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Author Topic: Heathkit GR-78 tunes about evening time hf bands  (Read 380 times)

ALPARD

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Heathkit GR-78 tunes about evening time hf bands
« on: April 26, 2020, 02:11:53 PM »

Got my old gr-78 out, and it is still working quite well.
The battery was a bit low, but pulled the signals ok.

https://youtu.be/PcYfUYisHfA
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ALPARD

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Re: Heathkit GR-78 tunes about evening time hf bands
« Reply #1 on: April 30, 2020, 03:11:06 PM »

More tuning about the 80m band with the Heathkit GR-78 tonight.

https://www.youtube.com/watch?v=cxfBB0TpQUQ
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ALPARD

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Re: Heathkit GR-78 tunes about evening time hf bands
« Reply #2 on: April 30, 2020, 03:24:55 PM »

The GR-78 listening the MW band. :)

https://www.youtube.com/watch?v=jT2ELshKlyQ
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ALPARD

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Re: Heathkit GR-78 tunes about evening time hf bands
« Reply #3 on: May 01, 2020, 04:50:28 PM »

This is the GR-78 on 20m during day time.  The band is still not in good condition on 20m.

https://www.youtube.com/watch?v=rrV1otUnJAE
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ALPARD

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Re: Heathkit GR-78 tunes about evening time hf bands
« Reply #4 on: May 03, 2020, 03:24:12 AM »

I have uploaded some vid clips of the vintage Heathkit GR-78 from 1970s, because I found that it is a very nice sounding, sensitive and quiet receiver. I was surprised by its performance.

Mind you that the HF condition is still pretty poor, and I was not hearing much with other receivers using exactly same antenna.

This GR-78 pulls signals well, and is very pleasant to listen to. It is a keeper.
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ALPARD

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Re: Heathkit GR-78 tunes about evening time hf bands
« Reply #5 on: May 03, 2020, 03:30:23 AM »

The GR-78 receiving  80m amateur band rag chew session between NA and EU hams last night. I have never heard NA hams that loud and clear on 80m band ever. I was totally surprised.

https://www.youtube.com/watch?v=uBgCZwkv_ME
« Last Edit: May 03, 2020, 03:35:34 AM by ALPARD »
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ALPARD

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Re: Heathkit GR-78 tunes about evening time hf bands
« Reply #6 on: May 03, 2020, 03:58:03 AM »

The antenna was just random length of wire in the garden.
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VE3WGO

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Re: Heathkit GR-78 tunes about evening time hf bands
« Reply #7 on: May 06, 2020, 09:17:49 AM »

your GR-78 is a very nice sounding radio.  It looks great too!
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ALPARD

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Re: Heathkit GR-78 tunes about evening time hf bands
« Reply #8 on: May 06, 2020, 12:19:15 PM »

Thank you.  Yes, that GR-78 has been in storage for long time. I have not expected much from the radio, but when I took it out and powered on a few days ago, I was really enjoying listening to it.   It is not going back to the cupboard, but it is now permanently set up as my main HF receiver along with the KENTWOOD R820.

It hears everything that my ICOM and KENTWOOD hear. It is not perfect especially in selectivity, but hey it is about 45 years old, and I got it almost for nothing. 

It is especially good on 80m SSB at night, but also quite nice on 20m band. BCL is also great that it is very quiet, and yet it receives DX stations very well. :) 
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VE3WGO

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Re: Heathkit GR-78 tunes about evening time hf bands
« Reply #9 on: May 17, 2020, 09:06:53 AM »

I remember seeing somewhere online, the optional ham bands bandspread dial scale that could be substituted for the regular one.  Do you have that one installed too?  It looks useful.

73, Ed
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N8YX

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Re: Heathkit GR-78 tunes about evening time hf bands
« Reply #10 on: May 18, 2020, 07:46:36 AM »

...but it is now permanently set up as my main HF receiver along with the KENWOOD R820.
Hopefully

A) You have a ham ticket;

B) You have the R-820 set up with a TS-820S in a twins configuration. Extra points if you also have the SM-220/BS-8 and an SP-820 in the lineup.

I got my first R-820 in 1988 and that rig (along with its companion TS-820S) saw almost constant use for two decades before being removed from the lineup for R&R. Both radios had 12 and 17M added to them (per a 1983 QST article) and I have the components required to add 30M to the TS-820S's WWV spot.

A second pair of twins arrived in 2005 and some time after that, a 3rd R-820 "for parts or not working". The latter was a major effort to get working but get it working I did. All the ham-band segments were changed to corresponding SWBC or Ute ranges not covered by the rig's built-in SW Converter Unit - e.g., 14.0 became 13.5 for the 22M SWBC allocation.

If you carefully study the R-820's schematics you'll note that only the 29.5MHz segment activates the Converter. This can be changed to enable all four 10M segments to activate it by the addition of a few 1N4148 or similar diodes on the 28.0-28.5-29.0 band-select lines to the Converter Enable line. Doing so gets an entire 2MHz per selection. In this way it's possible to add 30 and 17M coverage plus a lot more SWBC coverage along with some interesting Ute ranges. Changing the Converter HFO crystals to align the digital display and analog readout with band edges ("0" or "5" start points) both is easy to do and recommended once you've made the first modification. Similarly, each Converter bandpass filter can be tweaked (by component changes or coil adjustment) to allow optimum reception across each 2MHZ-wide Converter range.

Anyone wishing details of the R-820 mods, adding WARC bands to the rigs or where to get the parts for the R-820 end of the Transceive cable can PM or email me. I've also written these up elsewhere around the 'Net. Mine are cycled in and out of my vintage operating position and at the moment all 3 are out of the lineup for filter additions and other service work. Nevertheless, they're definitely keepers.
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WB4SPT

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Re: Heathkit GR-78 tunes about evening time hf bands
« Reply #11 on: May 20, 2020, 09:04:02 AM »

I'm glad your unit is working well for you.   My GR78 experience was different.  In those days, my previous SWL radio was the lowly GR64.   But, I far preferred that audio than the 78.  The 78 was so bad I even attempted a different audio driver IC. 
Anyway,  I'll bet that old NiCad is long deceased.   Dispose that cadmium properly!    ;D
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ALPARD

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Re: Heathkit GR-78 tunes about evening time hf bands
« Reply #12 on: May 21, 2020, 01:17:03 AM »

Yup, I operate ham radio too, but SWL is enjoyable activity at times, especially when the HF ham band condition is poor.

I like my R820, but it does not cover all bands. It has gaps in the freq. it covers. So having some other receiver with full HF coverage is good.

My GR-78's ni-cad had died long time ago, so it had been pulled out and discarded, and I am running it with external 12V battery.  Any DC voltage 9V - 12V seem works OK.

The audio of the GR-78 gets raspy at times, but I found the GR-78 very fun to listen to.  It has that classic vintage audio, and also it is very quiet and sensitive. I did comparison side by side with other more modern and higher grade rigs, and this GR-78 was as good as them, sometimes even better than them in copying weak signals.

I didn't expect such performance from this humble GR-78 when took out after long storage, but pleasantly surprised, hence made a few videos.

73 de Al.
« Last Edit: May 21, 2020, 01:19:36 AM by ALPARD »
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