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Harvey Wells TBS-50 Transmitter




 
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Author Topic: Harvey Wells TBS-50 Transmitter  (Read 6938 times)
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RolandSWL
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« on: September 30, 2014, 09:23:45 AM »

Hi All,

 What kind of antenna connector did this unit have?  I've seen a single standoff and a UHF type connector. Which is the original configuration?

 Thanks, Roland
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KA0HCP
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« Reply #1 on: September 30, 2014, 04:00:22 PM »

Single ceramic stand off.  Chassis ground is a zinc plated 6AWG screw with nut about 1.5 inches to the side.  Between is a stamped hole for adding an SO-239 (some early models may not have this).
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New callsign KA0HCP, ex-KB4QAA.  Relocated to Kansas in April 2019.
KA0HCP
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« Reply #2 on: September 30, 2014, 04:07:01 PM »

Here is a photo of one of my TBS-50D's, presently on the bench.


* Antenna Mt.JPG (1047.52 KB, 3072x2304 - viewed 463 times.)
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w1vtp
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« Reply #3 on: September 30, 2014, 05:17:02 PM »

Single ceramic stand off.  Chassis ground is a zinc plated 6AWG screw with nut about 1.5 inches to the side.  Between is a stamped hole for adding an SO-239 (some early models may not have this).

(Emphasis mine.)  That solves that mystery!   I don't think my aunt's TBS-50D had that SO-239.  She always had an end fed ant - at her house and at our house when she moved in.  That was a great entry-level transmitter that folks could get who either didn't have the funds or the desk space for a V1.  I think the going rate for eBay is way too high and add to that usually no PS.  But then, if the market supports the pricing why not.
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KA0HCP
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« Reply #4 on: September 30, 2014, 07:34:57 PM »

One of my TBS-50D's came with the VFO base, and has mounting holes in the base.  The other does not.

I believe the VFO wasn't introduced until about 1952.
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N3GTE
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« Reply #5 on: September 30, 2014, 08:18:42 PM »

I've got one of these...
https://www.flickr.com/photos/53710524@N06/8749417316/
No mic jack...
Terry
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ka4koe
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It's alive. IT'S ALIVE!!!


« Reply #6 on: October 01, 2014, 07:42:27 AM »

I have a Deluxe model. I'll get to it in the winter. Still recovering from the R388 bouncing off my chest.
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w4bfs
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more inpoot often yields more outpoot


« Reply #7 on: October 01, 2014, 09:46:53 AM »

...... Still recovering from the R388 bouncing off my chest.

Hi Feelep .... you weren't wheezing audibly on SAMRC swap net last night ....73
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to see ourselves as others see us.
It would from many blunders free us.         Robert Burns
N3GTE
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« Reply #8 on: October 01, 2014, 04:02:01 PM »

Hey Feelip keep us posted on your progress regarding the H-W. I think you'll find it MUCH easier to deal with than that Valiant. The H-W stays fixed I never found that to be the case with my Valiant. Darn thing was always crapping out.
I've worked on a bunch of them (H-W) and there is a few common issues that crop up mostly do to age. All fixed up it will produce excellent audio with an output of 25-30wts.

Here's a pic of the gang   https://www.flickr.com/photos/42774321@N08/3938290741/

Terry N3GTE
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ka4koe
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« Reply #9 on: October 01, 2014, 11:47:29 PM »

Need to figure out what to do about a PS first. Its sitting by the fireplace right now as avant-garde decoration.
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KC4VWU
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« Reply #10 on: October 02, 2014, 12:09:12 PM »

Uno El,
          Or could that be El Uno? Anyhoo, just roll your own P/S or re-purpose a HP-23 or such. I used a UT-1 until finally giving in and building a dedicated unit. About a year later, I found an original supply in pretty rough shape, but has promise. Just be careful around the output tank, since it's hot with B+; the blocking cap is directly at the output. The one here that is in working condition has problems with arcing across the antenna load cap on a regular basis. Most of the TBS 50's I've seen in person are corroded and rusted due to neglect or poor storage over the years.
         From what I have seen, everyone seems correct in that the antenna connector was originally a ceramic standoff to feed a transmission line against chassis ground, and either upgradeable or modified to use an SO-239 for coax.
          Have fun! With a little TLC, they are a great performer.

73,Phil         
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N3GTE
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« Reply #11 on: October 02, 2014, 08:51:10 PM »

For the P/S you don't want to exceed about 475vdc. The APS-50 (original power supply) runs about 425vdc in HI and 300vdc in LO at 200ma. Exceeding this rating will cause arcing and may damage the 6L6 modulator tubes. Would recommend a choke input. If you are going to use a tube VFO (the original H-W or VF-1 or others) use a separate power supply. All the H-W vfo's I tried to use drifted badly. VF-1 works well.

Phil is correct the tank coils are hot. You can move the plate choke and coupling cap to remove the HV from the coils. If you want to keep the chassis original you can replace the ant connector with a BNC type without enlarging the hole where the ceramic insulator mounts.

I think the HP-23 puts out about 800vdc, way too much for the little TBS-50D
GL
Terry
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ka4koe
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It's alive. IT'S ALIVE!!!


« Reply #12 on: October 03, 2014, 10:51:17 AM »

Anyone tried to convert the voltage doubler in the HP23 to a straight full wave bridge?
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WQ9E
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« Reply #13 on: October 03, 2014, 02:58:56 PM »

It would be easy to convert, should provide around 325-350 volts under normal load depending upon capacitance. 
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RolandSWL
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« Reply #14 on: October 03, 2014, 05:02:14 PM »

Thanks for the info.....

Link to power supply schematic:

http://www.swedeart.com/harvey/manuals/tbs50/tbs50-p24.jpg

RSWL............                                                                                                       


* tbs50-p24.jpg (56.17 KB, 695x900 - viewed 491 times.)
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N3GTE
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« Reply #15 on: October 05, 2014, 10:56:54 AM »

My TBS-50's will run about 10w out @300vdc, the low tap on the power supply. On HI @425vdc will get 22w out on 75mtrs.
Terry
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ka4koe
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It's alive. IT'S ALIVE!!!


« Reply #16 on: October 05, 2014, 05:20:15 PM »

Mine is decoration till I get to it.

PAN


* IMG_6541.JPG (4164.24 KB, 3185x2167 - viewed 349 times.)
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KB2WIG
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« Reply #17 on: October 06, 2014, 10:50:03 AM »

So..... the bunney goes with the Harvey??


klc
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KA0HCP
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« Reply #18 on: October 06, 2014, 01:27:50 PM »

So..... the bunney goes with the Harvey??


klc
Of course.  Haven't you heard of Frequency Hopping?
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ka4koe
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« Reply #19 on: October 06, 2014, 03:09:24 PM »

I guess so. I'm doing the Pookah Polka these daze.
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N3GTE
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« Reply #20 on: October 06, 2014, 07:42:09 PM »

So you think you'll give a modified HP-23 a try?? The H-W can run with 6 or 12v heaters. I think the HP-23 is 12vac for the heathers. They are a blast to use up on 10mtrs when the band is in good shape. Used one with a Drake R-4 and it worked swell!
Terry
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