QRP Club

QRP Station => Transceivers => Topic started by: PA1FJ on January 13, 2015, 20:36:29 UTC

Title: HW-7 mods
Post by: PA1FJ on January 13, 2015, 20:36:29 UTC
Does anyone have experience with the modifications of the Heathkit HW-7.
Specially the Better ears for HW-7.

72 Fred PA1FJ
Title: Re: HW-7 mods
Post by: KC8AON on January 14, 2015, 12:30:31 UTC
I had an HW-7 once and it was the worst receiver I have ever heard.  Looked at some of the mods but looked like more trouble than it was worth so I sold it.  Have had 2 HW-8's and they are a great little rig but still not up to todays standards.  My little elcheapo MFJ 40 meter Cub will work circles around either of the Heathkit rigs !  Do yourself a favor and save the HW-7 as a collector only, and get something better to put on the air that you can enjoy !
Title: Re: HW-7 mods
Post by: PA1FJ on January 14, 2015, 15:50:46 UTC
The HW-7 is for me more a hobby project than a Transceiver where I join make QSO's, since I have better sets for such as the FT-817.

72 Fred PA1FJ
Title: Re: HW-7 mods
Post by: KC8AON on January 14, 2015, 20:53:13 UTC
It would definitely make a good hobby project !  Lots of room for improvement, but from what I've read, its basically a major rebuild to make it useable.  I'm sure if you do some google searching, you would find lots of info !  Good luck my friend.

73,
KC8AON
Title: Re: HW-7 mods
Post by: PA1FJ on January 20, 2015, 15:29:26 UTC
HW-7 modified SBL-1 Mixer, 40673 as LO buffer.
Works great better than original, and that for 25 Euro!!
Really QRP!

72 Fred PA1FJ
Title: Re: HW-7 mods
Post by: KC8AON on January 22, 2015, 13:34:00 UTC
Anything would be better than original on an HW-7 - the one I had was horrible on receive!
Title: Re: HW-7 mods
Post by: N8XEE on February 26, 2015, 03:46:28 UTC
Anything would be better than original on an HW-7 - the one I had was horrible on receive !

It's actually no worse than any other DC receiver...  The sensitivity is just fine.  It's the selectivity that's a problem, as it's very wide.  The easiest (and least invasive) mod is to add an outboard audio filter between the rig and your headphones.  Mine has 6 steps that go from 2,500 Hz down to about 100 Hz.  I usually run it around 400Hz, which is plenty narrow for all but the most crowded band conditions.  The Four State QRP Group sells a kit for about $20.  It has a 50dB notch at 200Hz.  There are other kits that range from about the same up to just under $100.  Well worth the money.
Title: Re: HW-7 mods
Post by: WB3T on May 07, 2015, 00:09:20 UTC
I think the HW-7 has gotten a bad rap. Mine works fine with a few simple mods and an outboard audio filter. Rebuilding the whole receiver section is NOT necessary! Here's mine with a DSP unit, but the Four State SCAF filter does just as well.

https://www.youtube.com/watch?v=EpPGC2XQT4A (https://www.youtube.com/watch?v=EpPGC2XQT4A)

A description of the mods can be found here: http://radiowb3t.homestead.com/heathkit.html (http://radiowb3t.homestead.com/heathkit.html)

Good luck!
Bob, WB3T
Title: Re: HW-7 mods
Post by: F5MPN on November 18, 2021, 09:09:15 UTC
Hello

I ask you a simple question regarding the bias of the diode. Is it in passing or reverse (biased) mode. If you could give me a little more information.
Best Regards

F5MPN Stéphane
Title: Re: HW-7 mods
Post by: ac9xh on February 13, 2022, 02:07:23 UTC
I love the hw-7 and hw-8
so if anyone here has one to get rid of let me know. I have several articles on mods for both these rigs

73
David
ac9xh
Title: Re: HW-7 mods
Post by: KX4UL on February 15, 2022, 01:03:07 UTC
I have an HW-8 for sale.  It's in excellent condition...9.5/10.  Worked as it should last year but has not been used since.  I seem to have misplaced the DC cord.  Why is your call sign not showing up on QRZ lookup???
Title: Re: HW-7 mods
Post by: WA4IOR on February 15, 2022, 01:48:19 UTC
my HW- 7 works fine and my HW-8 all so, have 2 HW-8`s one needs a front panel cabinet like to buy one.