Amp Suggestions

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  • Question
  • Updated 2 years ago
  • Answered
I have a FLEX-6500, 43' vertical, looking to possibly add and AMP this year.  This will be my first amplifier so excuse all the questions.

I want to run the amp from 120 volts (possibly switch it to 240 in the future if possible)
I think I want a linear amp (suggestions)
Not necessary to go full legal limit (think 1000 watts will be plenty)

So, what are you experiences with Amps that work well with these Flex radio's?

I thought I read somewhere FLEX is looking to make an amp, what is the latest info on that?


Thanks

David
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David Warnberg

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Posted 3 years ago

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WA2SQQ

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I use an Acom 1000. Incredible buy for the price. I think it can be rewarded for 120. No regrets buying it. Reliable, covers 160-6 and very easy to tune up. It also tolerates SWR up to 3:1.
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Ronald / W4RJF

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I run an Acom 1000 on 120...work's great with the Flex 6300...
(Edited)
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wg c

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Most likely just about anything will work, but the ACOM 1000 is the way to go.  160-6 for the $$ is the way to go.  Sure you have to tune it but it's like the good ole days!
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Rob N4GA

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I built my own LDMOS solid state amp. It's awesome. Nicest amp I've ever owned..

:)
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WA2SQQ

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Acom is a super easy interface to my 6500
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Jim Gilliam

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http://www.elecraft.com/KPA500/KPA500.htm


Can't go wrong with this one.

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David Warnberg

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Jim.. want to speak with you more regarding the elecraft amp..

Look me up on qrz and send me an e-mail please... KK4QOE

Basically am looking at the KPA-500 and the KAT-500.. I run DDutil and am curious if it will setup to follow the radio.. i.e. band change, auto tune, etc....
(Edited)
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Rob Fissel

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David, same setup. The KPA/KAT 500. With ddutil it's like having a 500w rig, auto antenna switching no tune. Works great when I'm running remote which was a big get for me. Full 500w out for digi (think RTTY and FSK441/JTMSK. PULL THE TRIGGER!
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David Warnberg

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Thanks rob.. ordered the kat500 first to test with but this sounds promising
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David Warnberg

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Trigger pulled... :-)
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KF4HR

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I use an ICOM PW-1.  It works fine and my Flex-6700 easily drives it to 1kw output.  I've read other Flex users are successfully using the Expert line of amps as well (1k, 1.3k, 2k).  I'm planning on selling my PW-1 and upgrading to a 2K-FA eventually.

If you run a 1000w amp on 120vac, and plan to run full power, I recommend using a dedicated 120vac 20A circuit, as the 120vac circuit you choose may have other loads (lights, radio equipment, etc).  If you don't have a dedicated 120vac 20A circuit another option is to limit the output power of the amplifier.       
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Mal G3PDH

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Reference driving your pw1 from 6700, have you managed to interface with its CIV for automatic band switching of the PW1?
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KY6LA - Howard, Elmer

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I used to with DDUTIL. But have a 2K-FA now
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Roy Laufer

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What about the SPE 1.3K-FA? It's so popular that it is still on backorder with the manufacturer. It's small and light and very energy efficient.
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Reg

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I have an ALPHA 9500 and an SPE 1.3K-FA.  They are both supported by DDUtil.  On 110V the 1.3K-FA will put out a solid 900W.
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K1UO - Larry

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You might look at the SPE1Kfa amp also.  Solid state, fully automatic 160-6 meters and has its own built in antenna tuner.  As KF4HR said above..If you use it on 120V circuit then put it on its own dedicated 20A circuit.   The SPE1k is more readily available new and used and might also be available from some Dealers who took trade ins for Amp upgrades.
(Edited)
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Simon Lewis

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Have an SPE1K brilliant amp linear PSU if you dont need to worry about weight

1150w on 20 key down

never misses a beat work a lot of dx

instant on n ready ...tuner etc great

def would buy another

cheers

Simon
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Delbert McCord

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I now have 2 Flex 6300 and I run a Ameritron AL-600 on both of them. I had the amps before i upgraded to the Flex and have not had any problem with them. Yes they are only 600 watts but I also have a AL-1200 I used for a little while and I would switch back and forth with the same antenna and band conditions. Unless you are trying to bust a pile up there is not much difference on the receiving end between 600 and 100 watts. I know they are not the highest quality or priced amps and I purchased both of mine used for around the 600$ mark but they have served me well. If I was going to run much more than 600-800 watts I would take the time to put in a 220 circuit. I did that for the Al-1200 I do not think it would have worked on a 115 volt circuit, at lease not well. 
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Walt - KZ1F

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I ha e an Elecraft kpa-500 and kat500. It is nominally 500w but can easily do 650w and above. It's a fantastic linear and runs fine on 115v but is switchable to 230v should you want to.
(Edited)
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AE0MW

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You're a brave man, I've never tried to drive my KPA-500 that hard!
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Doug Hall

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The KPA-500 is a rugged little beast, including the PA transistors. It'll protect itself from just about any injustice inflicted upon it. The TX IMD suffers at the higher power levels, however.
73,
Doug K4DSP
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Barry N1EU

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The TX IMD suffers at the higher power levels, however.
Nothing that a little adaptive pre-distortion couldn't fix.

73, Barry N1EU
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David Warnberg

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Walt, I'm seriously considering this combo.. KPA-500 and KAT-100... I've heard nothing but good things about elecraft in general, I dont have to mod the amp for MARS operation, not sure I need 2 bagillion watts been happy with 100 or less up till this point and once in a while needing a little extra boost.. 

I've considered several:
1) ACOM600S
2) Elecraft KPA-500/KAT-100 combo
3) Expert 2K-FA (only real option from them)
4) ACOM 1000

Decisions decisions.. 
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Ian GM4KLN

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Hi David
It may be useful to consider what modes you like to operate, as that defines the duty cycle: I like to run digital modes such as RTTY, JT9, JT6m etc. and these are harder on the amp (I have the excellent Acom 1000) but it strolls along at 350 watts or so.....matched to my 6300. 
Think too whether you want valves or solid state; manual or auto-tune. do you want 50 MHz too? built in ATU?  and so on. 
in other words...have a think about what your needs are now, and could grow to be..and then look for a match. I'm sure many of the main candidates have already been proposed....
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David Warnberg

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Well.. I was not going to use the amp when using digital modes (JT65, JT9, RTTY, PSK31, etc...) I don't see the need to in those modes, I can easily make contacts now in JT9 or JT65 with 15 watts or less.  

Mainly the amp would be used for SSB Voice.. I am finding I can hear stations easily yet they can't always hear me (I equate this to the superior receive abilities of the FLEX 6500) 

As far as tuners are concerned, I have the ATU in the 6500 as well as a separate Palstar AT2K.  So a built in tuner in the Amp is optional to me, but for quick band switching (Chasing DX) the built in tuner would be of great benefit. 

I currently don't really do much with 6 meters, however there is always the possibility that when I retire (yes thinking about retirement finally) I plan on property where I can have the antenna to be able to work 6 meters as well, right now I'm limited... 

Thanks 
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Steve (N9SKM)

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I run an Acom 1000 and like it and have a remote tuner for the antenna (also running a 43 foot vertical due to QTH) I love the tuning indicator on the amp and the protection that Acom has built in. As others have said if you run it on 120 you still really need to have a dedicated service for it so you may as well run 240.
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Ross - K9COX

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To quote a line from the National Lampoon's Vacation movie "How much you got".
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David Warnberg

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That will depend on bonus..   but not thinking that will be much of an issue, it's when the wife finds out how much I spent is the issue...   HEHEHEHE
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Jim Gilliam

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Brain washing wives is something that should be part of the learning curve of developing yourself as an A-1 amateur.
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David Warnberg

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I'm kinda bummed, ACOM doesn't have a booth at Hamcation... Expert Amps does though....
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Tony C kc2dis

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I use a ameritron al 80 b. This is my first amp. Works great. I cant seem to figure out the hardware alc thing. But it has been a wonderful am so far...
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Ken - WA8JXM

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Good comments so far. At the lower end of the price spectrum, I bought a used Heathkit SB-1000 ($700 on eBay.)  It works well with the Flex 6300 on SSB and CW (rarely need it on CW), runs on  110v and makes a worthwhile difference when conditions are difficult.  

If you are using a vertical, make sure you have plenty of radials.
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Jim Gilliam

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ALC is a circuit that senses when the amplifier is overdriven and sends information back to the transceiver/tranmitter to reduce its output. It is used to protect the amplifier from too much drive and to reduce distortion.
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KY6LA - Howard, Elmer

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I have an SPE 2K-FA at Home and we use ACOM and ALPHA's at the Contest Station.

The 2K-FA will key down about 2300W into a dummy load all day and keep on ticking.. It is almost completely idiot proof, it is instant ON -  Definitely my preferred AMP especially when I am remote because it is idiot proof...and I sometimes do idiot things 10,000 miles away...

The ACOM's and ALPHA'a are HOT.. Quite Noisy...Take 3-4 minutes to warm up and use very expensive tubes that need to be replaced regularly (if you abuse them in contesting) and likely will become unobtanium....They do produced better IMD than does the Solid State Amps. but not that significant in contests as the other guys will copy the crappiest signal for a Q

I personally prefer that Autotuning Amps - my first Amp was the first autotuning Alpha 374 (Serial #1) i bought in 1974 which spoiled me for autotuning amps forever...   My first Solid State Amp was a PW-1 - which spoiled me for solid state amps forever... Nothing like QUIET, Instant On, Instant OFF, COOL Running Solid State Amps for operator comfort.

Ultimately it depends how much $$$ you are prepared to spend.  Almost any amp will do something for you  (Life is far too SHORT for QRP)....

Heatkits are long at the tooth but proven reliable IF they were asssembled by someone who knew what they were doing..The Ameritron Amps work.. their quality is questionable and I would not want to depend on one for a contest...  It's a toss up between the Alpha and ACOM.. Alpha is USA Made (?).. ACOM is a clone but less expensive..  The 500W Elecraft is cute but like a Smart Car.. why would anyone want to drive a small thing like that..  The PW-1 is getting pretty long at the tooth for a Solid State Amp... There are a few Yaesu Quadra's around.. good solid performer for a 20 year old design but crappy interface...The current hottest AMP on the market is the SPE 1.3K... same features are the 2K but 60% of the power in by far the lightest and smallest package.. it is easily the favorite of DXpeditions..

Dayton,. Being Dayton.. if you can wait until May.. who knows what 4A3O and Flex may announce....
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KY6LA - Howard, Elmer

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Mine was the Export Version with 3 tubes. 3KW. Could not be sold in the USA. So I did Dick Ernhorn a favor at Dayton 1974 by exporting it out if the USA so he would not have to return it to the factory to remove a tube so it would be USA legal.
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KY6LA - Howard, Elmer

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SPE USA. Is http://expertlinears.com now. Very much alive.
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KY6LA - Howard, Elmer

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A SMart Cart Costa a lot less than a real car, runs on regular and can almost hit the speed limit.

But I still can't imagine owning one.
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Ross - K9COX

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Now Howard, are you implying that some hams run more than the legal limit? Have you removed the tags from your pillows?
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KY6LA - Howard, Elmer

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It's very nice to have lots of headroom when running 100% duty cycle modes.

But for me at least it's no fun or challenge winning anything by cheating
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Lee, Elmer

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I think an AL80B is the best bang for the buck amp in America.  With a 43ft vert you likely will need a KW tuner also.   

73  W9OY
(Edited)
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Walt

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A nice DX-3SP from Emtron in Sidney will not let you down.  Even though it will do 4KW CW, you would, of course, reduce the power to meet legal limits.  And the tubes would last a long time (smirk).

Just make sure your dipole is made from #8 wire as a minimum .   #2 would be better . . . . 
If you hear them, you will work them . . .

Cheers
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David Warnberg

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Ok, so I went shopping and looked lots at Hamcation.. now here is the question.. of the amps you guys listed how many will work on the MARS frequencies... i.e. outside of the HAM bands???  I know that the Elecraft will out of the box (asked and confirmed), the Expert Amps will with mods (they only suggest the big boy 2K-FA), others just flat say NO..

David
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Rob N4GA

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My home brew LDMOS will TX anywhere with no tuning. 1-60Mhz, at least.

:)
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Rob N4GA

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Thanks John. I'm looking at much nicer enclosures now. I'm a function over form guy but the function is now proven, so nothing wrong with improving the form at this point.
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Joe WD5Y

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I built a two module blf188xr amp that covers 160 through 54 MHz. It has complete filtering, protection for wrong band selection and antenna swr. It has auto or manual band selection with BCD circuitry that works with ddutil or other band selection input. Also, ALC feedback to flex, control board functions. It is totally remoteable as well. I have some photos on qrz. I built this from kits purchased from W6PQL. The amp is well protected, I did add a different method for selection of auto /manual band selection of filtering. W6PQL offers many kits or completed units.

73's
Joe
WD5Y

Rob,
Looked at your build really looks great! I am attaching a photo of my build.

73's
Joe
WD5Y
(Edited)
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KC2QMA_John

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Yes James W6PQL is a genius. I wonder what his legal limit amp cost as a kit or assembled?

Since these devices only require 50V  and run extremely cool My guess is in the future we will see a Transceiver with one of these built in! Imagine a Flex 7000 series with 1200W built right in. Well we can dream can’t we? ;)

Looking Good Joe

73’KC2QMA

(Edited)
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Joe WD5Y

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W6PQL just came out with a transverter control unit for the flex, looks good. I believe a one module amp is around $3,000 built. I plan to put more photos on my qrz page when possible. I actually worked on the amp for approximately five to six months on and off. I did upgrade the combiner and directional coupler circuits (load protection circuits before and after LPF filtering), this was beefed up even more. The ALC works very good with the flex.

Thanks,
Joe
WD5Y
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Rob N4GA

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Joe - nice amp! Send me an email or txt if you would. Want to ask you a few questions. rob.mccance@gmail.com or 7703667535

Thank you
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Dave KD5FX

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Ya know, a vertical radiates equally poor in all directions, instead of an amp have you thought about a beam antenna that would boost your ERP and work equally well on boosting your receive signal? 
http://www.k4kio.com/hexbeam-vs-vertical/
73, Dave KD5FX
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Lee, Elmer

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which hex beam covers mars freqs?

73  W9OY
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David Warnberg

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Dave, unfortunately I'm stuck... HOA, need I say more??  I have been lucky to this point with a 43' flag pole in the back corner of my yard with no flag on it...

Lee there is a new hex out that covers through 160 meters.. it's HUGE, 21 or 22' across I believe.. saw it at hamcation, they say it will cover MARS frequencies
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Al / NN4ZZ

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Dave & Lee,
Two of my HexLock  customers the 160-10 hexbeam.  Pictures and a link to the vendors page here:

http://www.nn4zz.com/hexlock%20customer%20pictures.html

Regards, Al / NN4ZZ  
al (at) nn4zz (dot) com
6700 - HW.................... V 1.6.21.77
SSDR / DAX / CAT...... V 1.6.21.159
Win10
 
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David Warnberg

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All, just wanted to say thank you for all the suggestion's... I shopped and researched and finally decided on the Elecraft KAT-500 KPA-500 combination.

I can report at this time everything is together and working better then expected.  First call replies are now the norm.

Thanks Again

David
KK4QOE
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Peter K1PGV, Elmer

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Just to update this thread from a month ago:

I've also recently started considering an amp/tuner combo.  To make a long story short, the lead-time for the SPE 1.3K-FA is currently projected to be just a bit less than ONE YEAR (this, according to Bob Hardie of Expert Linears).  And that's a projection, not a guarantee.  The cost, with tuner, is about US$5K, including CONUS shipping.

The KPA/KAT combo ships more or less from stock, and costs about US$3K.  And while the technology isn't really quite as cool as the SPE, it's probably more of in the range of power that I'd use.  I'm really not a full kilowatt kind of guy.

So... that's the latest update.

Peter
K1PGV

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AE0MW

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Rob, absolutely NOT set up to be on the go. Although everything is attached fairly well to the shelves, the racks only have front posts so there is no rear support. I like it for the clean installation and appearance. Not to mention fragility of components, excessive weight, or amazing cost of the contents of that rack.

I don't personally see the "Flex model" of SDR as a viable portable station. I've given a good deal of thought to what would get me to purchase a "portable Flex" and a product could be made, but right now it's not in Flex's lineup. I have a KX-3 for portable use that works great.

Anyway, the rack was custom made by NovexComm , based on their K3 rack and extended to have the KAT-500 sit on top. We had some problems with their aluminum shelf holding the weight of the KPA-500 but I talked it over with them and we added some U channel stiffeners across the shelf near the front and rear feet to solve the problem. I highly recommend NovexComm, they really went the extra mile to accommodate my request and their prices were reasonable.
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Mark - W6MSB

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Roy -- which LDG tuner are you using??
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Roy Laufer

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I am using the LDG AT-1000ProII. It has some problems recognizing high SWR on 28.380MHz, but generally it has performed well.

If I had it to do all over again, this time I might have chosen an MFJ-998 - It seems a bit more "polished" with a more informative display (you just have to play "Russian Roulette" with MFJ's poor excuse for Quality Control).
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Mark - W6MSB

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Thanks for your response. Rookie question -- can the LDG AT-1000ProII handle the full 1300 watts from the amp? I get that it's probably not a full 1.3K, but you haven't seen any problems?

I have the same concern with MFJ products. No regrets on not getting the internal tuner?
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Roy Laufer

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I have not regretted not getting the built-in tuner - I saved $1K and my fan dipole needs more than a tuner designed for 3:1 SWR correction.

The trouble with antenna tuners is that their actual power rating depends to a degree on what the SWR is that they are correcting and the amount and kind of impedance they are using to get near to 1:1. The LDG has published ratings of 1,000W SSB PEP, the MFJ has published ratings of 1,500W. Perhaps there is a difference in design that allows for more power handling, perhaps it is just the marketing department being creative...

When I chose the LDG it had the widest match range 1:10 (the MFJ model was a dream in a circuit designer's mind). I figured that the SPE was designed for 1.3KW at most, so I would try not to pour on full power until I got very comfortable with my present setup.

I haven't tried to max out my SPE 1.3K yet  I'm waiting for a LP-500 to evaluate linearity and distortion parameters.