[HBR] My New HBR-13 Running FB on 40m CW

[ejparagi at aol.com]

Hello Scott,

I too have been following the story of your HBR build and I agree with others who have complemented you on  your construction.  I think part of the reason more people don't take on a large project like this is the amount of time spent on metal working to make a good looking finished product.

In the absence of a spectrum analyzer and tracking generator, one can look at IF passbands with a sweep generator, a bridge, a diode detector and an oscilloscope.  I used such an arrangement for many years while aligning VHF and UHF low pass transmitter filters.  The 'scope display will look just like a textbook plot when all is set up correctly and the circuit is swept at the correct speed.  The bridge and detector were actually combined in a trade-marked device called a "Rho-tector," which was a common item in RF labs 40 years ago.  I think they were made by Telonic Microwave, but I cannot verify that at the moment.  There isn't much to one- you could easily fabricate one yourself.  

It helps to have a way to put a marker or two on the sweep signal.  Most of our sweep generators had built in crystal oscillators to provide a marker function and it would make sense to use that method if you do a lot of work with the same IF frequency.  If you have a counter, you could probably build a couple of non-crystal controlled oscillators and check them occasionally for accuracy when you are making the final adjustments to the bandwidth. 

Please keep us up to date on further progress with the HBR.

73,
Ed
WB9RMA


-----Original Message-----
From: Whitebear1122 <whitebear1122 at comcast.net>
To: HBR Receiver List <hbr at mailman.qth.net>
Sent: Thu, Jul 11, 2019 8:15 pm
Subject: [HBR] My New HBR-13 Running FB on 40m CW

I’ve been listening every night to 40m cw on my HBR-13L and it is such a joy to listen to signals from a radio that I built myself.  I’ve been wanting to build my own receiver since 1966.  I am actually shocked that I pulled this off considering it was the first radio project that I’ve ever built.  

Tonight I was experimenting with the 100 KC IF transformer coupling with those ARC5 military IF transformers.  Initially I was running them with maximum coupling, signals were really loud, and the bandwidth really wide.  Tonight I minimized coupling on all 4 IF’s and it did narrow up the bandwidth quite a bit.  I think there is plenty of gain in the regenerative IF’s to overcome the lighter coupling.  I wish I had a spectrum analyzer with tracking generator and I could see the change in bandwidth depending on coupling.  I have been eyeballing that Rigol DS815 spectrum analyzer…. it would have helped my initial troubleshooting quite a bit.  I am planning on building a CW/SSB transmitter next and a spectrum analyzer would be a big help.  

Tonight I was reading the HBR-13 Notes from the HBR website.  The first time I read them not much registered.  This time everything registered.  I really had to build it to understand 

I still have to learn how to adjust the BFO variable caps and coil better.  I thought I had it tuned tonight but it was clearly way off.  I better go back to the HBR-16 article and re-read that.

I’m still having trouble with the S-meter and will replace it this weekend and see if that makes a difference.

I don’t have the radio in a cabinet yet.  I have two commercial cabinets to pick from.  One is a Hallicrafters cabinet that would accept the rack mount., and the other is a cabinet from an old commercial oscillator.  I plan to bring them in from the garage rafter storage and see if it’s something I want to use.  Otherwise I might try building a cabinet like K4CHE did, a minimal cabinet built directly up to the chassis and doesn’t waste an inch of space.

Just curious if there are many HBR folks on this list anymore.  Anyone building an HBR?

73, Scott WA9WFA




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