HRO Receivers

[WA4WAX]

I am going to post this as a stand alone, having mentioned it in a post on the NC-300.

When aligning an HRO series set, do NOT align to 455 KHz!  Instead, find the peak of the set's crystal filter, and peak the IF chain on this frequency.  In my set, this frequency is 456.2 KHz. Others will vary.

The frequency response of these crystal filters can shift due to age, humidity, etc.

Good luck!

[w3jn]

True of any receiver having a single crystal filter; however, the 6+ KC bandpass of the IF stages after the crystal filter makes this probably a little bit moot.

It IS critical that the crystal filter stage be aligned at exactly the crystal frequency, however.

[N3GTE]

You wouldn't want to arbitrarily align the IF at 455kc as most of the pre war models use 456kc. I have a '36 model and it seems to have a pretty tight IF bandpass. Just guessing I would say 5-6kc tops. It's a little hard on the ears the listen to AM on. Here an old post about it from '12:
http://amfone.net/Amforum/index.php?topic=30965.0;wap2

Need to do some more work to hear if I can make it a little more AM friendly but have been working on a digital dial for it. Those little charts are getting smaller and smaller as I get older.

Terry