Universal CAT and programming USB to serial TTL interface for ham radio

Скраћена веза: https://pedja.supurovic.net/veza/9536

Some years ago I posted article describing Universal CAT and programming USB to RS232 TTL interface for ham radio that I made.

Here is small update, adapter for YAESU FT-8900, FT-8800 and alike radios.

FT-8900 and FT-8800 and some other Yaesu radios use two wire interface. One wire is ground and other is both RX and TX. This is also known as CIV-I interface used in Icom radios.

CIV-I interface is quite simple. There is a diode (universal like 1N14148) connecting RX and TX, oriented cathode toward TX, with one 10K pull up resistor to 5V on RX. […]
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Vectronics PM-30 SWR/Power Meter User Manual and Schematics

Скраћена веза: https://pedja.supurovic.net/veza/9510

I’ve got second hand Vectronics PM-30 SWR/Power Meter and found out very little information about it on Internet. I’ve prepared Manual and Schematics from paper documentation I got with it.

If someone needs it, here is download: Vectronics PM 30 pwr swr meter manual and schematics

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Baofeng UV-B5 / UV-B6 enhancing modulation

Скраћена веза: https://pedja.supurovic.net/veza/8998

One of the issues of UV-B5 is that it has shallow modulation when passing through some repeater systems. That is common issue with Chinese radios. R4HV posted on YouTube explanation how to fix that. As his post is in Russian language it does not popup easily on search sites.

However, modulation fix is rather simple: one resistor has to be removed and new connection made using 150 K resistor . That is all. Check his video.

 

Here are pictures before and after the modification:

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Spiderpole 12m anchoring construction

Скраћена веза: https://pedja.supurovic.net/veza/8741

Spiderpole 12m made by Spiderbeam is very useful for portable ham radio activities. To do the job it must be properly anchored. This pole may be anchored at the bottom (at about height of the first element) which allows it to withstand wind speed of abut 80 km/h, and at 7 meters high using guying lines (as recommended by manufacturer) which allows surviving windows of 120 km/h.

Anchoring at the bottom seems not suitable for portable, as it requires either to have already set strong short pole (fence or something) to attach pole, or dig one into the ground. […]
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Dunax GPN-4B antenna construction details

Скраћена веза: https://pedja.supurovic.net/veza/8733

After few years of sitting on top of my apartment building I decided to bring my Dunax GPN-4B antenna down for repair as top capacitive hat was broken. I found out that there actually no technical details about fixing it. So I went through some work of gathering such information.

First I found out that manufacturer is out of business. Antenna is not in production any more and manufacturer site is down. I asked help from fellow hams, some sent me some info they had, some sent me contact info for manufacturer.I also used my own antenna to take measurements, so finally I got quite complete details that I believe could help other fellow hams trying to repair their own antennas but also ones that want to build similar antenna. […]
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Build grid dip meter adapter coil for antenna analyzer

Скраћена веза: https://pedja.supurovic.net/veza/8706

Antenna analyzer like MFJ-259, MFJ-225, MiniVNA and similar may be used as simple grid dip meter for measuring coils, traps and capacitors. All you need is grid dip meter adapter coil which you may buy (costs for MFJ adapter set is about 30 USD) or make it by yourself for few USD.

If you want to build on your own here are dimensions of original coils sold by MFJ.

Small coil for short wave frequencies: coil diameter 15mm, coil length 15mm, 30 turns of 0.5 mm copper wire wound on PVC tube. Coil inductance should be about 3.6μH. […]
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