#81:Heathkit HW-9 QRP CW Transceiver Circuit Walk-Through - Ham Amateur Radio Schematic

This video was by request - a walk-through of the block diagram and schematic of the Heathkit HW-9 QRP CW Transceiver, circa 1984 or so. The block diagram is presented, then a walk through of the simplified block diagram, and finally a walk-through of the transistor level schematic.

[@aramb]

This is a great walk-through. Just dusted off my HW-9 and hope to get it on the air. Many thanks, de N1XU!

[@hankus253]

Great to see this piece on the HW-9. I was a real Heathkit junkie in the 60's and 70's and this and the HW-8 are about the only pieces of ham gear I didn't purchase or assemble.

[@Roy_Tellason]

It's rather curious how the doubly-balanced mixer has a port that's an input in one mode of operation, and an output in the other mode...

[@w2aew]

In many double-balanced mixer designs, the RF and IF ports can be interchanged.

[@crumplezone1]

You are awesome man,who needs school when we have guys like you !!

[@crumplezone1]

teaching as a career will survive the likes of youtube,I liken it to an educational tool like " the open university " in the UK. I have just subscribed to your excellent channel. Salutations from the UK :)

[@w2aew]

I'll have to look around for a schematic... I'll think about picking one up - it would make a better video if I had the hardware.

[@taldeus4008]

Where did you get the schematic?

[@w2aew]

Since this video is 7 years old, I don't remember exactly - but I'm sure it was just a google search for the manual.

[@khawk7365]

Thanks great video. Can you do the mountain topper? I think it is a bit unique with band switching.

[@tunicana]

I'm student in avionics and i think you so much for these this kind of videos it's very much appreciated Alan.i have question about how diodes attenuators works, because its very misunderstood subject in my class.thank you

[@naingaunglwin833]

Where can I get the schematic?

[@w2aew]

it appears to be in this manual: archive.org/details/HeathkitHW9DeluxeQRPTranscievermanual/mode/2up

[@AxelWerner]

seen it already. Awesome as always!! THANKS A LOT! - in your qrp walkthrough video i though the small HF signal would pass "reverse" through the diodes. may that not also be possible if the diode is turned on? (so the signal source is at the diodes cathode traveling to the anode)

[@xierxu]

parts list?

[@w2aew]

Here's the manual: archive.org/download/HeathkitHW9DeluxeQRPTranscievermanual/Heathkit%20HW-9%20Deluxe%20QRP%20Transciever%20(manual).pdf

[@w1jsb]

Brilliant! Thank you. I have been building QRP kits, mostly the Small Wonder Labs SW+ series, as seen on my channel. I also have a 15m Ft. Tuthill that I'm getting ready to optimize for portable operation in a similar way. It would be so nice to add an S meter (I have an analog edge mount type). Are you familiar with either the SW or Ft. Tuthill and know where to tap in for a signal? Could I use the same circuit shown at 11:45 to achieve this?

[@kd5smf]

Hey Alan, I love the walk through & I posted it up on the facebook QRZ group page. Now do one for the HW-8 & HW-7 rigs as I own one of each.

[@cpackard127]

At 10:26 how does IF go through a diode "backwards"? I though they were one way devices in the direction of the arrow. Unless it is at breakdown voltages....

[@w1jsb]

or are there any other recommendations? Any help is much appreciated! Thank you, 73 W1JSB

[@AxelWerner]

so what u are trying to say us is... that the HF AC signal "may pass through a reverse biased diode" while the diode is "switched on" by some much higher DC forward-voltage overlaying the AC signal?hmm. this topic itelf is worth its own little tutorial video :)

[@slaznum1]

It would be nice if you could post your drawings

[@w2aew]

+slaznum1 I post pdf files of my drawings for most of my videos. I started doing this about 2 years ago, but this video was done before I started doing this.

[@hamoudilak6279]

شكرا