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...

GL! 

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 !

Tuesday, January 31, 2017

ICOM IC-7300 SSB average power MOD

If You are owner of 7300 this MOD should make You more happy looking on your small Icom 7300,
not to mention about saving your throat screaming loud to get more than 30W on SSB.
Quite dissapointing serious factory fooling their users saying that screwed ALC unit is made to comply with the high standards of spectrum purity and A class signal. 

So what about their other radios, i.e 746, 756 or any PRO series?  Are they piece of *&**(^&^ and should not be used? Kind of bullshit IMO.

At this point I need to pass my sincere KUDOS to Marios SV0CL for his priceless hints, discussion and help.    

Here's a solution - SSB average power (or "talk average power" ) increase MOD, born after hours spent on examining schematic diagrams, comparing circuit details and ham radio cooperation.

Likewise as in IC-7100 low average SSB power ( but not only SSB - i.e FSK441 and JT6M ) it's the problem of  too sharp ALC limiting making the ALC loop acting too fast to let the signal envelope to rise enough. And it's not the matter of MIC gain setting nor PROC value. As You probably seen on the video posted in December HERE difference in average SSB power is HUGE at first sight.
Take note that MIC gain and PROC settings remains LOW comparing to this what we can find on various websites concerning low power on SSB, and we are still within 75% of ALC scale!

WARNING : Any mistake can cause serious damage to your radio. So if You are not experienced in SMD soldering or using soldering iron at very FRAGILE enviroment - do not try to perform the operation! I will be not responsible for any damage You can make doing the MOD.    

 

We need to prepare tantallum capacitor, magnifying glasses, and a value of 2,2-4,7uF /16V will do the job for us. The bigger capacitance, the slower ALC rise time. Test proved that 3,3uF works well and could be optimal solution, but 4,7uF will be good as well.

This time we need to add the ALC slowdown capacitor here :


Although 7300 unit is almost the same as 7100, we can see few small changes, mainly in component values.
Apart of on MOSFET transistor added ( changed vs 7100) there's no difference.

IC-7100 ALC :

IC-7300 ALC :



Open your 7300 removing both covers, and face the radio left side to You. Having speaker on the right hand, on the left You will see RF UNIT. This is the place we will work.
Take very good magnifying glasses, we will solder our capacitor between VERY small SMD elements.
Look at the MAIN unit and locate region marked RED:


Closer look at PCB :

Gently bend the legs of capacitor at desired angle, and try if they fit between the soldering points between elements before soldering. 
And this is how it's look after adding the capacitor:


After soldering check the surface against any short circuit around tiny traces. 
Don't forget to clean the surface with amount of IPA alcohol or similar stuff and secure the capacitor to the top of  IC1501 with small piece of double sided adhesive tape, or single drop of nail enamel borrowed from your girlfriend or wife :-)

Final look :

 
Good luck with the mod. Please post the comment below if You'll do the mod with success.
If You feel You can't do the mod yourself, better ask a friend. 
Of course You can send the radio here, I'll do it for You.   

NOTE: 

I AM THE RIGHTS OWNER OF THIS DOCUMENT. 

ANY UNAUTHORIZED COPYING WITHOUT ASKING IS DENIED. 

IF YOU WANT TO PUBLISH THE MOD ON YOUR SITE/BLOG YOU ARE ALLOWED TO DO SO, POINTING THE ORIGINAL SOURCE. 

THANK YOU.  

 

Monday, January 23, 2017

No 70MHz in DL this Year :-(

Sadly, starting New Year with bad news coming all around.
One of these news is, we will miss DL stations on 4m again this year. What a pity!

Read more HERE (German)


Thursday, December 29, 2016

Finnaly arrived ;-) 4m Double Century MLA Award

Today finally got my first of Awards issued by IRTS - Irish Radio Transmitters Society.


Looking good, ready to printout from convenient pdf format file.
No fee's, Awards are free, all You need is only spreadsheet with QSO's/grids certified by local Award manager or two ham operators and send it to IRTS Award manager.

Read more at IRTS site  http://www.irts.ie/cgi/st.cgi?70mhz

Good luck!