer that works from 5 MHz to 5.5 MHz. It has TTL output. It was intended for a HF transceiver project. It works but it produces to much phase noise for a receiver. For a transmitter it is good enough though. Especially when when frequency is divided.

For 500 KHz Dividing is done in 2 steps. First divide by 5 then by 2. The divide by 2produces a signal with 50% duty cycle. That is important for the power amplifier.

For 137 KHz the divided by 5 signal is divided by 8.

I made a small print for the dividers. It works, the signals sound good on a HF receiver. A picture will follow soon.

160 meter

I received my 160 meter CW signal on websdr twente.The signal was not strong S7. Maybe the new antenna layout helped. The test was performed in the middle of the night using 80 Watts. It must have been skywave propagation as the distance is over 120 km.
Now I hope to make some contacts on 160 meter.

Transmitter using tuner

At a flea market I bought an old PLL tuner. I wanted to know if the synthesizer could be used for hamradio. It had to be an old one as the new ones use a everything on on chip approach. I suppose the synthesizer is unreachable in the new tuners.

Plan was to use the synthesizer for the FM band. Mix this signal with a signal out of a VXO at 98.7 MHz. then filter it using a lowpass filter at 20 MHz. This would make a 0-20 Mhz signal generator. I listened to the signal of the synthesizer in cw mode to check the quality. Unfortunately It does not sound like a T9 signal.

I also listened to the signals out of the medium wave synthesizer. This signal sounds T9. The synthesizer can generate a signal in the 160 Meter band. Stepzize is 9Khz. I could make a AM transmitter just for fun.

fixed antenna

One of my trees had grown into the wire dipole antenna. It had a big effect on the antenna especially during rainfall. So I cut some of the branches. Unfortunately one of the support wires broke. It turned out that the weather had weakened it. I could pull it apart by hand easily.

So I climbed upon the roof to connect the wire antenna to the chimney. I suppose the antenna works beter now. Previously 4 meter of the wire ran parallel to the metal VHF/UHF antenna pole. That is not ideal. I did not make a qso using the new setup. So I don't know how it performs. I did found out that the antenna tuner needs different settings.