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Author Topic: Looking for Portable (Not Mobile) XCVR  (Read 4378 times)
AA4PB
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Posts: 12807




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« Reply #15 on: April 25, 2012, 11:57:02 AM »

The Elecraft K2 (10W version) will be easy on receive current. Its a good choice if you are into kit building and CW. The Elecraft KX3 should also be well within your budget and much smaller in size.
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WB6BYU
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Posts: 13177




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« Reply #16 on: April 25, 2012, 01:34:16 PM »

My Elecraft K2 runs about 175 to 225 mA on receive, depending on what options I have
selected, and about 2 amps at 10 watts output.  You can also get a 100W PA for it,
though I don't know how easy it is to bypass the amp to save current when you are
operating at low power.  The receive current shouldn't change significantly, however.

It seems to run well as the battery voltage drops, but I haven't tested it to see how
low it actually operates.
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KF7DS
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Posts: 189




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« Reply #17 on: April 25, 2012, 02:31:25 PM »

As others have said, if you want 100W and a small gel cell, the two are not compatible... Regardless of the apparent peak current of the gel cell.

I run a Kenwood TS480SAT (100W) "car portable" where I use a leisure battery to power the transceiver and also to power a laptop for logging and DX Cluster purposes. I can operate for around 6 or 7 hours without the battery Voltage sagging too low. The battery is a 110 Ah job which is now 5 years old and is being replaced this spring with another similar one. After 6 to 7 hours use the battery is well down.

Another consideration is the ability of the battery to survive deep discharge. The smaller the capacity, the deeper will be the discharge and the shorter the life.

My K3 is perhaps typical of the efficiency (or lack of it) when running less than full power. The current from it is as follows on 14 MHz:

100W 21A
50W 16A
25W 12A
10W 4A (PA bypassed below 12W)
RX 1A

The current on receive is probably half that of many other transceivers. As shown above, running half power doesn't equal half current. I don't have a meter to hand to check my 480, but the results will be similar. The K3 has built in metering so it easy to check...

You can either run a lower power radio with a small gel cell, or run a 100W radio from a heavy battery.

In answer to your question on radios running from lower than "shack" Voltage, the K3 will deliver 85 Watts from an 11 Volt supply. The 480 gives around 70 Watts.

73 Dave



Thanks so much Dave.

I never intended to run 100w portable - that misconception arose when i commented that i would not be interested in the KX3 without the 100w amp - that was so that i would have the ability to run 100w when needed such as at a beach house, or hooked up to a/c when using it as a backup to my other gear.

Cordially
Don KF7DS
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VE7REN
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Posts: 469




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« Reply #18 on: April 25, 2012, 05:49:51 PM »

i second the ts480sat.................research it and see.
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N6AJR
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Posts: 9915




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« Reply #19 on: April 27, 2012, 10:38:47 AM »

and think about getting a small ( 1 or 2 sq feet size) solar panel.  it may not be enough to power the set but can certainly help keep the battery "up" while using and before and after  the radio use. small  easy to carry and can be working while you are not actually transmiting. like between key downs and at lunch. a half amp of charge  will make a difference.
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KA1MDA
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Posts: 543




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« Reply #20 on: April 27, 2012, 02:20:16 PM »

"You've also got to remember that most battery AH capacity is specified for taking the battery down to about 10VDC. If the radio won't function below say 11.5VDC then you are going to get much less than the rated AH capacity from the battery."

And don't forget, battery capacity is usually based on a C/20 discharge rate! A 100 Ah battery will provide 5A for 20 hours. Raise the discharge rate to 10 or 15 amps, and the capacity goes way down!

Tom, KA1MDA 
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KD8MJR
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Posts: 2181




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« Reply #21 on: April 27, 2012, 03:05:12 PM »

Am I missing something in this post!  Why not use a FT-817D?
You can receive all day with it on a 14ah battery and transmit pretty long also in QRP mode if you want more power just buy a Tokyo HY-Power HL-45B if you can live with 45 watts or a HL-100Bdx if you need 100 watts. Combined this package will still cost a lot less than a KX3.

If i was doing it I would buy the 817D and use the 14Ah battery with that and make a seperate module that had the HL-100Bdx and a larger battery for use on those times when I wont be moving around much.
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VA7CPC
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Posts: 2378




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« Reply #22 on: April 27, 2012, 11:28:47 PM »

Am I missing something in this post!  Why not use a FT-817D?
You can receive all day with it on a 14ah battery and transmit pretty long also in QRP mode if you want more power just buy a Tokyo HY-Power HL-45B if you can live with 45 watts or a HL-100Bdx if you need 100 watts. Combined this package will still cost a lot less than a KX3.


This is a cost/benefit choice that depends on how big the budget is.  Yes, the FT-817 + amp will cost less than a KX3.  But the KX3 is a full digital-IF rig with performance that beats the FT-817 (and most full-size rigs!). 

I own (and love) an FT-817.  Equipped with a narrow filter, it's a decent rig for CW, and does fine for SSB in non-contest conditions (within its power limits).  But it's got analog IF stages, room for one extra filter (there may be a fix for that), no speech compressor, no transmit EQ, no roofing filter, and so on.  It's _not_ a KX3.

          Charles

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W8JX
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« Reply #23 on: April 28, 2012, 05:08:14 AM »

The 817 is long overdue replacement  or serious updating.
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KF7DS
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Posts: 189




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« Reply #24 on: April 28, 2012, 09:26:50 AM »

I am strongly considering the KX3. Thanks for all of the comments.

Best
Don KF7DS
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N3HFS
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Posts: 212




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« Reply #25 on: May 09, 2012, 05:46:29 PM »

Here's another solution, good for the 100W Icom IC-706 and can be modified for other rigs...

http://www.eham.net/reviews/detail/8501
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KF7IPW
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Posts: 47




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« Reply #26 on: May 10, 2012, 12:46:20 AM »

I also am thinking about a KX3 but I really like my Ten-Tecs.
I have a Scout ($350) and an Eagle ($2100) with filters.

The Scout is 5-50 watts and can run most the day on a small battery. Its nice for camping when you worry about mud, kids, dumb banging around etc.

The Eagle is also small, spartan, and can of course be "turned" down to QRP.  It is more of an energy hog. But for the cabin, parks, back deck what could be better?  it's also got a great RCVR.  This would be my choice if you want ONE rig to do it all.  I'm a newbie so take my advice with that in mind.   

The KX3 is just too sexy to pass up though.  I have a piggy bank for that one.  I camp and travel a lot and this will replace the Scout.

Stan

Stan
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