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Author Topic: Add 30 meters to HW 101  (Read 3179 times)
WA9CFK
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Posts: 98




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« on: February 14, 2013, 11:56:53 AM »

This may have been asked before but has anyone tried to add 30 meters or other Warc bands to an HW101?

If nothing else the top two 10 meter slots should be available for rewiring.
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W4OP
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« Reply #1 on: February 14, 2013, 11:58:46 AM »

Instead of modifying a nice BA, why not build transverters?

Dale W4OP
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N2EY
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« Reply #2 on: February 14, 2013, 02:27:59 PM »

I don't know anyone who has tried, let alone succeeded. Here are some things to consider:

1) What band are you willing to give up to get 30? You can't just use one of the 10 meter segments.

2) The first IF of the '101 tunes 8895-8395 kHz (yes, it tunes backwards). If you put in a heterodyne crystal for 10.0 to 10.5 MHz, the first IF will be 8795-8745 when you tune 10.1 to 10.15. The various tuned circuits may not be able to reject the IF adequately.

3) The VFO tunes 5.5 to 5.0 MHz. If you put in a heterodyne crystal for 10.0 to 10.5 MHz, the VFO will tune 5.4 to 5.35 when you tune 10.1 to 10.15. The various tuned circuits may not be able to reject the second harmonic of the VFO adequately.

4) The HW-101 is mostly on PC boards - including most of the bandswitch sections. Changing parts isn't simple.

----

One of the biggest challenges to designing multiband HF amateur transceivers and matched-pair separates in the 1960-1980 era was coming up with a heterodyne scheme that used available components and would not put spurs, harmonics and other junk on the air. Heath's system worked well for 80/40/20/15/10 - so well that Kenwood copied it for several of their rigs (best known is the TS-520 family) and Yaesu modified it slightly for the FT-101 family (they moved the second IF down a little bit).

The WARC bands were a major reason for the move to "up converting" rigs, because it became almost impossible to come up with a heterodyne scheme that would work well on all 9 HF/MF bands.

----

It might be possible to take a basket-case '101 and redesign it to cover the WARC bands by using different VFO and first-IF frequency ranges. Such a redesign would require some serious engineering, but could potentially result in a pretty decent result.

73 de Jim, N2EY
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WB2WIK
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« Reply #3 on: February 14, 2013, 02:43:56 PM »

Anything's possible, but this is a pretty big re-build.

Not just changing the heterodyne oscillator crystals (pretty easy) but also their tuned circuits in the het osc cathode follower; as well as the 2nd TX mixer tuned circuits; the driver/preselector tuned circuits; and the final power amplifier tuned circuits.

A lot of stuff to change.  Worth it?
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KA4POL
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« Reply #4 on: February 14, 2013, 10:03:52 PM »

There was a discussion of that topic last year around June/July in the Heathkit Yahoo group.
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G3RZP
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« Reply #5 on: February 15, 2013, 12:52:39 AM »

There will be a big birdy on receiver when the tune frequency is twice the VFO, and it's possible that on transmit, the IF will be too close and it won't meet FCC unwanted emission requirements.  I don't know if, as built, it does on 40m, either.

'Don't ask, don't tell'.
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AC5UP
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« Reply #6 on: February 15, 2013, 04:26:43 PM »

............shame on you for suggesting the venerable HazWaste-101 from Heathshkit is anything less than perfection wrapped in Benton Harbor green!


Grin
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WA9CFK
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« Reply #7 on: February 18, 2013, 02:41:22 PM »

I should have known that if it was easy, the web would be full of modification methods. Smiley

I have an HW 101 that has been on the shelf for a few years. My chances of ever using anything above 28.5 MHz are pretty slim but I like to work 10 MHz and 18 MHz occasionally. Particularly to avoid contests. Wink

It seemed like a good idea at the time, I suppose the smart thing to do is sell it to someone who appreciates it and apply the money towards some other piece of ham gear I cannot live without.       
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G3RZP
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« Reply #8 on: February 19, 2013, 07:55:46 AM »

Shouldn't be that hard to make a transverter.
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