Saturday, February 25, 2017

Simple antenna switch - DIY

Necessity is the mother of invention, so today's post showing how to do some recycling and change junk stuff into quite usable thing. 
Working on HF with more than one antenna, or better to say, using radio with single antenna connector is always complicated. Things get worse when You need to switch to some other antenna HERE and NOW, and of course there's always lack of any switch. Recent dx-peditions VP6EU or TX5T are the examples :-) 

We will use ferrite circulator salvaged from Telecom equipment. This will give us perfect enclosure, 3-4 SO-239 sockets, piece of silvered wire and old ceramic junk switch. 
Overall costs - not more than 15-20 Euro, few hours time, including painting. 

This is our base - soon it will switch 2 antennas with more than 500W RF power.

After removing unusable parts, 3 holes were drilled to fit SO-239 sockets

Some painting to get neat look, and sockets installed :

Time for switching part

To ensure that 500W will not harm the switch we need to cross both connector sides with silvered 1,5mm diameter wire :
 No worries about the lenght of connections, it's not microwave device ;-) 

Just add a knob and suitable labels on top and the switch is ready for use :

Tested at solid 500W while hunting for TX5T, measurements done with two 50Ohm terminator shows SWR 1:1,05 on HF bands up to 50MHz. 

Have fun with your own DIY switch ! 


Friday, February 17, 2017

Warning! Ham radio addicted YL in shack ;-)

It's very good when You can have another ham radio operator in family, even better when your Lady run's ham radio at such level of involvement. One of the lucky guy is Maciej SQ6RMA :-)

Friday afternoon started with cup of coffee with YL Halina, better known as SQ6PLH, keen and addicted contest operator on HF and SIX meters, and of course YL of Maciej SQ6RMA.

If You did not heard SQ6PLH until now, You will for sure this season :-)

73 & 88 !


Tuesday, February 14, 2017

IC-7300 simple CW/SBB/RTTY memory banks keying MOD

Below is a simple IC-7300 stock Microphone HM-219 MOD for those who do Contests, DX pile-ups expeditions and lot's of CQ - all this without using external keyboard attached, disconnecting the Microphone and wasting your voice.

Modification is completely reversible, and almost cost nothing - all we need is only 2pcs of 1,5kOhm SMD 0402 size or just ordinary carbon film resistor 5% accuracy.
This will allow us to key two first banks of memory signed M1 and M2  

First open the case and locate copper track leading from switch DN through 470Ohm resistor to UP switch and down low the microphone PCB to output solder point - red wire.

First step is to replace existing 470Ohm resitor close to "DN" switch with 1,5kOhm SMD.

Next cut the trace from "UP" switch leading down to Red wire and remoce green mask for soldering second 1,5kOhm :

 Solder remaining resistor at the place, and after some cleaning - we are done.

Because UP/DWN switch using the same pin3 in Microphone plug, no resoldering is needed.
Now "UP" switch is acting like M1 bank and "DN" switch as bank M2

Shouting in pile up or run local Contest without wasting your throat or making your wife angry :-O
should be much easier now...


Friday, February 10, 2017

EY8 - Tajikistan QRV on 70MHz

For those who not aware, we will have another juicy DX on 70MHz to hunt for.
Following the news on DXNEWS.COM    this Year we can expect well known 6m operator Nodir EY8MM to be active on 70MHz from his home grid MM48FI.

 Map credit : DXAtlas

Approx distance 4100km from JO92 - looking good for 2 Es hops. 

At the time no information about antenna, but hope Nodir can put some Yagi before season.

GL all !