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 Post subject: HAMMARLUND HQ-180C slot frequency and vernier tuning
PostPosted: Feb Fri 16, 2018 10:47 pm 
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Joined: Dec Wed 02, 2009 3:55 pm
Posts: 35
When tuning the slot frequency knob to the zero position the S meter does not go down.
I did turn the slot depth pot to the center position as the manual requires.
Only when in the minus 2 KCS position does the S meter respond to a lower reading.
According to the manual at zero there should be a drop off on the S meter.

Also the vernier tuning knob should vary the frequency a little bit but it has no effect.
What am I doing wrong?

Tnx,
Al


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 Post subject: Re: HAMMARLUND HQ-180C slot frequency and vernier tuning
PostPosted: Feb Sat 17, 2018 12:21 am 
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Joined: Sep Wed 10, 2014 2:01 am
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Location: Costa Mesa, California
If you go to page 49 of the manual, it tells you what the controls are set at before adjusting L3 for minimum reading of the VTVM connected for alignment. This should correspond to a minimum S meter reading during operation. Has the radio been aligned recently? It sounds like it just needs to be aligned.

Norm

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 Post subject: Re: HAMMARLUND HQ-180C slot frequency and vernier tuning
PostPosted: Feb Sat 17, 2018 12:41 am 
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Joined: Jun Sun 19, 2011 2:31 pm
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Al,

I agree with Norm. Has the receiver been aligned? If not the BFO and slot frequency adjustments are probably off a bit along with the rest of the IF strip and that will be cured during alignment. The slot depth control will also be adjusted for maximum depth during alignment and it probably won't be exactly at the 1/2 setting. The slot filter frequency is adjustable via its coil but make sure that the rest of the IF strip and BFO are set correctly before resetting this adjustment. With everything properly aligned and the receiver tuned so that its calibrator is tuned to zero beat with the BFO set to zero adjusting the slot control to zero should result in maximum attenuation of the signal. Note that there is slight interaction between the notch frequency and depth control so you have to iterate between both of them when doing this part of the alignment.

Check to see if the variable capacitor driven by the vernier control is moving when you turn the knob. It uses a reduction drive with very low torque capability so if the capacitor is dragging it won't turn. The action of the vernier control is most obvious with the BFO active tuning in a CW or SSB signal. The vernier control is through a capacitor in parallel with the oscillator coil and a pair of fixed capacitors used for the final conversion stage from 455 Khz. down to 60 khz. so it is a simple circuit. If the capacitor is turning then check for a broken wire from the variable capacitor to the rest of the circuit.

Rodger WQ9E


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 Post subject: Re: HAMMARLUND HQ-180C slot frequency and vernier tuning
PostPosted: Feb Sat 17, 2018 12:59 am 
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Joined: Sep Wed 10, 2014 2:01 am
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Location: Costa Mesa, California
I see Rodger covered this while I was typing so some of this is duplication of his suggestions. C156, for dial frequency correction is connected across L4 in the 395 KHz oscillator. This slightly changes the oscillator frequency that mixes with the 455 KHz second IF to produce the 60 KHz third IF. If L4 has been mis-tuned, it may mean that C156 can't affect the oscillator frequency enough to show on the dial. The alignment procedure for these radios should be followed in the sequence shown in the manual with all controls set ahead of time as described in the beginning of the alignment section. If after full alignment there are controls that do not function correctly, then is the time to investigate possible problems.

Norm

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 Post subject: Re: HAMMARLUND HQ-180C slot frequency and vernier tuning
PostPosted: Feb Sat 17, 2018 4:05 pm 
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Joined: Dec Wed 02, 2009 3:55 pm
Posts: 35
Thanks to everyone for your input with lots of good information.
I am leary about using my golden screwdriver on this complex radio.
I got it on Ebay recently and looks great but don't know if it was realigned.
It's very sensitive with only 2 feet of wire and pulls in lots of stations.
The frequency read outs are also spot on.

The vernier tuning is mechanically sound, no slippage.
So will have to think about this some more.
Thanks once again to all for helping me.

Al
K2DYH


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 Post subject: Re: HAMMARLUND HQ-180C slot frequency and vernier tuning
PostPosted: Feb Wed 21, 2018 5:15 pm 
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Joined: Apr Sat 09, 2016 1:26 pm
Posts: 35
I strongly recommend you check out K7PP's YouTube page. He has several videos on the HQ-180, alignment and restoration.
https://www.youtube.com/channel/UCwRV-S ... rZiVAXM9jA


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 Post subject: Re: HAMMARLUND HQ-180C slot frequency and vernier tuning
PostPosted: Feb Wed 21, 2018 5:47 pm 
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Joined: Dec Wed 02, 2009 3:55 pm
Posts: 35
Hi, thanks for the info. Guess what.
I found that the cable that comes from the vernier tuning control is not connected to anything.
The bad part is the proper location is covered completely by the SSB switches.

Al
K2DYH


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 Post subject: Re: HAMMARLUND HQ-180C slot frequency and vernier tuning
PostPosted: Feb Thu 22, 2018 3:35 pm 
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Joined: May Tue 16, 2017 3:03 pm
Posts: 142
Location: Potomac, MD 20854
Dumb question; when you turn the slot control COMPLETELY counterclockwise is the red knob pointing at 9 o'clock and fully clockwise to 3 o'clock? Since the slot is WORKING, seems like the pointer might just be misaligned. It sounds like something simple like that. An alignment of this beast is not for the faint of heart; if it is working I would just leave alone. But slot adjustment ONLY is not too bad, but signal must be MAX with variable cap either fully open or fully closed and THEN you shove your tuning instrument into the coil for a minimum once you set it strait up to 12 o'clock position.

I had a busted slot control on mine; had broken wires on my coil and finally got a replacement and now works great.

paul


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 Post subject: Re: HAMMARLUND HQ-180C slot frequency and vernier tuning
PostPosted: Feb Fri 23, 2018 5:48 pm 
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Joined: Dec Wed 02, 2009 3:55 pm
Posts: 35
Thanks for the info Paul.
Everything lines up correctly as mentioned.
However I did some jiggling with the slot depth coil and control and got it to lower the S meter reading right on the zero frequency mark but it doesn't block the signal a lot.
I would not attempt an alignment with three dozen cans and padders.

AL


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 Post subject: Re: HAMMARLUND HQ-180C slot frequency and vernier tuning
PostPosted: Feb Fri 23, 2018 9:11 pm 
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Joined: May Tue 16, 2017 3:03 pm
Posts: 142
Location: Potomac, MD 20854
with the pointer straight up at 12 o'clock you should be able to adjust the POT for minimum S meter and also tune the coil for minimum S meter. turn BFO on and use CAL as the source of the signal; use RF gain to make your signal S9 or so at max (with slot at 9 o'clock position), then move slot to 12 o'clock and tune the POT and turn slug to go down. I think I get more than 4 or 5 S units reduction with my slot control (IIRC).

paul


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 Post subject: Re: HAMMARLUND HQ-180C slot frequency and vernier tuning
PostPosted: Feb Sun 25, 2018 6:24 pm 
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Joined: Dec Wed 02, 2009 3:55 pm
Posts: 35
I went thru all the suggested steps and it did make a difference.
The S meter went down right at the 12 o'clock position.

Thanks again,
Al


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