49’er & Fake Transistors
A recent posting to Yahoo's 'GQRP' reflector spurred discussion of the growing number of fake transistors being seen on e-bay. A builder enquired about the low efficiency noted in his recently built Chinese '49er' kit.I recently bought one of the Chinese Forty-9er transceiver kits off ebay and on receive it works well. It certainly transmits, but the power is down to 800mW and the driver transistor is getting very hot. I'm not expecting a lot of power from it, but power claims are 1.8W to 3W. I'm more concerned about the hot driver transistor. The following link shows the circuit diagram.
http://www.ebay.com/itm/DIY-kits-Frog-Sounds-HAM-Radio-QRP1-8W-CW-Transceiver-Receiver-7-023MHz-/121507448525
I've checked for spurious oscillation (a problem I've had before), but can find nothing. Does anyone have any ideas for why the transistor is getting hot?
It was suggested that the transistor in the PA may not be up to specs and even be a 'fake' as these types are commonly noted on e-bay, selling for prices that are too good to be true.
The problem was eventually sorted out by exchanging transistors:
Firstly, thanks for all your help. Initially, I replaced the Chinese PA transistor with a BD139 and that increased power output to 1.2W and reduced the heating of the driver. Key down and it took perhaps 20s to get "finger hot", rather than 10s. Tonight I changed the driver transistor to a 2N3904 as used in the original Forty-9er and the driver heating seems to have gone away. A small heatsink on the PA transistor allows it to run at 1.4W output for 30s of keydown without any drop in power or the heatsink getting any more than warm.
Thanks for all your help and I hope this helps someone else.
A search of Youtube videos shows several builders that have split some of the RF devices open in order to compare die sizes of suspected fakes with the real thing:
Earl Andrews, VE3GTC, has gone to considerable effort to test and compare many of his transistor purchases and indicates that there are a lot of devices coming out of China that are outright fakes and have no hope of meeting the specs that you might expect. His interesting website has a lot of details about testing as well as a very comprehensive 'for sale' list of reliable devices. Earl also suggests using caution when buying e-bay Chinese electrolytics as his measurements of ESR values indicate that many do not pass specs.
If you have purchased fakes or have found a Chinese source of the real thing, please let us know ... I'm sure there are plenty of dealers selling the real thing out there.
Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].
User Hostile! Radios that you love to hate!
“I hate this radio”
Have you ever said this?
I certainly have. Some radios are a joy to use. They are intuitive, easy to use and you don’t ‘NEED THE MANUAL’ every time you want to change something!
HT’s seem to be the most ‘user hostile’ radios available to hams. I know! All HT radios should have certain things, VFO, on off knob/button, volume control and keypad, and in my opinion, they should not be so difficult to use that you need to read the manual every time you want to do, what should be a simple task; change CTCSS tone of a repeater, for example!
When HT’s were reduced in size, they became more complicated to use. Menu systems were instituted. They were further reduced in size and menus were multi-layered! How many times have I yelled at my HT after holding button a for 1 second, then within 4 seconds, tried to press button 2, for 1 second but no more than 2.5 seconds, while doing 3 pirouette turns on my left foot, only then, can I use my radio. That same button has 3 functions now a days. Press it once for one thing, press it again within a specified number of seconds and you get another function. Press and hold it and you get yet another option.
Enter the English Translation, manual! Poorly translated from Japanese, but at least its in English! (With many pertinent things omitted!)
Why do manuals go to great lengths to tell you in great detail everything that you ‘don’t want to know’ and will most likely never use or use very seldom?
But tell you want you NEED TO KNOW, naw! Tell you how to ‘undo’ something? That would make it too easy!
Actually, I really like this VX5-R HT from Yaesu. It’s a love/hate relationship, however! So very handy, it fits in the palm of my hand, has lots of memories, and many many nice features. Accessing those features is not always easy, especially without the manual right in front of you. If you ever push the wrong button, and send it into ‘never-never-land’, its hard to un-do what you just did! One thing that was left out of the VX 5 is a memory clear feature! That omission makes life with this radio difficult at best!
You cannot return a designated memory channel to its ‘no data’ state. The only thing you can do from the radio itself is to overwrite that particular memory with another frequency!
I’m not picking only on Yaesu!
This Icom V 8000 is the most ‘User Hostile’ radio that I have ever owned.
Not only is it difficult to use, but it has problems as well. The mic is notorious for a mechanical problem with the PTT button, and the external speaker jack does not work well. Unfortunately, the external speaker jack is where you have to plug the programming cable in to program the radio. The Icom program for doing this is also ‘user hostile’ BTW!
Editing and Cloning Software RT Systems I bought software and cable from RT systems to program and manage the Icom T 70-A. The HT and its programming software arrived yesterday.
The Icom T-70-A, is the replacement radio for the Yaesu VX 5
It will replace the VX5 as my ‘go to’ HT. Just last night, I picked up the Yaesu VX5 the wrong way, mashed some buttons on its face and sent it into never-never-land! Try as I may, I could not undo it with normal button press. Since the radio has an RT Systems program and cable on its way, I went nuclear, and reset the processor. Finally, the radio was operational once more. It needs programming of course but the display is no longer stuck!
It programmed the Icom T 70-A radio to my specifications with only a cursory reading of the manual. The radio is intuitive, easy to use and has some great features. RT Systems Programming Software and Cable
Funny, I just installed an Icom 7100 mobile HF/VHF/UHF/MF radio in my truck. That radio was ‘done right’ by the manufacturer! Its easy to program and use, so there is no need to keep the manual handy for simple tasks. I run mobile CW/SSB and VHF repeaters with it. If there were any UHF in the area, I’d have that programmed in there too. Its a joy to use!
This photo shows the IC 7100 on a modified clip board held in place with bungee cords. So far, I have not seen the need for programming software. That said, there is an SD card on board this radio. It can save the settings to the SD card. I have not explored this avenue yet. It would be nice to keep a copy of the settings on an SD card and on my laptop for future use. Something unexpected can happen. Spare radio data would come in very handy then. Replacing all the settings would be very easy with the programming/clone software. RT systems sells that one too.
Do you have a radio that you love to hate?
Ernest Gregoire, AA1IK, is a regular contributor to AmateurRadio.com and writes from Florida, USA. Contact him at [email protected].
49m Canadians QSL’d
An e- mail report to long-time veri-signer and Ontario DX Association mainstay, Harold Sellers, brought a quick e-mail verification. I was hoping that CFVP would still be issuing a paper QSL but nowadays that is getting to be a rarer and rarer policy.
Harold also reports the following details about CFVP:
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| CFVP Tower courtesy: Harold Sellers |
Steve reports that CFRX is simulcasting CFRB (1010kHz) using 1000 watts into an omnidirectional vertical antenna. They have received several reports from Europe over the many years that he has been sending verifications.
Now to tackle CKZU!
Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].
ID-880H in the jeep
Michael Brown, KG9DW, is a regular contributor to AmateurRadio.com and writes from Illinois, USA. Contact him at [email protected].
ID-880H in the jeep
Michael Brown, KG9DW, is a regular contributor to AmateurRadio.com and writes from Illinois, USA. Contact him at [email protected].
10m BitX transceiver
I notice that someone has created a 10m (28MHz) version of the BitX transceiver. Yes, all would like more details but we don’t know who you are!
Anonymous said: “I have successfully designed and built a 28MHz version of the BITX transceiver. The main reason for this project was to drive homebrew transverters for 6, 4 and 2Metres. Contact me if you would like details.”
Roger Lapthorn, G3XBM, is a regular contributor to AmateurRadio.com and writes from Cambridge, England.
Fourbox transceiver
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| G7CKF’s Fourbox |
Jenny, G7CKF has now taken the 2m Fredbox design and created a 4m version called the “Fourbox”.
Hi Roger,
I feel I should drop you a line with my thanks and the link below, I’ve used your QRP AM transceivers as the basis for a 4M transceiver and published it on my blog. I’ve come back to amateur radio after a 20 year absence and since construction was always my main interest in the hobby I reached for the soldering iron.
http://thekeywordgeek.blogspot.co.uk/2015/05/a- transceiver-for-not-lot.html
There is no sparkling new insight to be had from it as it’s pretty much your fredbox with slightly bigger coils. There is no crystal because I am cheating and using a Raspberry Pi clock generator to make my 70.260MHz.
My QTH is IO91lw, between Bicester and Buckingham and rather low lying. Very little 4M activity hereabouts, sadly, so the chances of my actually working anyone with it are slim. But that’s not really the point of building, is it.
Anyway, hope you find it of interest, and thanks again for sharing your designs.Jenny, G7CKF
Roger Lapthorn, G3XBM, is a regular contributor to AmateurRadio.com and writes from Cambridge, England.






















