tuning up on 160 meters

[N5YPJ]

I just acquired a Cantenna and decided to try tuning my ts-830 on 160 meters where I've yet to put up an antenna on my city lot. Tuning as I do on the other bands and per the manual on 160 has yielded some strange results - actually I don't get past dipping the plate. Dipping the plate is very broad and I wind up with the control pointing to near 14 Mhz before seeing any dip and the dip is not very significant. The load is set at or near minimum. Every other and tunes up well. Am I doing something wrong or should I look to the radio?

[G4LNA]

I don't know what a Cantenna is, but have you tried tuning the radio up into a dummy load first to make sure it is actually working?

[N5YPJ]

A Cantenna is a dummy load made by Heathkit back in the day. The radio otherwise is working fine.

[K9STH]

LNA:

The Heath CN-31 "Cantenna" is a 50 ohm, 1 kW, dummy load that was made from 1961 until 1991. It was, by far, the longest, in terms of time frame, product that Heath made.

Glen, K9STH

[G4LNA]

I was into amateur radio in the '60s, I wonder why I never heard of it? Oh well, just made myself look an idiot

[W0BTU]

Dipping the plate is very broad ... The load is set at or near minimum.

A broad dip on 160 is typical. I can't say where the dip should be on that rig. Perhaps the fixed padding cap that is switched across the tuning capacitor on 160 is not the correct value. What happens if you move the loading control?

The main thing is, does the rig put out maximum power with both the controls between min and max?

[WA7PRC]

A broad dip on 160 is typical. I can't say where the dip should be on that rig. Perhaps the fixed padding cap that is switched across the tuning capacitor on 160 is not the correct value. What happens if you move the loading control?

The main thing is, does the rig put out maximum power with both the controls between min and max?

That's what I'd bet on, or a problem with the switching/wiring.

Oh well, just made myself look an idiot

You needn't do that. Others will do it for you.

The Heath CN-31 "Cantenna" is a 50 ohm, 1 kW, dummy load, etc...

The Heathkit "Cantenna" was model HN-31 (and later, HN-31A). It can handle a kilowatt for 10 seconds if you use transformer oil. It can handle less time/power if you're using mineral oil. Otherwise, it's just a 90W Globar™ resistor sitting in 1 gallon of oil without anything other than the can to pull the heat away from the resistor:



The HN-31A didn't have the RF detector. I recently rebuilt my HN-31 (the resistor had been overheated and the unknown oil was VERY old. Free replacement oil was as close as the local electric utility's transformer shop. It now works as well (or as poorly) as original. I use it as a load for barefoot rigs but use my homebrew air-cooled 1.6KW dummy load for testing high power sources (all day if needed).

[WB2WIK]

The Heathkit "Cantenna" was model HN-31 (and later, HN-31A). It can handle a kilowatt for 10 seconds if you use transformer oil.

It's actually 1 kW for 10 minutes with the right kind of oil. Mine has Shell Diala transformer oil in it and I've hit it with a kW for several minutes at a time with no issues, not even popping the pressure relief valve.

I wonder if this is the highest volume product Heath ever sold? At one time, everyone I knew had one. Or two.

Well, maybe not my great aunt Tilly.

[WA7PRC]

It's actually 1 kW for 10 minutes with the right kind of oil. Mine has Shell Diala transformer oil in it and I've hit it with a kW for several minutes at a time with no issues, not even popping the pressure relief valve.

I wonder if this is the highest volume product Heath ever sold? At one time, everyone I knew had one. Or two.

Well, maybe not my great aunt Tilly.

Oops! Yep, it is 10 "minuets". Still, after I refurbed mine, I noticed it got kinda warm after about 30 seconds with about 1KW CW pumped into it. My HB dummy barely gets warm after several minutes (while the 3-500ZG anodes are quite cherry).

[KM1H]

Originally Posted by W0BTU
A broad dip on 160 is typical. I can't say where the dip should be on that rig. Perhaps the fixed padding cap that is switched across the tuning capacitor on 160 is not the correct value. What happens if you move the loading control?

The main thing is, does the rig put out maximum power with both the controls between min and max?

That's what I'd bet on, or a problem with the switching/wiring.

There is no switch or wiring problem involved, thats the way it was shipped because the JA 160M band was above 1900 and it made spec....barely. There has been a bit written about adding some padding and peaking the tuning just for a small range of interest if its really that important. Mine does at least 85W at 1800 and 110 at 2000 with new tubes and an alignment touch-up.

Carl