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

http://www.yaesu.ru/instruction/FT-1907R.pdf

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?

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.

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.

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?

The ANYTONE 5189 4M FM Mobile

Martin Lynch and Son have taken delivery of their first batch of the new ANYTONE 5189 Transceivers. These cover 4M and output is about 40 Watts on high power. I think the specification is 60 watts so some internal tinkering may be considered in the future? That said the 20 watts difference is not great and probably won´t make a difference on the air.The radio come nicely packaged with a double fused power lead, fist microphone, mobile mount and of course a fairly easy to read manual. The manufacturer is Qixiang Electronics (Never heard of them!)
I have only just bought this today (24th November), one of the initial batch of ten. Initial on the air testing has been positive.
It has a very large integrated heat sink. I imagine that this can actually dissipate the power on 60 watts.



The rig is a little sensitive to SWR, changing the coax length by 1/4 wavelength resulted in just shy of 40 watts out.

I took a few photos of the display, with and without the flash. As you can see its not huge, but acceptable for mobile use. Still no S meter...sigh!

Tuning of the VFO is on the front panel dial (Finally no more up down buttons!). The dial doubles for volume if you press it once. The squelch is on a menu (Can´t have em all....) but can be defeated by a button press for those DX contacts?

On the air reports were good although the default deviation of 25Khz was too wide and had to be turned down to 12.5K

Sensitivity was slightly better than my ASCOM SE550 and the integral speaker was very clear and produced good audio. the microphone is a good size and comes with up/down buttons for mobile use. It connects to the rig using the RJ45 type connector, similar to most modern rigs.

There is a speaker jack at the rear.

This is one of the first batch and the next batch should be in before Christmas. At £149.95 they aren´t giving them away but if you compare it to the Yaesu FT-2900 single band 2M transceiver its not too expensive and hand helds aside the only new 4M transceiver available on the market (So put it on your Christmas list now?)

6M band pass filter

I recently lost the 6M front end transistor in my FT-897D. This is a tiny SM transistor nestled in the middle of the PA board.

I can't be sure if this was due to early failure of the component (The 897 was only a month old) or a stray RF field from my HF or other VHF transmitters. Initially I looked for a replacement transistor. I found out its a Japanese part (Doh!!) and although there are equivalents available the original part is only available from Japan. I gave up and went back to Martin Lynch & Son who had the part (and a competent technician to fit it).

Very soon they put the magic factory smoke back in my FT-897D (They did it while I waited) and while I waited I thought about ways keep it in there. I decided on a two prong approach -
- Fit a low pass filter on my HF amplifier
- fit a bandpass filter on my 6m station

Prong one was reasonably easy. Fitting a good quality low pass filter on my HF station was a good move and fairly easy. It helped reduce TVI and other unwanted nasties although my neighbors TV still dies if I TX on 12M. I assume that must be something directly unacceptable in his set to 24mhz as I have fitted an HF choke and 6M stub in his down lead. Maybe I will try a 24Mhz stub as well...

Anyway the 6M bandpass filter proved to be more tricky. I ordered one from ICE but after a few months nothing arrived and no reply to my emails (no charge on my card either) so I gave up on that avenue. I was looking through the ARRL Handbook and found a reasonable design for a 6m bandpass filter and decided to build that. I also downloaded the original article from 1968 QST as my membership of the ARRL gives me access to their archives (Are you listening RSGB?) The article gave a little more detail on construction such as doubling up the air spaced capacitors to achieve the 100+ pf required.

It took me about a month to scrape together all the bits (Enclosure, caps , copper line etc) but eventually I felt ready to build the filter. I could procrastinate no further.

It took a Saturday to complete the project. To ensure the comb lines were properly connected to the enclosure I cut it from a single sheet of copper and sandwiched it to the rear using a strip of aluminum (an off-cut from the Maplin box I had to cut down) fixing it all in place with about 15 4M brass nuts and bolts and washers..

I found that the filter worked very well but was far narrower than I expected. The article said it should be reasonably flat across about 4Mhz. Mine was about 300Khz wide... I could live with about 1.5Mhz as the UK 6M band is only 2Mhz wide and I never go above 51.34 (local repeater) so I started to explore what was wrong.

I had built the filter from 26awg sheet and the design used this may have had a small effect but I didn't think it would make that much difference?

It was suggested by G4MDC that to improve the bandwidth I would need to increase the coupling between the comb lines. Rather than pull the whole thing apart I tagged copper strips over the existing lines. This thickened the combs and increased the coupling.

The finished filter was still quite narrow (about 900Khz ) but its easier to tune and with a Maplin knob fitted to the central tuning capacitor I can easily adjust the filter to center on the FM (51.34Mhz) or SSB (50.15mhz) frequencies.

I'm still a little baffled by the design. Did the original filter cover 4Mhz as claimed? Had anyone else built this in anger?

that said I can now run full legal on 6m with not a spot of interference (The filter really does handle QRO as claimed) and so far my front end transistor hasn't blown again!

A budget LCR meter

It seemed to good to be true, but so far the LCR meter I bought on eBay appears to have been excellent value at only £12.98 (including delivery!!!) - Yes you heard me right!

I have been looking to buy an LCR meter for some time. One use I intended for it was to replace the variable capacitors in my HB9CV antennas with fixed capacitors (Made of PTFE coax). that only requires a comparison but being able to measure is always a plus point!

Having placed my order on eBbay I awaited delivery. The eBay shop was in HK so I wasn't expecting fast delivery. It arrived within the week which was very quick and costing only £12.98 (including delivery)it didn't attract VAT or import duty.

I have added some shots of the unit which came with battery included.
All the instructions are in Chineese (maybe I should get them translated) although its pretty self explanatory.

The meter came with a set of leads which I decided against using. Instead I purchased some croc clips and mounted them on some old 4mm posts.. that gave me a nice set of short leads and an easy way to secure components whilst testing.

It seems reasonably accurate across the range but I'm a bit skeptical about the 2000Mohm range (I don't think I have a 2KMeg ohm resistor to test it....).

It even has an internal lamp for the display!


If you want a cheap and cheerful LCR meter this seems as good as any other. I will do some further testing and comparison at the local club....

Oh yes it comes with a transistor tester as well.