VHF FM transmiter... PLL LCD callsign

I make no absolute question in having my callsign displayed in the LCD of the PLL, first because it wasn't me who had the hard work making the software and credit must be given to the one (PY2EAJ) who did it and second just because all I want is it to work!
Anyhow Euclides (PY2EAJ) was kind enough to provide us (me and CT5JZX) the software sources, so, I ,had some time and exercised a little of my knowledge in assembly (I only programed so far the x86 family, and a long time ago). Since assembly languages are all similar, on to the business of replacing Euclides callsign for mine.
Initialy I translate Euclides callsign to Hex and then searched for the occurrence of it, which gave me the following code:


;; 197 : hd44780="P" hd44780="U" hd44780="2" hd44780="X"
movlw H'50'
call _11498__vector
movlw H'55'
call _11498__vector
movlw H'32'
call _11498__vector
movlw H'58'
call _11498__vector

;; 198 : hd44780="J" hd44780="E" hd44780=" " hd44780="R" hd44780="X"
movlw H'4A'
call _11498__vector
movlw H'45'

Euclides hex callsign is: 50 55 32 58 4A 45
Them I replaced for my own call in Hex (see the movlw instruction):

;; 197 : hd44780="C" hd44780="T" hd44780="2" hd44780="G"
movlw H'43'
call _11498__vector
movlw H'54'
call _11498__vector
movlw H'32'
call _11498__vector
movlw H'47'
call _11498__vector

;; 198 : hd44780="Q" hd44780="V" hd44780=" " hd44780="R" hd44780="X"
movlw H'51'
call _11498__vector
movlw H'56'
call _11498__vector

Well, that is it....for now... but we still need to generate new "hex" for the pic. That's easy in Linux just issue the following command:

gpasm lc72131-ct2gqv.asm

Where lc72131-ct2gqv.asm is the changed source file

Then you get for free the following files :)

lc72131-ct2gqv.cod
lc72131-ct2gqv.hex
lc72131-ct2gqv.lst

We only need the "hex" one. Now let's clean the PIC "internals":

picprog --pic /dev/ttyS1 --erase --burn

And burn the new code in it:

picprog --input-hexfile lc72131-ct2gqv.hex --pic /dev/ttyS1 --burn

No errors? Nice! I ended up with this on the display:




....We asked the wrong code to Euclides, should have been the transmit one and not the rx with 10.7 offset.....

p.s. Euclides was kind enough to send the tx code and also his new transceiver design based on the MC3362 and the LC72131 PLL. I've got mine almost finish but will send it to Pedro (CT5JZX) maybe he will test, he has a MC3362 for testing.

VHF FM transmiter... PLL PCB tests

After almost completing the PLL board assembly it was time for some testing.
I still don't have the push buttons connected and there's still missing the 4.5Mhz crystall for the LC72131 IC but anyhow decided to go with an 4Mhz just for seeing some progress. It's mandatory to use the 4.5Mhz (or 7.2) one as per LC72131 datasheet but for the PIC with exception for timers it's just a clock and a 4Mhz will do.



There were some connections missing int the PCB board due to abbreviation in the original artwork (power supply capacitors and LCD control pins), but no problem, components were connected in the cooper side.



It was also needed to put the LC72131 in the cooper side due the fact that this IC doesn't came in standard DIP22 but DIP22S, I guess the "S" is for short....



The display reads lock but no VFO connected so this is probably due the fact of the 4Mhz crystal is connected to the LC72131 instead of a 4.5Mhz one, or wrong connections between the IC and the PIC. Latter on when the VFO is connected I will investigate further. Without the PIC code it's impossible to know at the moment.

Original schematic artwork and software at: http://rf.w2c.com.br/PllLC72131.aspx
Very detailed buildup at: http://py2ohh.w2c.com.br/trx/2mpll/2mpll.htm
PCB design by: CT5JZX
The assembly mess by: CT2GQV (that's me)

p.s. maybe you prefer your own call sign in the LCD... then send an email to PU2XJE maybe he can arrange that for you.... or search for:

movlw 0x50
movlw 0x55
movlw 0x32
movlw 0x58
movlw 0x4a
movlw 0x45

....I just recalled, that last time I wrote similar instructions was in 1995 :)

FV-107 fixed crystal frequency

...Today it rained!

You may ask what that has to do with amateur radio...well first I don't recall last time I saw rain, probably in July, second it means the temperature will drop a little bit and it will be possible for me to do some soldering in the shack! That's the importance of rain...and of course I can stop watering my coriander plantation, the rain will do that for me :)



Continuing, as you probably know I have an FV-107, it's an external VFO for the FT-107 Yaesu transceiver but it's being used (connected) in my FT-102 with an adaptation circuit I made, the schematic and article available somewhere in this blog: (http://speakyssb.blogspot.com/2009/09/external-vfo-controller-for-ft-102.html)

The FV-107 VFO has provision for 6 fixed crystal operation. For crystal value selection you need to know your operation frequency, get a table provided by Yaesu (taking in account IF frequency scheme) make some calc's and then you have the VFO or crystal frequency, alternately you can put the radio in the frequency you want and measure the VFO output frequency, not very elegant solution....

Since I want to calc several frequencies and it's a repetitive boring task I made a small PHP online program that gives me instantly the needed crystal frequency and made it available for everyone to use, here's an usage example:
http://www.osprompt.com/ct2gqv/apps/fv-107.php?f=14200&m=usb
In the above example the frequency (f=) is 14200Khz and the mode (m=) is USB. The result VFO crystal will be 5248.5Khz. It can calculate for LSB/USB,AM and CW modes (use lsb our usb or amcw in the parameters), AM and CW have the same carrier frequency. 10m band isn't inserted in the programed frequency table just because it wasn't provided in the manual and I didn't use it. 17m band wasn't also in the manual but I calculated the IF values for the band.

Unfortunately it's difficult to find crystals in the range 5-5.5Mhz so for now my VFO will stay working as a true VFO :)

Light dimmer

Now for something completely unusual in this blog, I present the _incandescent_ light bulb dimmer (just in case you try to use this on a fluorescent bulb...).

How it all started: My parents bough a table lamp made in in the other side of the globe. Off course many products made there, maybe because of sea transport, have many faults on arrival :P. Well in fact I think it only worked for 1 minute before exploding in smoke, so on to me for repair, typical! The initial circuit was of so low quality and lousy components that I decided to rebuild the bloody thing, including the power cable.
Some time later here's the finished product now much more dependable and expecting a long life...

and the schematic:



The tricac is a BT138 that I had since 1988 (probably last time I build something like this), the diac is a BR100 and the potentiometer is 100k in value. Observe capacitor voltage ratings if your going to duplicate this... at least 400v just in case...

Should work for controlling the soldering iron temperature but my iron problem is not excess temperature.. :) so will not build one for me. By the way, bough another 250g solder roll, I think it's the second one this year...

Updates on the VHF transceiver

Some progress in the VHF FM transceiver....well...it's more like a receiver and transmitter in the same box.

Only commented the transmitter part, the receiver I already did that in some older post.
Just after the following photo I remembered that I still needed the frequency control...

..already done 3 holes between tone selector and mic gain...

Another photo:

Manhattan-style pad tool

After some unsuccessful tests trying to build one tool to make Manhattan-style pads I decided to buy one that I found at the hardware shop. Normally my pads are build square shape with the hack saw, not elegant and for sure not easy to make and also labor intensive, so, this is something welcomed to the tool box.
here are some preliminary results:



Although the toll is 10mm diameter the effective cooper pad (the one starting to drill on the cooper side) is 7.5mm in diameter. The tool is made for cutting holes in tiles but for sure fiber glass and thin cooper are no match for the "diamond" bits in the tool. Let's hope it last long since it's a bit on the expensive side, around 15 Eur.
I think I will exchange this one for the 8mm drill bit, for making even smaller pads.

Manufacteur is "Wolfcraft" from Germany (were else?!) and you can see specs here, in the manufacteur web site: http://www.wolfcraft.de/jcatalog_generated/en/products/product_groups/17618_product.html

Now here some progress on the VHF FM transmiter front panel:


Still need the holes for the TX led, MIC gain, Mic input and tone selector. Only the LCD and LCD contrast adjust drilled so far.

VHF FM transmiter... PLL PCB

Got this in the mail:



It was sent to me by CT5JZX who took care of ordering them. He is also making one for his own use. I opted for a PCB and not my normal method since I got the LCD and board for the same price of the LCD cost in the local electronics shop....and my callsign is stamped in the board :)

Now I must program the PIC and find (buy) the LC72131. Will also cut the unnecessary parts of the board since I don't think there's room in the master board to accommodate this one.

The schematic and "software" is from: PY2EAJ, Euclides, and you can see more at: http://rf.w2c.com.br/PllLC72131.aspx
and also here: http://py2ohh.w2c.com.br/trx/2mpll/2mpll.htm
with some description in English.