HRO-60 on AM

[K6JEK]

Have any of you stagger tuned an HRO-60 for AM?   Was it devilishly hard?  How did it turn out?

I have a line on an HRO-60.   I've been told that unlike the HRO-50's, the 60's are too narrow for nice AM but this can be overcome by stagger tuning the IF's and once that's done they sound good and have steep skirts, something that might be useful against the QRM we occassionaly encounter.

Jon 

[David, K3TUE]

I've been told that unlike the HRO-50's, the 60's are too narrow for nice AM

While I have never owned or used one, this runs counter to all I have head about the HRO-60.

[Jim, W5JO]

I have one and it turnes AM fine with good fidelity.  If it needs stagger tuned, it may have bad silver micas in the IF transformers, or someone doesn not have them tuned right.

[nq5t]

I've been told that unlike the HRO-50's, the 60's are too narrow for nice AM

I wouldn't call the HRO-60 "too narrow", but they're not 8 Khz wide, either -- the spec, as I recall, is 3.5 Khz max bandwidth, with decent skirts.  That's a bit tight, but they do play well and sound pretty good.  I wish I had not sold mine.  If it's possible to widen the nose selectivity some by stagger tuning, that would be a good thing.

The  HRO-50 has a 15 Khz max bandwidth and is single conversion.  I believe the 50-1 has roughly the same IF strip as the HRO-60.

Grant/NQ5T

[Jim, W5JO]

At 60 db attenuation the bandwidth with the crystal filter off is just over +/-5 Kc. dropping to +/- just over 2 with the filter on position 5.  I like the sound output and the book says with the tone control off, it will go from 90 cycles to about 9 Kc.  This all assumes it is in proper condition

[Don, W2DL]

If I want what I personally consider the best AM receiver I have in terms of audio quality I pick, without a moments hesitation, my HRO-60. I also have available a NC-173, a Drake 2B, a Collins 75A3 (with 8 kc L-C filter), a TS 950DSX and a 756 PRO. Each of the above receivers is connected to it's own 8 - 10" speaker in a shelf enclosure, we are not talking about the miserable built-in speakers in some of the above. And, audio aside, I just like the way the HRO tunes and pulls in the signals!

Don, W2DL

[W3SLK]

Don, I would like to see the schematics for that L-C filter. If you could please send me a PM on the board and we can work out the smaller details. I have a 75A3 with the stock 3.1Kcs mech. filter and it is horrendous.

[W1DAN]

Hi Jon and all:

Having had many HROs my opinions are:

The HRO-60 has a tight IF strip. It is a good radio to use when there is adjacent interference. I have not stagger tuned an IF, but the idea is not hard. The old HRO-50 has the wider IF like the HRO-5 (the HRO 50T1 has the same IF strip as the HRO-60) and thus passes more midrange and highs.

Most HRO-60's except for the latest ones had detector distortion. This can be reduced by loading the detector with about 10k.

The audio power stage does not have a lot of low end due to the wimpy output transformer. I get better sound by using an external amp and pulling the 6V6 tubes. An added benifit is the power transformer is unloaded quite a bit and does not get nearly as hot.

Just my thoughts...

73,
Dan
W1DAN