Doug Hall dhall at JPS.COM
Thu Nov 13 09:32:32 EST 1997

Mark Langenfeld <mlangen at EXECPC.COM> wrote:
>I have the tech specs for the Hammarlund HQ-145 and HQ-160. What I'd
>appreciate is some practical comparisons between these receivers and, say,
>the HQ-180. Can anyone with hands-on experience comment?

   I've owned an HQ-170, which I understand is basically a ham band-only
version of the HQ-180, so the comparison to my HQ-145X should be useful to
you. I only got rid of the HQ-170 because I wanted a general coverage
receiver and already had two other ham band-only receivers.
   In terms of sensitivity, the HQ-145 is just as sensitive as the HQ-170.
In fact, the HQ-145 has more gain than it needs, and when using big antennas
I sometimes have to back off on the RF gain, even with the AGC on. Both
radios are plenty sensitive. The HQ-170 tended to handle really large
signals better.
   When it comes to selectivity, the HQ-170 wins. While I didn't measure it,
the ultimate rejection seemed better on the 170. The filter on the 145 can
be cranked down pretty narrow, but the ultimate rejection is not as good as
the 170. By the way, many 170's and 180's exhibit poor sensitivity at the
narrow bandwidths, and this is almost always the result of incorrect
alignment. Understanding how to align the IF and doing it correctly will
nearly always restore full sensitivity.
   Both radios (the HQ-170 and HQ-145) exhibit about the same amount of
drift, although the 170 seemed to stabilize a bit more quickly. If I'm going
to use the HQ-145X on CW (and it works fine in that application) I like to
let it warm up for about 40 minutes first. Otherwise it requires a bit of
dial tweaking as the QSO progresses.
   From a fidelity standpoint, my HQ-145X sounds better to me on shortwave
broadcasts and amateur AM transmissions than the HQ-170 did, most likely due
to the wider bandwidth. But if there is a lot of adjacent interference
present you have to crank the bandwidth down anyway, and then the superior
filtering on the 170 comes into play.
   The HQ-170 and HQ-180 have one weakness, in my opinion. Many of them (and
maybe all of them) will "pull" in frequency on strong signals when the AGC
is on. Some are worse than others. It's not an issue on AM, but on SSB and
CW it's a real pain sometimes. I've heard a dozen reasons for this, but I
think the problem is caused by the application of AGC voltage to a pentagrid
converter that's also being used as an oscillator. It's annoying enough that
I never used AGC on CW or SSB with the 170, and I've corresponded with a
number of HQ-170 and HQ-180 owners about the problem. It's not a problem on
the HQ-145X, but that's because there's no product detector, so the issue is
moot. AGC only works on AM with that receiver.
   My 2 cents worth. They all have their strengths and weaknesses, but I've
always thought that all the Hammarlund HQ series receivers were just plain
cool. If you can find an HQ-180 at a decent price (good luck, they're in
demand) go for it. But the HQ-145 is no slouch, and has provided me with
many hours of enjoyable listening and operating.
Doug, KF4KL

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