Elecraft › [K3]

K3 and Alpha 91b

Classic

List

Threaded

5 messages Options

N9QR

K3 and Alpha 91b

I have an Alpha 91b hooked to the K3 (SN 8376) and I'm having an "Odd"
problem ... on 75/80 meter SSB, if I run the amp at 45 watts, which is what
works on CW without issue, I encounter significant nuisance tripping of the
Amplifier to the fault condition. The amp also exhibits a power spike into
the 2KW range often times when it faults. If I reduce the power to 30
watts on the K3, the amp runs 1500 watts OK without tripping. Please ....
resist the temptation to say "Run at 30 watts then". All other bands ...
except 6 meters which I didn't check, do not exhibit this issue. Power out from
the K3 is 45 watts and the amp runs 1500 watts out with NO nuisance
tripping. I've talked to the tech's at Alpha and at least one other K3 owner
has had this same problem. He asked me to check the amp with another radio
so, using my spare radio, Yaesu FT-450, to drive the amp I have no nuisance
tripping on any band while running 45-50 watts into the amp. Neither radio
has ALC hooked up, only the TR relay. Both radios and amp are grounded to
the same ground buss. RF calibration was done when the radio was
assembled and I have not re-done that process.

Any ideas as to why the radio would exhibit a tendency to over drive the
amp just on 75/80 meters?

Mike N9QR
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Mike Stover

Re: K3 and Alpha 91b

OOPS ... K3 SN is 3786 ... senior moment!

Mike N9QR

From: [hidden email]
Date sent: Tue, 19 Jan 2010 15:59:45 EST
To: [hidden email]
Subject: [Elecraft] K3 and Alpha 91b

> I have an Alpha 91b hooked to the K3 (SN 8376) and I'm having an
> "Odd"
> problem ... on 75/80 meter SSB, if I run the amp at 45 watts, which
> is what
> works on CW without issue, I encounter significant nuisance tripping
> of the
> Amplifier to the fault condition. The amp also exhibits a power
> spike into
> the 2KW range often times when it faults. If I reduce the power to
> 30
> watts on the K3, the amp runs 1500 watts OK without tripping.
> Please ....
> resist the temptation to say "Run at 30 watts then". All other
> bands ...
> except 6 meters which I didn't check, do not exhibit this issue.
> Power out from
> the K3 is 45 watts and the amp runs 1500 watts out with NO
> nuisance
> tripping. I've talked to the tech's at Alpha and at least one
> other K3 owner
> has had this same problem. He asked me to check the amp with
> another radio
> so, using my spare radio, Yaesu FT-450, to drive the amp I have no
> nuisance
> tripping on any band while running 45-50 watts into the amp.
> Neither radio
> has ALC hooked up, only the TR relay. Both radios and amp are
> grounded to
> the same ground buss. RF calibration was done when the radio was
> assembled and I have not re-done that process.
>
> Any ideas as to why the radio would exhibit a tendency to over drive
> the
> amp just on 75/80 meters?
>
> Mike N9QR
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list:
> http://www.qsl.net/donate.html

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

K1LI

Re: [Elecraft] K3 and Alpha 91b

In reply to this post by N9QR

Mike,

I have used my K3 and A91b successfully on all bands from 160 through 10
meters for over a year. No problems with SSB on any bands. I have run full
output on 160 and 80/75, both SSB and CW. Net: I can't think why you're
having trouble.

I do have one problem on the low bands that I do not associate with the K3
but might be playing into your situation somehow. I believe my house wiring
is picking up RF, which kills my DSL connection whenever I run high power on
160 and sometimes when I only run 100W barefoot from the K3.

Have you run the setup into a dummy load?

Brian K1LI

On Tue, Jan 19, 2010 at 3:59 PM, <[hidden email]> wrote:

> I have an Alpha 91b hooked to the K3 (SN 8376) and I'm having an "Odd"
> problem ... on 75/80 meter SSB, if I run the amp at 45 watts, which is what
> works on CW without issue, I encounter significant nuisance tripping of the
> Amplifier to the fault condition. The amp also exhibits a power spike into
> the 2KW range often times when it faults. If I reduce the power to 30
> watts on the K3, the amp runs 1500 watts OK without tripping. Please ....
> resist the temptation to say "Run at 30 watts then". All other bands ...
> except 6 meters which I didn't check, do not exhibit this issue. Power
> out from
> the K3 is 45 watts and the amp runs 1500 watts out with NO nuisance
> tripping. I've talked to the tech's at Alpha and at least one other K3
> owner
> has had this same problem. He asked me to check the amp with another
> radio
> so, using my spare radio, Yaesu FT-450, to drive the amp I have no
> nuisance
> tripping on any band while running 45-50 watts into the amp. Neither
> radio
> has ALC hooked up, only the TR relay. Both radios and amp are grounded to
> the same ground buss. RF calibration was done when the radio was
> assembled and I have not re-done that process.
>
> Any ideas as to why the radio would exhibit a tendency to over drive the
> amp just on 75/80 meters?
>
> Mike N9QR
>

Mike Stover

Re: [Elecraft] K3 and Alpha 91b

Hi Brian,

Thanks for the feedback ...

I've had no issues with the 91b except for this oddity since I
acquired it about three weeks ago. I previoulsy owned a 91b and an
87a but ended up selling the 91b to a friend along with a Collins S
Line. I sold the 87a (HUGE mistake) and bought a Quadra when I
slimmed down my radio "collection" to a Yaesu FT-1000MP MK V and a
portable FT450 a couple of years ago. I sold the FT-1000 last
December and bought the K3. After I assembled it and got it on the
air, the Quadra became a bit of a pain to deal with because of the
way it senses RF to switch bands (No Data Cables to run between K3
and the Amp) and the extra buttons that had to be pushed on the amp
to switch the bands and tune the amp. So I traded it to a friend for
his
91b. Not sorry I did that at all but this oddity with 80 meter SSB
is
bothering me. I am running 30 watts and getting the 1500 out but I
should
not have to when all other bands, including 160, take 45 watts to
achieve
1500 out into a matched antenna or a dummy load.

As to RFI issues, I have a pretty good ground system ... copper water
pipes and a city water system that is copper all the way to the
street 300
feet away. With in-line traps between the radio and amp and between
the
tuner and the antenna the only issue I have is on 10 meters when I do
get
into the TV and Phone if I run anything over 600 watts ... I think
it's
more antenna proximity that RFI but I'm still working on that.

I use filters on all the phones ... you might try that. Before
Verizon switched me to fibre optic cable I was on a residential DSL
line and I was forced to use band pass filters on all the phones in
the house to keep 80, 10 and 15 meters out of the system at any power
setting over 500 watts. I did discover a ground cable issue when I
was
moving the station around after getting the K3 that may have
contributed
to that however. I run all grounds to a single point with all
radios,
computers, amplifiers and accessory equipment having separate ground
cables to that point. Loose connections and AC wiring without chokes
still pop up as issues occasionally due to my missing something.

73, Mike N9QR

Date sent: Wed, 20 Jan 2010 10:06:08 -0500
From: Brian Machesney <[hidden email]>
To: Elecraft Reflector <[hidden email]>
Subject: Re: [Elecraft] K3 and Alpha 91b

> Mike,
>
> I have used my K3 and A91b successfully on all bands from 160
> through 10
> meters for over a year. No problems with SSB on any bands. I have
> run full
> output on 160 and 80/75, both SSB and CW. Net: I can't think why
> you're
> having trouble.
>
> I do have one problem on the low bands that I do not associate with
> the K3
> but might be playing into your situation somehow. I believe my house
> wiring
> is picking up RF, which kills my DSL connection whenever I run high
> power on
> 160 and sometimes when I only run 100W barefoot from the K3.
>
> Have you run the setup into a dummy load?
>
> Brian K1LI
>
> On Tue, Jan 19, 2010 at 3:59 PM, <[hidden email]> wrote:
>
> > I have an Alpha 91b hooked to the K3 (SN 8376) and I'm having an
> "Odd"
> > problem ... on 75/80 meter SSB, if I run the amp at 45 watts,
> which is what
> > works on CW without issue, I encounter significant nuisance
> tripping of the
> > Amplifier to the fault condition. The amp also exhibits a power
> spike into
> > the 2KW range often times when it faults. If I reduce the power
> to 30
> > watts on the K3, the amp runs 1500 watts OK without tripping.
> Please ....
> > resist the temptation to say "Run at 30 watts then". All other
> bands ...
> > except 6 meters which I didn't check, do not exhibit this issue.
> Power
> > out from
> > the K3 is 45 watts and the amp runs 1500 watts out with NO
> nuisance
> > tripping. I've talked to the tech's at Alpha and at least one
> other K3
> > owner
> > has had this same problem. He asked me to check the amp with
> another
> > radio
> > so, using my spare radio, Yaesu FT-450, to drive the amp I have
> no
> > nuisance
> > tripping on any band while running 45-50 watts into the amp.
> Neither
> > radio
> > has ALC hooked up, only the TR relay. Both radios and amp are
> grounded to
> > the same ground buss. RF calibration was done when the radio
> was
> > assembled and I have not re-done that process.
> >
> > Any ideas as to why the radio would exhibit a tendency to over
> drive the
> > amp just on 75/80 meters?
> >
> > Mike N9QR
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list:
> http://www.qsl.net/donate.html

Roy Morris-6

Re: [Elecraft] K3 and Alpha 91b

In reply to this post by N9QR

Mike,
If your Alpha 91b does not trip out at 1500 watts on 75 meters SSB using other transceivers, then it looks as if your K3 may be either putting out a spike or the power output is not stable. You might want to go through the following K3 calibration procedures:

1) Synthesizer Calibration
2) Filter Setup (all five precedures listed for each filter installed).
3) Reference Oscillator Calibration
4) TX Gain Calibration on all bands

Hope this helps. Best 73, Roy Morris W4WFB
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html