Monday, August 15, 2011

Should I or shouldn't I?

Thanks to the latest blog post from John AE5X I have the web page for a new QRP kit open in another browser tab and the pointer keeps hovering over the Buy Now button. The kit in question is the TJ2A, a two-band handheld SSB/CW transceiver for the 20m and 40m bands that has just been produced by YouKits of China.

Regular readers of my blog will know of my fondness for handheld radios. I'm finding this one very hard to resist even though I have an FT-817 and so no need for another handheld 20m/40m radio. At this point in my life I'm not even sure if building it is still within my capabilities. If I did try, it would be the most difficult kit I have attempted since my Elecraft K2, and I built that 12 years ago when my eyes were a lot sharper and I was not suffering the after effects of a brain operation. Should I or shouldn't I?

The TJ2A looks like an updated and improved version of the Mizuho HF handhelds that were produced during the late 1970s which still fetch a tidy sum whenever they change hands on eBay. Like the Mizuhos, the TJ2A is VXO controlled and covers a portion of each of the two bands, though you can install alternative crystals if you would prefer to have full coverage of one band in two ranges. You could also choose other bands by changing the VXO crystal and bandpass filters.

The building instructions are on the web and it looks as if the kit uses mostly through hole components but there are some SMD transistors. It isn't perfect. There is mention of warm-up drift in the first 5 minutes after switching on or changing bands. There is also a mod already to stop BFO leakthrough into the IF stages. And there doesn't appear to be any high SWR protection for the PA so using the rig with handheld antennas - or any type of antenna that presents a mismatch prior to tune-up - might be problematic.

But it looks really cute. And it's a kit. There are few things in ham radio more rewarding than hearing the first signals, then making the first contact, on a radio you built yourself. Should I or shouldn't I?

14 comments:

Henrik said...

Hello.

I have found a pre built version on Ebay if you don't feel like/can assemble it yourself.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=270759398517&ssPageName=STRK:MEWAX:IT#ht_2335wt_905

//Henrik SA4AER

Anonymous said...

Julian, one of the things that prevents me from buying it is that, although it's a dual mode (CW & SSB) rig, its freq coverage essentially makes it a single mode rig.

You have to choose whether you want the VFO to cover the CW *or* the phone portion of the bands - it won't do both without realignment.

John AE5X

Julian Moss said...

I think you can opt to have one full band in two segments. It's an issue of the limited VXO range and only having two XOs available.

Casey Bahr said...

Yes, that's what the manual states, that you can cover an entire band (non-WARC) in two ranges. So, it's dual mode in one band. Not sure if you can cover both the CW portion of one band and SSB portion of another?

Julian Moss said...

The built version Henrik found will cover the CW end of 40m and the SSB end of 20m unless you specify otherwise, if you check that eBay listing. So it would seem to be possible.

sv3auw said...

My advice is, don't buy it.
The rig is under development and YouKits is doing so by asking for F/B.
You are going to evaluate the kit and you will pay for it!!!

Julian Moss said...

Like I did with the K3, you mean?

sv3auw said...

You can't compare the TJ2A with K3.
As for K3 it was a matter of new firmware.
How about the TJ2A?
If someone is advertize his products/Kits and his cooperations, in radio magazines all over the place, he must be able to support his kits on his own.
I am not going to sent him my FB not to buy the kit at the first place!

Ed de la Rie // PE5ED said...

go for it !

Richard G3CWI said...

There is already one for sale on my Flea Market. Advert offers swap for FT817... Must be a hopeful seller!

73

Richard
G3CWI

ianmorris1960 said...

Julian,

Its worth a go, I don't have the cash at the moment, but when I do that is a must.

Having just recovered from a similar, but nowhere near as serious a condition as yourself, I found the bitx great therapy!

Ian
G8OWB

W7CJD said...

Crystal package No.1:
There are 5 crystals in this package, covering below frequencies.

1) 40M 7.090Mhz - 7.165Mhz CW SSB Extra Advanced only (USA)
2) 20M 14.175Mhz - 14.325Mhz SSB
3) 17M 18.068Mhz - 18.160Mhz CW SSB
4) 15M 21.360Mhz - 21.438Mhz SSB
5) 10M 29.550Mhz - 29.600Mhz SSB

Crystal package No.2:
There are 7 crystals in this package, covering below frequencies.
1) 160M 1.992Mhz - 2.000Mhz SSB
2) 80M 3.987Mhz - 3.997Mhz SSB
3) 60M 5.320Mhz - 5.410Mhz SSB
4) 40M 7.248Mhz - 7.298Mhz SSB
5) 20M 14.228Mhz - 14.350Mhz SSB
6) 12M 24.910Mhz - 24.979Mhz CW SSB
7) 10M 28.326Mhz - 28.420Mhz SSB

G4ILO

"There is also a mod already to stop BFO leakthrough into the IF stages."

Is that online?

"And there doesn't appear to be any high SWR protection for the PA so using the rig with handheld antennas - or any type of antenna that presents a mismatch prior to tune-up - might be problematic."

I was thinking a Hendricks SLT+ built-in the compartment for the battery pack and use precut End-Fed Half Wave wire antennas.

Maybe an Emtech ZM-2 built-in "ugly construction" style?

W7CJD

W7CJD said...

Here is the mod:

www.youkits.com/TJ2A/tj2a%200603%20Schematic.pdf (June 3, 2011)

www.youkits.com/TJ2A/tj2a%20handheldProtel%20Schematic.pdf (May 27, 2011)

Here are the dimensions: 20CM x 7.5CM x 4.5CM

I would like to know what are the inside dimensions of the battery compartment?

onno becker hof said...

Hi Julian,

The unit is end of sale and a few months ago I bought one of the last units. As others mentioned it was a kit under construction. I had to change a couple of things to get the unit to work. Almost there and looking forward to the first field day:-) regarding the frequency range I received different crystals per request and my band coverage is fine. Second, with a small change you can double the frequency range without loosing stability. Right now the vxo utilizes an inductor to lower the vxo frequency and a variable capacitor to increase the frequency... making the inductor switchable will allow the vxo to work at higher frequency... cheers, onno de pa1ap