Sunday, August 18, 2013

MY 2M Station

I thought I would post my 2M station details.

I have owned the FT-225RD for a number of years. Its been quite modified but nothing that can't be reversed. These include

  • Mutek front end
  • Separate RX port 
  • External Amphenol relay for RX/TX switching
  • The microphone includes a home brew compressor to  improve performance slightly
  • Mods to quieten sideband noise of the VCO
  • External PTT sequencing to protect the relay contacts from the...
  • Tokyo Hy-power HL350Vdx which is a courtesy addition for those hard to reach DL and HB stations
The IC-202S is a recent nostalgic purchase. This was the first transceiver I owned back in the 70s and I remember the fun working GW for the first time HI HI. It had some "Issues" but their mainly sorted now. 

Tune up yielded 5 Watts once I adjusted the 2M band pass filter correctly (Bypassed on RX). The ALC works well throttling it back to 3 watts but I did notice some overshoot...

I plan to fit rechargeable batteries and take it portable. See you on 2m SSB? 



Friday, December 28, 2012

Round up 'em doggies

Happy 2013 to all, lets hope its a good one. 

I achieved a good end to 2012 by coming first place in the 2012 ARRL RTTY Roundup




Of course there weren't that many entrants for England but I was top. It looks like running up a good number of multipliers (running all bands and chasing continents/countries) paid off. Congratulations also to Mike K4GMH winning the single op category for NA, hes always a big signal and I often work him on all bands. The 2013 ARRL RTTY Roundup is next weekend so I will see if I can up my 2012 score and secure another win.

I built a reasonably good VHF station this year. FT-225RD + Mutek front end driving a Tokyo High Power VHF amp to 300 watts +

My 2M array seems to have gone faulty (I think it may be the splitter) so as soon as the high winds die down I'm going to make repairs. 





The 2 x 4 ele Cushcraft boomers work well but I think I will replace them with a single long yagi.  Probably another Boomer as they work so well.

I'm up to 159 countries confirmed on HF RTTY through LOTW so I hope the double century isn't too far off. Maybe 2013 will be the year?

Anyway, I may have a busy year at work but I'm sure I will see you all on HF RTTY over the weekends?





Wednesday, April 18, 2012

A word on fraud

It would appear someone is using my name and call G3VZL to advertise equipment and then defrauding purchasers. I'm not the first this has happened to or the last.

If you ever see an advertisement with my call only those with my email G8UBJ.IO91UJ(at) GMAIL.COM is a valid advertisement. BTW I very rarely advertise and if I do I invite viewing/testing at my QTH!

Unfortunately this sort of thing will happen and so long as people are stupid enough to -
1 Set up a website without sufficient security checking at registration

If you see an advertisement for Ham radio equipment check the seller is valid through another site like QRZ.COM and LOTW

Do not send money, please report this to the authorities.

VY 73 Rex G8UBJ

Saturday, January 21, 2012

The FT-1907R UHF Mobile

I  recently started looking for a UHF transceiver for the shack. I know its easy enough to buy something like the FT-8900 but I have separate antennas for each band & I really wanted something I could leave running. 
 

I thought Alinco were about the only company left selling single band UHF transceivers until I discovered the FT-1907R.
 As you can see its a companion to the FT-1900 2M transceiver from Yaesu.

I found a Greek company selling this on eBay which surprised me as its not listed on the Yaesu dot com site. Either way it was quite a reasonable price and delivery was quick.

Initial testing showed that it did provide 55 watts output as specified and on the air was reasonably sensitive. I'm sure that if this gets to the states we can rely on the ARRL to put it through its paces so I won't go further into testing as my facilities are limited.


Transmit and receive runs from 400 - 470 Mhz continuous.

At the heart of the The PA stage is Mitsubishi RF Mosfet module capable of 60 watts

 http://pdf1.alldatasheet.com/datasheet-pdf/view/169066/MITSUBISHI/RA60H4047M1.html

I found that like the FT-1900 this gets quite warm during extended transmit so I will publish a fan modification in my next post.

 As its a UHF rig an N-type connector would have been a nice addition. This was quickly fixed.

The rig comes with the usual Yaesu accessories (Even the sticky Yaesu label). I found the user guide listed on the Yaesu Russian site but strangely its only mention is on a brochure where it says Asian market only


I'm not sure why its not more widely available; maybe its early days or maybe Yaesu are trying to protect sales of their multi band transceivers in Europe and North America?

Friday, December 30, 2011

Look Mum no Hands, or - FSK without using an RS-232 port


In a recent QST (August 2011) I spotted an article showing a way to implement FSK keying using only the audio output from your PC.
The article was written by Doug Hall K4DSP who can take full credit for this brilliant design!

You can find more information on this project at - http://k4dsp.homeip.net/~doug/regenerator/


That may sound easy but up to now the only solutions that provides true FSK without using an RS232 port have required conversion from the USB port which is quite complex in order to achieve a stable 45.45 baud rate.

The FSKit from Doug converts transmit AFSK tones from your PC into FSK keying and also PTT. In addition it provides isolation between the PC and transceiver.

I wanted to build a portable station for field use using my IC-706 and a lap top PC (No RS232 ports) and I didn't want to use AFSK as -

1 - You have to keep an eye on the drive levels to ensure a clean signal
2 - The displayed frequency is incorrect 
3 - You need a work around to use the narrow RTTY filter.

The article from Doug was easy to follow; at the heart of the project was an AMTEL AVR micro-controller (ATTiny 45). The binary is available online but in reality it was easier to email Doug and purchase the micro-controller and at the same time a PCB...




The circuit was fairly easy to assemble although obtaining the op-amp and transistors required a little searching around.

I decided to house the FSKit in a Maplin enclosure and add a few bells and whistles..

1 - Powered from the IC-706 8v line
2 - Incorporate CI-V control for logging and spotting
3 - Some indicator lamps (Power - PTT - FSK - CI-V)
4 - Audio out gain control for transmit of PSK and other modes
5 - Audio in gain control  and isolation
6 - Audio transmit side tone  

I tried using an L78L05 to run the board but it was a little fussy a 3.3 volt regulator worked perfectly. The board uses very low current so the low power version is best.
 
I have a simple CI-V and tried an isolation circuit for this, unfortunately I couldn't get this to fly so just routed the CI-V through the terminal unit with some in-line ferrites to provide a little protection. 

All the indicators were LEDs - 
  • Power just needed a 1K resistor in series
  • PTT and FSK lines run to LEDs with a 2k and 1k resistor in series to the 3.3v line
  • CIV was a high brightness LED across the CI-V line with a 2k resistor in series (Flashes to showing active data present).
Doug provides an isolated audio output on his board. I fed this to a potentiometer and then on to the rig.

Audio receive was from the rig to another potentiometer and then an isolating transformer to the PC audio input - I use N1MM with MMTTY RTTY which uses audio in so just needed some isolation.
Last was a simple moving coil microphone insert that was across the audio input line. This is useful to check the tones sound okay on transmit and gives the operator confidence that something is happening (I find complete silence on transmit a little disconcerting.
As you can see the whole project went into an aluminum enclosure. I could have squeezed it into something smaller but the box I used made for an easy life.

The cable from the rig to the terminal terminates in a 9way D-type so I can make up other cables for other rigs in future. I used an old VGA cable as it has ferrites pre-installed and several screened conductors which are useful to keep the audio lines quiet.

I haven't labeled the terminal unit yet but that's the only thing left to do.

Its not a microHam interface but its inexpensive & does the job for /P operation.

I think this probably the best and least expensive way of implementing true FSK. I have made a few contacts from home but I'm looking forward to summer when I can try it portable.

Friday, September 23, 2011

I do desire we may be better strangers.

Or - "It was hard to code so it should be hard to use" 

Who would have thought eBay could implement a feaure thats so poorly thought through that I gave up on them. 

Their new "Shopping Basket" function has to be the worst thing. Worst still buyers can't opt out or remove it.

I'm sure some green horn functional analyst specd it out but I don't think the Product Owner tested it.

If you use the Bay be very careful with this feature (Totally avoid it if possible!) as it lacks controls to remove items and auto comitts you to purchases you don't want.

This sort of thing isn't rocket science, just pop over to Amazon and you can see how it should be done. Then again I don't suppose Amazon have the highest NPS scores by being careless.

Adios ebay - I do desire we may be better strangers.

P.S. Employing professional analysts with a web background may help you solve this problem.

Sunday, May 15, 2011

After 33 years of RTTY operating here are my 33 whys of RTTY ;o)

This rant is dedicated to Ted who thought I didn't Blog often enough!

  1. Why don't some RTTY stations insert a space at the end of their callsign so it doen't run into the following text?
  2. Why is there always an Italian or Ukranian calling CQ on the spot frequency of the DX you need?
  3. Why do stations running a split listen to every frequency but the one I call on?
  4. Why doesn't eveyone use unshift on space so I don't have to use mousover to decipher their serial numbers?
  5. Why don't any Nigerian stations use LOTW?
  6. Why can't I ever seem to work Utah or Delaware when Alaska and California are so easy?
  7. Why is RTTY on 14.08 21.08 28.08 and then 50.3?
  8. Why am I still waiting for my first country on 4M RTTY?
  9. Why can't some stations spot frequencies correctly i.e. carrier f0 = mark frquency?
  10. Why do some stations use AFSK and then compound the sin by using AFC?
  11. Why doesn't N1MM remember my comment for all spots when re-started?
  12. Why use 75baud RTTY when its 50% faster but 50% more errors?
  13. Why is PSK 31 and RTTY so mixed together on 10Mhz?
  14. RYRRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRYRR Why?
  15. Why are there only about two stations active in each African country except ZS?
  16. Why do some sations have strange shifts wider than 170Hz?
  17. Why can't some stations seem to net correctly?
  18. Why do I seem to miis the leading "I" when first tuning a station on 20M so I stop thinking its K6NNN when its only IK6NNN?
  19. Why are there more licenced hams in Japan than in the US?
  20. Why do some stations seem to have a line feed fetish (Didn't they ever run RTTY on a Teletype machine)?
  21. Why do conditions deteriorate exactly one minute before a contest starts?
  22. Why don't more stations run RTTY on Top Band (I only have seven countries confirmed)?
  23. Why do some stations stop transmitting at the end of their over with no CR LF?
  24. Why does RTTY rock and PSK suck?
  25. Why are all the finest hams on RTTY?
  26. Why is it called RTTY (Radio Teletype) and not RTTE?
  27. Why is there still no software for AMTOR when the available firmware is getting really ancient?
  28. Why isn't more RTTY/Ham software written for Linux distros (I'm tired of having to run Micro$oft Windoze in my shack)?
  29. Why don't contest organisers set operating frequency limits and exclude contacts (Or disqualify competitors) who go outside these limits to stop interference to other band users?
  30. Why do some Russian RTTY stations never copy you even when you run QRO?
  31. why do some RTTY stations sign/QRP when we already know how weak they are?
  32. Why are there only about four RTTY hams in China none of whom ever seem run more than a noodle for an antenna?
  33. Why do I enjoy RTTY operating so much?
WHY? WHY? WHY?