K3 External 2nd receiver with KXV3 and 6m pre-amp?

[Dave, G4AON]

I've just ordered a KXV3 and was pleasantly surprised to find they are
more or less a stock item.

In order to use one with an external receiver simultaneously with the K3
main receiver, it appears necessary to use an external resistive
splitter or better still a hybrid coupler feeding one side back into the
K3 and the other to the external receiver. I wonder if anyone is using
such a set-up and has any thoughts on it. I had rather hoped the RX
output socket was a buffered output from the K3 receive chain but sadly
it isn't.

I also have an Advanced Receiver Products P50VDG 50 MHz pre-amp on order
(http://www.advancedreceiver.com/), again anyone else using one of these
with their K3? It looks easy enough to connect as a direct pre-amp via
the in/out sockets on the KXV3.

73 Dave, G4AON
K3/100 #80
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[Paul Bradbeer]

Dave,

 

I'm not using an external 2nd receiver but I too have gone for an ARR
preamp.  Mine was despatched a week ago, so should be here soon - I went
for the P50VD (i.e. not the Gaesfet one) because I figured I didn't need
so much gain, and the input IP3 figures are very close.  It looks like a
neat mechanical design too.  I'll let you know how I get on..

 

Paul

M0CVX  


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[Jim Brown-10]

On Tue, 29 Jul 2008 05:57:05 +0100, Dave G4AON wrote:

>I also have an Advanced Receiver Products P50VDG 50 MHz pre-amp on order
>(http://www.advancedreceiver.com/), again anyone else using one of these
>with their K3? It looks easy enough to connect as a direct pre-amp via
>the in/out sockets on the KXV3.

I've had one of their auto-switching mast-mount preamps for about five years.
Used it inline with a 746 when I was back in Chicago. It blew up three times
with RF from my HF rigs. Finally got them to add protection diodes to it,
which fixed it. It's now patched into the RX loop of the K3, and works well.

73,

Jim K9YC


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[Jim Brown-10]

On Tue, 29 Jul 2008 17:33:20 +0100, Dave G4AON wrote:

>Hello Jim

>I assume the normal RX loop of the K3 doesn't allow you to add an
>external receiver without making a "Y" lead with either a resistive pad
>or hybrid transformer in the centre? The diagram is hard to follow at
>times, but that is how it looks to me...

The flow isn't at all clear to me either, but Elecraft DOES have schematics on
the website, so we could go look there and figure it out. So far I've had my
mind on other things. :)

>I am hoping to receive the
>interface and pre-amp next week. I will check the RF levels from the K3
>before hooking up the pre-amp.

It's only an issue if the preamp input sees an HF antenna that's receiving lots
of RF. One thing I did was put a good 6M BPF in front of it (I used the ICE unit
that is narrowly tuned to the bottom of 6M). That helped.

>Do you know if AAR include protection diodes as standard now?

I doubt it -- their response to me was rather negative, and they did it only
because I insisted because I was tired of sending it back for warranty repair!
BTW -- mine is also the GasFET version.

73,

Jim


>73 Dave, G4AON

> >/I also have an Advanced Receiver Products P50VDG 50 MHz pre-amp on order
>/>/(http://www.advancedreceiver.com/), again anyone else using one of these
>/>/with their K3? It looks easy enough to connect as a direct pre-amp via
>/>/the in/out sockets on the KXV3.
>/
>I've had one of their auto-switching mast-mount preamps for about five
>years.
>Used it inline with a 746 when I was back in Chicago. It blew up three
>times
>with RF from my HF rigs. Finally got them to add protection diodes to it,
>which fixed it. It's now patched into the RX loop of the K3, and works
>well.

>73,

>Jim K9YC

>No virus found in this incoming message.
>Checked by AVG - http://www.avg.com 
>Version: 8.0.138 / Virus Database: 270.5.6/1579 - Release Date: 7/29/2008 6:43
AM





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[John Klewer]

To enhance the 6 meter performance of my K3 I built the U310
preamplifier as described on N6CA's website:

http://www.ham-radio.com/n6ca/50MHz/50appnotes/U310.html

Tuned up on an HP8970A noise figure meter it gives 11.2 dB gain and
NF=1.3 dB.

The receiver's performance on weak signals was significantly improved. I
already had the parts but cost should not exceed $30.00 to duplicate
this preamp....hard to beat.

I have not done measurements on the radio/preamp combination to
determine any negative effect on the receiver performance but the K3,
which always performed well in the presence of strong signals, continues
to do so.


John, N6AX

K3 #567
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[John Klewer]

Note that I installed this preamplifier in the RX IN/OUT path on the K3
rear panel

> To enhance the 6 meter performance of my K3 I built the U310
> preamplifier as described on N6CA's website:
>
> http://www.ham-radio.com/n6ca/50MHz/50appnotes/U310.html
>
> Tuned up on an HP8970A noise figure meter it gives 11.2 dB gain and
> NF=1.3 dB.
>
> The receiver's performance on weak signals was significantly improved.
> I already had the parts but cost should not exceed $30.00 to duplicate
> this preamp....hard to beat.
>
> I have not done measurements on the radio/preamp combination to
> determine any negative effect on the receiver performance but the K3,
> which always performed well in the presence of strong signals,
> continues to do so.
>
>
> John, N6AX
>
> K3 #567
>

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[n6wg]

Hi John
I've been looking at this circuit for some time.
I have a number of J310s, but no U310s.
Do you know whether they are the same
animal, just in different casings?
73, Bob N6WG

----- Original Message -----
From: "John Klewer" <[hidden email]>
To: <[hidden email]>
Sent: Wednesday, July 30, 2008 10:56 AM
Subject: [Elecraft] Re: K3 6m pre-amp


> Note that I installed this preamplifier in the RX IN/OUT path on the
K3

> rear panel
>
>
>
>
> > To enhance the 6 meter performance of my K3 I built the U310
> > preamplifier as described on N6CA's website:
> >
> > http://www.ham-radio.com/n6ca/50MHz/50appnotes/U310.html
> >
> > Tuned up on an HP8970A noise figure meter it gives 11.2 dB gain

and
> > NF=1.3 dB.
> >
> > The receiver's performance on weak signals was significantly
improved.
> > I already had the parts but cost should not exceed $30.00 to
duplicate
> > this preamp....hard to beat.
> >
> > I have not done measurements on the radio/preamp combination to
> > determine any negative effect on the receiver performance but the
K3,

> > which always performed well in the presence of strong signals,
> > continues to do so.
> >
> >
> > John, N6AX
> >
> > K3 #567
> >
> _______________________________________________
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>
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[Don Wilhelm-4]

Bob,

While I cannot speak from my own measurements, but in EMRFD, Wes Hayward
recommends the U310s for VHF/UHF rather than the J310.  The case of the
U310 is connected to the gate, and when used in a grounded gate
configuration, the case can be mounted (upside down) into a hole in the
PC board, and I believe that alone should provide better input to output
isolation.  The Vishay data sheet indicates a slightly lower noise
figure for the U310.

I would suggest that you try the J310s.  If you find them lacking, it
should be easy to change to U310s, I would guess that at 50 MHz, it may
be a 'toss-up' decision.

73,
Don W3FPR

Bob Tellefsen wrote:
> Hi John
> I've been looking at this circuit for some time.
> I have a number of J310s, but no U310s.
> Do you know whether they are the same
> animal, just in different casings?
> 73, Bob N6WG
>  
>
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[Jack Smith-6]

Don:

The U310's are not too easy to find these days. Vishay seems to be the
most common (only?) new production supplier and the one-off price is
about $14 from Mouser or Arrow.  Digikey, Allied and Newark only stock
the SOT23 plastic surface mount version. TO-92 plastic case parts, the
J310, are around 25 cents each. The U310 and J310 are supposed to have
the same die, so differences should be attributed to the case, but who
knows what goes inside the package these days, particularly if it is
from China.

If I were building a pre-amp based upon a U310, I would start with a
J310 and get it thoroughly debugged before experimenting with U310's at
$14 a pop.

It's something like the 40673 dual gate FET - once ubiquitous and now
difficult to find and expensive when found.


Jack K8ZOA

Don Wilhelm wrote:

> Bob,
>
> While I cannot speak from my own measurements, but in EMRFD, Wes
> Hayward recommends the U310s for VHF/UHF rather than the J310.  The
> case of the U310 is connected to the gate, and when used in a grounded
> gate configuration, the case can be mounted (upside down) into a hole
> in the PC board, and I believe that alone should provide better input
> to output isolation.  The Vishay data sheet indicates a slightly lower
> noise figure for the U310.
>
> I would suggest that you try the J310s.  If you find them lacking, it
> should be easy to change to U310s, I would guess that at 50 MHz, it
> may be a 'toss-up' decision.
>
> 73,
> Don W3FPR
>
> Bob Tellefsen wrote:
>> Hi John
>> I've been looking at this circuit for some time.
>> I have a number of J310s, but no U310s.
>> Do you know whether they are the same
>> animal, just in different casings?
>> 73, Bob N6WG
>>  
> _______________________________________________
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> Post to: [hidden email]
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>

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[Don Wilhelm-4]

Jack,

I understand the vanishing part syndrome.  I have a few remaining in my
parts bin, and I am not about to give them up (similar feelings about my
dual gate MOSFETs).

As an alternative to the U310, when laying out a PC board (or Manhatten
construction board), one might consider the SMD version of the
J310/U310.  It should be at least as good as the U310 and likely
better.  A nice clean layout is critical to performance in a VHF/UHF
amplifier.  A carrier board may be needed for Manhatten construction,
but for 3 legged devices, a carrier board is simplicity itself - just a
tiny scrap of rectangular PC board with the copper cut in half along the
length and one of the remaining long rectangles cut in half across its
width.  Caution - cut the copper on the corner of a larger piece of PC
board and then cut out the result as the 'final act' - attempting to cut
through the copper on a tiny board can result in injury to the fingers
and hands.  With the demise of thru-hole parts and the advent af
inexpensive SMD parts, we hams will have to learn how to deal with these
tiny devices if we are to continue homebrewing and experimenting efforts
at a reasonable price.

73,
Don W3FPR

Jack Smith wrote:

> Don:
>
> The U310's are not too easy to find these days. Vishay seems to be the
> most common (only?) new production supplier and the one-off price is
> about $14 from Mouser or Arrow.  Digikey, Allied and Newark only stock
> the SOT23 plastic surface mount version. TO-92 plastic case parts, the
> J310, are around 25 cents each. The U310 and J310 are supposed to have
> the same die, so differences should be attributed to the case, but who
> knows what goes inside the package these days, particularly if it is
> from China.
>
> If I were building a pre-amp based upon a U310, I would start with a
> J310 and get it thoroughly debugged before experimenting with U310's
> at $14 a pop.
>
> It's something like the 40673 dual gate FET - once ubiquitous and now
> difficult to find and expensive when found.
>
>
> Jack K8ZOA
>

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[Jack Colson]

I personally would use a MGF-1302.

73
Jack, W3TMZ

----- Original Message -----
From: "Jack Smith" <[hidden email]>
To: <[hidden email]>
Cc: <[hidden email]>
Sent: Wednesday, July 30, 2008 6:48 PM
Subject: Re: [Elecraft] Re: K3 6m pre-amp

> Don:
>
> The U310's are not too easy to find these days. Vishay seems to be the
> most common (only?) new production supplier and the one-off price is
> about $14 from Mouser or Arrow.  Digikey, Allied and Newark only stock
> the SOT23 plastic surface mount version. TO-92 plastic case parts, the
> J310, are around 25 cents each. The U310 and J310 are supposed to have
> the same die, so differences should be attributed to the case, but who
> knows what goes inside the package these days, particularly if it is
> from China.
>
> If I were building a pre-amp based upon a U310, I would start with a
> J310 and get it thoroughly debugged before experimenting with U310's
> at $14 a pop.
>
> It's something like the 40673 dual gate FET - once ubiquitous and now
> difficult to find and expensive when found.
>
>
> Jack K8ZOA
>
> Don Wilhelm wrote:
>> Bob,
>>
>> While I cannot speak from my own measurements, but in EMRFD, Wes
>> Hayward recommends the U310s for VHF/UHF rather than the J310.  The
>> case of the U310 is connected to the gate, and when used in a
>> grounded gate configuration, the case can be mounted (upside down)
>> into a hole in the PC board, and I believe that alone should provide
>> better input to output isolation.  The Vishay data sheet indicates a
>> slightly lower noise figure for the U310.
>>
>> I would suggest that you try the J310s.  If you find them lacking, it
>> should be easy to change to U310s, I would guess that at 50 MHz, it
>> may be a 'toss-up' decision.
>>
>> 73,
>> Don W3FPR
>>
>> Bob Tellefsen wrote:
>>> Hi John
>>> I've been looking at this circuit for some time.
>>> I have a number of J310s, but no U310s.
>>> Do you know whether they are the same
>>> animal, just in different casings?
>>> 73, Bob N6WG
>>>
>> _______________________________________________
>> Elecraft mailing list
>> Post to: [hidden email]
>> You must be a subscriber to post to the list.
>> Subscriber Info (Addr. Change, sub, unsub etc.):
>> http://mailman.qth.net/mailman/listinfo/elecraft   Help:
>> http://mailman.qth.net/subscribers.htm
>> Elecraft web page: http://www.elecraft.com
>>
> _______________________________________________
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>
> No virus found in this incoming message.
> Checked by AVG - http://www.avg.com Version: 8.0.138 / Virus Database:
> 270.5.7/1581 - Release Date: 7/30/2008 6:56 AM
>
>
>

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[Jack Smith-6]

I'm using J310 parts in a VLF-LF-MF-HF active antenna design I'm working
on, no need to go to the U310 version at those frequencies.

I've found best intermodulaton performance in the active antenna
requires 25 - 35 mA idle current with 8-10 volts source-drain, so
there's some advantage in rated dissipation with the U310 part.

Another used-to-be-common part is a 2.5 mH RF choke, pi wound on a
ceramic form. After a lengthy search, I found Hammond still makes these,
only to learn that they were discontinued earlier this year. I managed
to get one (at a price of $14) and it's good that I only needed one to
use as a comparison reference for a QEX article I'm working on.

Jack


Don Wilhelm wrote:

> Jack,
>
> I understand the vanishing part syndrome.  I have a few remaining in
> my parts bin, and I am not about to give them up (similar feelings
> about my dual gate MOSFETs).
>
> As an alternative to the U310, when laying out a PC board (or
> Manhatten construction board), one might consider the SMD version of
> the J310/U310.  It should be at least as good as the U310 and likely
> better.  A nice clean layout is critical to performance in a VHF/UHF
> amplifier.  A carrier board may be needed for Manhatten construction,
> but for 3 legged devices, a carrier board is simplicity itself - just
> a tiny scrap of rectangular PC board with the copper cut in half along
> the length and one of the remaining long rectangles cut in half across
> its width.  Caution - cut the copper on the corner of a larger piece
> of PC board and then cut out the result as the 'final act' -
> attempting to cut through the copper on a tiny board can result in
> injury to the fingers and hands.  With the demise of thru-hole parts
> and the advent af inexpensive SMD parts, we hams will have to learn
> how to deal with these tiny devices if we are to continue homebrewing
> and experimenting efforts at a reasonable price.
>
> 73,
> Don W3FPR
>
> Jack Smith wrote:
>> Don:
>>
>> The U310's are not too easy to find these days. Vishay seems to be
>> the most common (only?) new production supplier and the one-off price
>> is about $14 from Mouser or Arrow.  Digikey, Allied and Newark only
>> stock the SOT23 plastic surface mount version. TO-92 plastic case
>> parts, the J310, are around 25 cents each. The U310 and J310 are
>> supposed to have the same die, so differences should be attributed to
>> the case, but who knows what goes inside the package these days,
>> particularly if it is from China.
>>
>> If I were building a pre-amp based upon a U310, I would start with a
>> J310 and get it thoroughly debugged before experimenting with U310's
>> at $14 a pop.
>>
>> It's something like the 40673 dual gate FET - once ubiquitous and now
>> difficult to find and expensive when found.
>>
>>
>> Jack K8ZOA
>>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
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>

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[n6wg]

Don't think I've seen that kind of model number before, Jack.
What is it and who makes it?
Thanks and 73
Bob N6WG

----- Original Message -----
From: "Jack Colson" <[hidden email]>
To: "Jack Smith" <[hidden email]>;
<[hidden email]>
Cc: <[hidden email]>
Sent: Wednesday, July 30, 2008 4:37 PM
Subject: Re: [Elecraft] Re: K3 6m pre-amp

> I personally would use a MGF-1302.
>
> 73
> Jack, W3TMZ
>
> ----- Original Message -----
> From: "Jack Smith" <[hidden email]>
> To: <[hidden email]>
> Cc: <[hidden email]>
> Sent: Wednesday, July 30, 2008 6:48 PM
> Subject: Re: [Elecraft] Re: K3 6m pre-amp
>
>
> > Don:
> >
> > The U310's are not too easy to find these days. Vishay seems to be

the
> > most common (only?) new production supplier and the one-off price
is
> > about $14 from Mouser or Arrow.  Digikey, Allied and Newark only
stock
> > the SOT23 plastic surface mount version. TO-92 plastic case parts,
the
> > J310, are around 25 cents each. The U310 and J310 are supposed to
have
> > the same die, so differences should be attributed to the case, but
who
> > knows what goes inside the package these days, particularly if it
is
> > from China.
> >
> > If I were building a pre-amp based upon a U310, I would start with
a
> > J310 and get it thoroughly debugged before experimenting with
U310's
> > at $14 a pop.
> >
> > It's something like the 40673 dual gate FET - once ubiquitous and
now

> > difficult to find and expensive when found.
> >
> >
> > Jack K8ZOA
> >
> > Don Wilhelm wrote:
> >> Bob,
> >>
> >> While I cannot speak from my own measurements, but in EMRFD, Wes
> >> Hayward recommends the U310s for VHF/UHF rather than the J310.

The
> >> case of the U310 is connected to the gate, and when used in a
> >> grounded gate configuration, the case can be mounted (upside
down)
> >> into a hole in the PC board, and I believe that alone should
provide
> >> better input to output isolation.  The Vishay data sheet
indicates a
> >> slightly lower noise figure for the U310.
> >>
> >> I would suggest that you try the J310s.  If you find them
lacking, it
> >> should be easy to change to U310s, I would guess that at 50 MHz,
it

> >> may be a 'toss-up' decision.
> >>
> >> 73,
> >> Don W3FPR
> >>
> >> Bob Tellefsen wrote:
> >>> Hi John
> >>> I've been looking at this circuit for some time.
> >>> I have a number of J310s, but no U310s.
> >>> Do you know whether they are the same
> >>> animal, just in different casings?
> >>> 73, Bob N6WG
> >>>
> >> _______________________________________________
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Database:

> > 270.5.7/1581 - Release Date: 7/30/2008 6:56 AM
> >
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[K7TV]

Try Antique Electronic Supply (www.tubesandmore.com).
Their 2.5 mH is good for 160 mA, made by Hammond,
core material is ferrite, 3 pi-windings, diameter 0.469", price
$3.95.

Erik K7TV


>Another used-to-be-common part is a 2.5 mH RF choke, pi wound on a
>ceramic form. After a lengthy search, I found Hammond still makes these,
>only to learn that they were discontinued earlier this year. I managed
>to get one (at a price of $14) and it's good that I only needed one to
>use as a comparison reference for a QEX article I'm working on.

[Jack Smith-6]

Yes, I have several ferrite core 2.5 mH chokes here, including the
Hammond one you mention. There's a significant difference in high
frequency performance of the pi wound on ceramic form versus the smaller
pi-wound over ferrite and that's one of the things I'm hoping to
illustrate in the article. Hence, I needed a genuine 2.5 mH "National
Radio" style choke.

Jack


K7TV wrote:

> Try Antique Electronic Supply (www.tubesandmore.com).
> Their 2.5 mH is good for 160 mA, made by Hammond,
> core material is ferrite, 3 pi-windings, diameter 0.469", price
> $3.95.
>
> Erik K7TV
>
>
>  
>> Another used-to-be-common part is a 2.5 mH RF choke, pi wound on a
>> ceramic form. After a lengthy search, I found Hammond still makes these,
>> only to learn that they were discontinued earlier this year. I managed
>> to get one (at a price of $14) and it's good that I only needed one to
>> use as a comparison reference for a QEX article I'm working on.
>>    
>
>
>  

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[Ken Kopp-3]

Good grief ... why us old poops hoard stuff ... I have a cigar box
of 'em!  Come to think of it, having cigar boxes dates me.  (:-))

73! Ken Kopp - K0PP
     [hidden email]
     K2 #5665
     K3 #56
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[Jan Erik Holm]

Or BF981 would work nicely. However don´t know how hard to
get they are these days.
A preamp with NF below 1 can easily be built with a BF981,
forexample the YU1AW cavity design with BF981.

73 Jim SM2EKM
-------------------------

Jack Colson wrote:

> I personally would use a MGF-1302.
>
> 73
> Jack, W3TMZ
>
> ----- Original Message ----- From: "Jack Smith"
> <[hidden email]>
> To: <[hidden email]>
> Cc: <[hidden email]>
> Sent: Wednesday, July 30, 2008 6:48 PM
> Subject: Re: [Elecraft] Re: K3 6m pre-amp
>
>
>> Don:
>>
>> The U310's are not too easy to find these days. Vishay seems to be the
>> most common (only?) new production supplier and the one-off price is
>> about $14 from Mouser or Arrow.  Digikey, Allied and Newark only stock
>> the SOT23 plastic surface mount version. TO-92 plastic case parts, the
>> J310, are around 25 cents each. The U310 and J310 are supposed to have
>> the same die, so differences should be attributed to the case, but who
>> knows what goes inside the package these days, particularly if it is
>> from China.
>>
>> If I were building a pre-amp based upon a U310, I would start with a
>> J310 and get it thoroughly debugged before experimenting with U310's
>> at $14 a pop.
>>
>> It's something like the 40673 dual gate FET - once ubiquitous and now
>> difficult to find and expensive when found.
>>
>>
>> Jack K8ZOA
>>
>> Don Wilhelm wrote:
>>> Bob,
>>>
>>> While I cannot speak from my own measurements, but in EMRFD, Wes
>>> Hayward recommends the U310s for VHF/UHF rather than the J310.  The
>>> case of the U310 is connected to the gate, and when used in a
>>> grounded gate configuration, the case can be mounted (upside down)
>>> into a hole in the PC board, and I believe that alone should provide
>>> better input to output isolation.  The Vishay data sheet indicates a
>>> slightly lower noise figure for the U310.
>>>
>>> I would suggest that you try the J310s.  If you find them lacking, it
>>> should be easy to change to U310s, I would guess that at 50 MHz, it
>>> may be a 'toss-up' decision.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> Bob Tellefsen wrote:
>>>> Hi John
>>>> I've been looking at this circuit for some time.
>>>> I have a number of J310s, but no U310s.
>>>> Do you know whether they are the same
>>>> animal, just in different casings?
>>>> 73, Bob N6WG

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[Jan Erik Holm]

Oh well a cavity design might not be the way to go on 6m,
it might get a bit too big when I think about it.
A very low NF isn´t needed in the first place. There are
a ton of transistors that can be used, after all it´s
only 50 MHz.

/SM2EKM
--------------
Jan Erik Holm wrote:
> Or BF981 would work nicely. However don´t know how hard to
> get they are these days.
> A preamp with NF below 1 can easily be built with a BF981,
> forexample the YU1AW cavity design with BF981.
>
> 73 Jim SM2EKM
> -------------------------
>

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[Jan Erik Holm]

MGF1302 is a GaSFet transistor. Used to be popular in preams
on 144/432 MHz amongst EME´ers.

A device like that is far from needed on 50 MHz also since
the MGF1302 is designed for a much higher frequency it actually
might not be a good deal to use it on 50 MHz.
I would stay away from GaSFet´s and Dual Gate MosFet´s on
50 MHz, not needed.
A 2N5109 might be a good deal.

/ de SM2EKM
----------------

Bob Tellefsen wrote:

> Don't think I've seen that kind of model number before, Jack.
> What is it and who makes it?
> Thanks and 73
> Bob N6WG
>
> ----- Original Message -----
> From: "Jack Colson" <[hidden email]>
> To: "Jack Smith" <[hidden email]>;
> <[hidden email]>
> Cc: <[hidden email]>
> Sent: Wednesday, July 30, 2008 4:37 PM
> Subject: Re: [Elecraft] Re: K3 6m pre-amp
>
>
>> I personally would use a MGF-1302.
>>
>> 73
>> Jack, W3TMZ
>>

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[n6wg]

Yes, I have a number of 2N5109s.  I use them
in my HF preamps.
Thanks, Jan Erik.
73, Bob N6WG

----- Original Message -----
From: "Jan Erik Holm" <[hidden email]>
Cc: <[hidden email]>
Sent: Thursday, July 31, 2008 4:38 AM
Subject: Re: [Elecraft] Re: K3 6m pre-amp

> MGF1302 is a GaSFet transistor. Used to be popular in preams
> on 144/432 MHz amongst EME´ers.
>
> A device like that is far from needed on 50 MHz also since
> the MGF1302 is designed for a much higher frequency it actually
> might not be a good deal to use it on 50 MHz.
> I would stay away from GaSFet´s and Dual Gate MosFet´s on
> 50 MHz, not needed.
> A 2N5109 might be a good deal.
>
> / de SM2EKM
> ----------------
>
> Bob Tellefsen wrote:
> > Don't think I've seen that kind of model number before, Jack.
> > What is it and who makes it?
> > Thanks and 73
> > Bob N6WG
> >
> > ----- Original Message -----
> > From: "Jack Colson" <[hidden email]>
> > To: "Jack Smith" <[hidden email]>;
> > <[hidden email]>
> > Cc: <[hidden email]>
> > Sent: Wednesday, July 30, 2008 4:37 PM
> > Subject: Re: [Elecraft] Re: K3 6m pre-amp
> >
> >
> >> I personally would use a MGF-1302.
> >>
> >> 73
> >> Jack, W3TMZ
> >>
>
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