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HT20 Alive!

Curt
 

The radio worked when turned on, and no smoke escaped!  Alignment was easy as described in the manual.  The receiver is fantastic, and am getting 5W output with a 12VDC supply.  One question is whether I can use the shack 13.8VDC supply without blowing up the finals?  Also, what is minimum voltage?  Will a 9VDC battery work, maybe 1W output?

No contacts yet but that will happen soon.

I think the little green box will become one of my favorites.  When the weather cools a bit, from the patio with an EFHW n tuner ought to be fun.

Thanks Dave and 4state!

Curt KB5JO

Charles W. Powell
 

Typically the value of the electrolytic caps and the heat capacity of the 5v regulators is the limiting factor.  I use 14.1 volts often without any problems.

72,

Chas - NK8O

On Aug 27, 2019, at 2:38 AM, Curt via Groups.Io <rhulett1@...> wrote:

The radio worked when turned on, and no smoke escaped!  Alignment was easy as described in the manual.  The receiver is fantastic, and am getting 5W output with a 12VDC supply.  One question is whether I can use the shack 13.8VDC supply without blowing up the finals?  Also, what is minimum voltage?  Will a 9VDC battery work, maybe 1W output?

No contacts yet but that will happen soon.

I think the little green box will become one of my favorites.  When the weather cools a bit, from the patio with an EFHW n tuner ought to be fun.

Thanks Dave and 4state!

Curt KB5JO

Dave Benson
 

Curt-

A 9V supply will work, although a consumer-grade 9V battery may not last long- its internal resistance will increase pretty quickly as the cells discharge.  A limiting factor on the minimum supply voltage may be the dropout voltage on the 5V regulator- a supply voltage in the 6-7 volt range.  Even then, it may be a graceful degradation.

I've never tried testing it. Let us know how you make out.

BTW- I've used a three-cell (3S) Li-Ion battery quite a bit for portable applications- they're rated at 11.1V nominal and work very well with the Hilltopper.  Mine's a 1.3 Amp-hour battery weighing only 3 ounces.

73- Dave, K1SWL



On Mon, Aug 26, 2019 at 11:26 PM Charles W. Powell via Groups.Io <doctorcwp=yahoo.com@groups.io> wrote:
Typically the value of the electrolytic caps and the heat capacity of the 5v regulators is the limiting factor.  I use 14.1 volts often without any problems.

72,

Chas - NK8O

On Aug 27, 2019, at 2:38 AM, Curt via Groups.Io <rhulett1@...> wrote:

The radio worked when turned on, and no smoke escaped!  Alignment was easy as described in the manual.  The receiver is fantastic, and am getting 5W output with a 12VDC supply.  One question is whether I can use the shack 13.8VDC supply without blowing up the finals?  Also, what is minimum voltage?  Will a 9VDC battery work, maybe 1W output?

No contacts yet but that will happen soon.

I think the little green box will become one of my favorites.  When the weather cools a bit, from the patio with an EFHW n tuner ought to be fun.

Thanks Dave and 4state!

Curt KB5JO

Curt
 

I imagine the 3s Lipo would be great for field portable and own some of those for RC model airplanes, but the furthest get from home with ham radio is the back patio.  Will try out the 9V battery and post my results.  Used that for an ATS-3B years ago, with nearly same transmitter chain from wilds of northern Canada, put out 1W for lot of QSOs.

This little radio is a real jewel IMHO.  Great design, great assembly manual, great packaging, wonderful performance.

Curt KB5JO

Dave Benson
 

Curt-

Thanks for your kind words. :-)

The one thing I've seen with the small 3S batteries intended for RC use-  they don't tolerate a complete discharge.
Twice now, I've accidentally left them powering a rig overnight (in receive) and they were dead.  There's just not room
in the batteries for cell balance and over-discharging protection circuits.  The chargers balk at trying to recharge them,
and I've thrown away two of those batteries so far. 

The LiFePO4 batteries, by contrast, have worked flawlessly for me. 

73- Dave


On Tue, Aug 27, 2019 at 9:03 AM Curt via Groups.Io <rhulett1=consolidated.net@groups.io> wrote:
I imagine the 3s Lipo would be great for field portable and own some of those for RC model airplanes, but the furthest get from home with ham radio is the back patio.  Will try out the 9V battery and post my results.  Used that for an ATS-3B years ago, with nearly same transmitter chain from wilds of northern Canada, put out 1W for lot of QSOs.

This little radio is a real jewel IMHO.  Great design, great assembly manual, great packaging, wonderful performance.

Curt KB5JO

Curt
 

My results are: Fresh 9V battery ( 9.3VDC) - 600 mW; 8xAA fresh (11.3 VDC) - 4W; 7AH gelcel (12.2 VDC) - 6W; Shack 20 amp supply ( 13.8 VDC) - 8W.

So guess the 8xAA will fit need without stressing the finals.  The 8xAA provides 2000 mAH.

72, Curt KB5JO

Curt
 

I hear the LiFePO4 batteries are more robust LiPo although have never used them.  For sure the lipos don't like total discharge or overcharge and can puff if subjected to either.  I use a balancing charger for the LiPo and they maybe are too delicate for banging around in a back or "go" pack.  I understand they can catch fire when abused although have never had that happen with the model airplanes.  I treat the LiPo like fine china and keep them in a special charging pack when not flying in an airplane.

Now to make some QSOs with emerald QRP.

73, Curt KB5JO

Curt
 

Just made contacts with MO n CA @ 4W to an 80M dipole up 50'  CA is 1400 miles, gave me a 539.  Of course he has a log periodic up high

Curt KB5JO