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Wednesday, September 29, 2021

N2CQR (WN2QHL) Novice Station Re-Created

 
There it is.  The 2021 re-creation of the WN2QHL Novice Amateur Radio Station.  This is what I had when I first went on the air in April 1973 from Congers, NY. 

-- I got my first Lafayette receiver (WITH JEWELED MOVEMENTS!) for Christmas in 1972.  My mom drove all the way into New Jersey to get it for me. 

-- I bought my first DX-40 and the Globe VFO Deluxe from someone in the Crystal Radio Club.

For this re-creation station: 

-- I got this recently acquired Lafayette free-for-pickup from a very kind SWL in the Shenandoah valley.  (I've discussed this receiver extensively here.) 

-- The DX-40 is the result of a couple of junkers that I bought in a hamfest some 23 or 24 years ago.  It might have been the Timonium Hamfest.  I cannabalized one of them and made one good DX-40 out of the two.  Parts of the cannabalized unit carry on the good fight as pieces of my balanced  antenna tuner (the coils were useful there) and as the chassis for my first SSB transmitter. 

-- The Globe VFO Deluxe was harder to recover.  There are just not a lot of these things around.  I actually put up a plea for one of these on the SolderSmoke blog.  Not even the IBEW could come up with one of these things.  But then, last week on Facebook I came across a fellow who was selling one.  Deal!  Check our the nice Juliano Blue light indicating 40 meter operation. 

Putting these three devices together was more challenging than I thought.  To get them to work together decently three different things had to happen as the result of throwing one switch: 

1) Antenna had to switch from receiver to transmitter. 
2) Receiver had to be largely muted (leaving some key-down signal for sidetone).  
3) VFO had to be turned on (I left it running and just keyed the DX-40).  

Fortunately I have almost 50 years more experience than I did when I first set this station up.  So I was able to do this better in 2020 than I did in 1973.   I had a 3PDT relay that I had built for a DX-60 station.  I was able to use it to do all three things described above. 

Muting the Lafayette was a bit tricky.  On the back octal connector they have two post  (1 and 3) that are normally connected.  Disconnecting 1 from 3 completely mutes the receiver by cutting off a needed ground connection to the RF amplifier and to an IF amplifier.  The Lafayette manual tells you to connect these terminals to the "muting voltage" presented by your transmitter.  The DX-40 doesn't have such a voltage, and I was reluctant to connect any voltage to this terminal for fear of blowing up the RF and IF amplifiers.  I figured that just putting a big resistor across 1 and 3 would mostly mute the receiver.  The 3PDT relay shorts this resistor on receive, un-muting the receiver. I use a 500,000 ohm resistor.  It works well, but the sidetone is chirpy while the actual signal is not.  This is a bit annoying. 

I re-capped the DX-40 when I got it back in the late 90's.  Those caps are still good. 

The Globe VFO had also been recapped.  But it still has selenium rectifiers in there.  I will change them ASAP.  Also, the Globe VFO had a somewhat mysterious second transformer in there.  I wondered what that was.  I measured the output:  6.3 V.  That is a filament transformer.  My guess is that the filament winding in the main transformer went open, maybe as a tube failed. Instead of replacing the whole transformer, they just popped in a replacement filament transformer.  That's fine. 

I've been on the air with this rig, mostly on 40, as I was as a Novice.   I can work anyone I hear on 40 meter CW and my CQ's are heard in Europe (as shown by the RBN). 

I'm struck by how physically BIG these pieces of gear are.  Much bigger than our beloved BITXs. 

Regarding T/R switching:   There was a line in the 1973 ARRL Radio Amateurs Handbook that really got to me back in 1973:  Page 640, in the chapter entitled "Assembling A Station:" "

"In any amateur station worthy of the name, it should be necessary to throw no more than one switch to go from the 'receive' to the 'transmit' condition." 

By this standard, my station was probably unworthy of the name.  I don't remember how I handled T/R changeover, VFO keying, receiver muting and sidetone,  but it almost certainly involved throwing more than one switch.  But now, I am happy to report, my novice station is finally up to the ARRL's high standards.  As Pete says, "When you know stuff you can do stuff." 

8 comments:

  1. Bill, I heard you this past Monday while I was killing some time in near-north Ontario. Heard your CQ and then someone answered you before I could. I thought your DX-40 sounded great and that VFO was doing the job fine... CW note sounded good and not even 'vintage' IMHO (a compliment). I keep an ear out for 'tube' sounding stations, but yours defied the search criteria. Have a great time this coming season with the shack warmers.

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  2. Wow, thanks so much for the on-the-air Ontario signal report! 73 Bill

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  3. On that mysterious added filament transformer in the VFO; perhaps it is wired ahead of the power switch in order to always keep the filaments on in order to decrease warm-up drift?

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  4. Cool idea John, but I don't think so -- the box is cold with power off, and there are no signs of glowing filaments.

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  5. My novice station was a Hallicrafters SX-99/U with an outboard Heathkit Q-Multiplier. The transmitter was a borrowed Knight Kit T-60. I accomplished my T/R switchover with a Dow Key relay. No sidetone, of course, so I really had to pay attention to my sending on the Radio Shack straight key I had.

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  6. Bill, your novice station looks good. I made a jumper using a phone plug to connect the key jack on the back of the VFO to the NO contacts on the the Dow Key relay. (Fig A, pg 8 of the V-10 manual) to place the VFO in standby during receive. I think that works better than keying the VFO and transmitter both at the same time as it reduces any tendency to chirp.

    I meant to change out the selenium rectifiers but never got around to it. 73 de WD4SCZ

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  7. Hey, thanks Emil for commenting (and for the VFO!). Yea, that is pretty much what I did with the VFO, except I did it with an ordinary 3PDT relay. I have the VFO on all the time when on transmit, and I just key the transmitter. Like you say, it reduces chirp. 73 Bill

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  8. Hi Bill what is your normal operating times there?

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