K3 and transverters

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K3 and transverters

Gary Gregory
*Has anyone got a K3 with the 2M and 70cm transverters got any comments
plus or minus as to performance.

I don't have them myself but a VK is about to order his K3 and will be
adding these transverters.

His interest is HF, 2 and 70cm and not 6M.

I thought I would ask here as I don't know what to tell him due to lack of
experience in the higher bands.

Off list or On is OK as long as it doesn't flood the reflector with
QRM.....:-)

73
*
--
*Gary*
*Start the day off slow, then taper off.........*
K3 #679
KPA500FT #18
KAT500FT 007
P3 #1629
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Re: K3 and transverters

John Ragle
I have a K3 with the XV transverters for 2 and 3/4 meters. (NOTE: these
are the outboard transverters!) They drive 2 and 3/4 meter TE Systems
brick amps to about 300 watts and 75 W respectively.

Two comments:

1. The inboard transverter for 2 meters could never be made to
function...the unit oscillated with great abandon, despite the best
advices of Elecraft. If you look back through the archives, you will
find several reports, including one from VK, reportiong this behavior.
The K3 works flawlessly with the external units, which I built from kits.

2. For anything but local use, the most important part of the chain is
the antenna; its location, height, gain, etc. In particular, at 3/4
meters the bound -water dielectric loss from water in vegetation is very
significant, and the antenna must be well above (i.e. must "look" over)
nearby trees, Koala Bears, etc. I use a 10 element beam on 2 and an 11
element beam on 3/4 meters, and these are barely adequate for DX use
from my location. A good antenna installation (high-gain array, proper
feed lines) will overcome any slight deficiencies in the transverter
front end...if one can hear antenna noise, one is fine.

John Ragle -- W1ZI

==========

On 9/15/2012 10:05 AM, Gary Gregory wrote:

> *Has anyone got a K3 with the 2M and 70cm transverters got any comments
> plus or minus as to performance.
>
> I don't have them myself but a VK is about to order his K3 and will be
> adding these transverters.
>
> His interest is HF, 2 and 70cm and not 6M.
>
> I thought I would ask here as I don't know what to tell him due to lack of
> experience in the higher bands.
>
> Off list or On is OK as long as it doesn't flood the reflector with
> QRM.....:-)
>
> 73
> *

--
Sent from my lovely old Dell XPS 420

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Re: K3 and transverters

N0AZZ
In reply to this post by Gary Gregory
Gary

The K3 with the internal 2m module works excellent and it doesn't have to
hang off the back of the transceiver. As for the 70cm the only choice for it
is the transverter as far 6m if is already in the K3 to begin with.

I use a smaller amp to drive my large 2m amp and it works out quite well
that way. I do have a friend who has both the Elecraft transverters for
2/6/432m for his K2 and like them.

73,
Fred/N0AZZ

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Gary Gregory
Sent: Saturday, September 15, 2012 5:06 AM
To: Elecraft
Subject: [Elecraft] K3 and transverters

*Has anyone got a K3 with the 2M and 70cm transverters got any comments plus
or minus as to performance.

I don't have them myself but a VK is about to order his K3 and will be
adding these transverters.

His interest is HF, 2 and 70cm and not 6M.

I thought I would ask here as I don't know what to tell him due to lack of
experience in the higher bands.

Off list or On is OK as long as it doesn't flood the reflector with
QRM.....:-)

73
*
--
*Gary*
*Start the day off slow, then taper off.........*
K3 #679
KPA500FT #18
KAT500FT 007
P3 #1629
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Re: K3 and transverters

David Pratt
In reply to this post by Gary Gregory
I would say go for it, Gary. The Elecraft transverters all have a high
gain, low noise front end using the ATF-34143 Pseudomorphic High
Electron Mobility Transistor (HEMT). I presume your VK friend will be
using the internal (K144XV) 2M xverter and the external (XV432) 70cm
xverter. If he is going to get the K144XV I would recommend he also gets
the K144RFLK to ensure best stability when using CW/SSB/Data.

I do not have the 70cm XV432, but have the internal 2m xverter and an
external XV70 4m and they work fine.

73 de David G4DMP

In a recent message, Gary Gregory <[hidden email]> writes

>*Has anyone got a K3 with the 2M and 70cm transverters got any comments
>plus or minus as to performance.
>
>I don't have them myself but a VK is about to order his K3 and will be
>adding these transverters.
>
>His interest is HF, 2 and 70cm and not 6M.
>
>I thought I would ask here as I don't know what to tell him due to lack of
>experience in the higher bands.
>
>Off list or On is OK as long as it doesn't flood the reflector with
>QRM.....:-)

There's no QRM on the reflector, just Phase Noise!

--
 + - - - - - - - - - - - - - - - - +
 | David M Pratt, Kippax, Leeds.   |
 | Website: http://www.g4dmp.co.uk |
 + - - - - - - - - - - - - - - - - +

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Re: K3 and transverters

David Pratt
In reply to this post by John Ragle
In a recent message, John Ragle <[hidden email]> writes
>1. The inboard transverter for 2 meters could never be made to
>function...the unit oscillated with great abandon, despite the best
>advices of Elecraft.

There was instability on the early K144XV units, but there is a very
simple mod that cures it. It is a simple matter of removing a screw. It
is the central screw on the top cover. I replace the existing metal
pillar and screw with nylon ones and the instability disappeared like
magic. I thought there was a mod sheet about that. Wayne/Eric - is
there?

73 de David G4DMP

--
 + - - - - - - - - - - - - - - - - +
 | David M Pratt, Kippax, Leeds.   |
 | Website: http://www.g4dmp.co.uk |
 + - - - - - - - - - - - - - - - - +

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Re: K3 and transverters

Sebastian, W4AS
In reply to this post by Gary Gregory
With a K3 I use the XV144, XV222 and XV432 external transverters.

At first I was very disappointed with their frequency drift.  It was difficult to stay on frequency from a cold start, and it would continue to drift the more I transmitted.

Installing the $100 TCXOs helped but didn't really solve the issue.  To minimize frequency drift, the manual suggests to always have the local oscillator powered, easily accomplished by changing a jumper inside; note that requires 12 volts to always be present.

I checked the voltage on the 25 amp power supply I was using (a bit overkill on the current, yet it was what I had that wasn't being used) and made sure that it didn't deviate over time or while transmitting.

Frequency stability is very important to me as I often run meteor scatter contacts which are quite dependent on accurate frequency control, and demands a key down time of 30 seconds on and 30 seconds off.

I thought that perhaps by placing one transverter on top of each other as I had done, wasn't helping the cooling, so I made a little cabinet which offers approximately 3 inches of separation on all sides from the trio.  Again, that didn't help very much.

Frankly I was ready to go back to a TS-2000 for VHF/UHF as I hadn't been able to solve the drift issue, and it was embarrassing to talk to the locals on 2 meter SSB when I was drifting for the first few minutes.

Finally, the problem was solved rather easily.  After reading through similar stories from other hams, I found an old cooling fan for a 486 CPU processor which has almost the same dimensions as the small cooling holes on top of each transverter.  I applied double-sided tape to each corner of the fan, and placed it on top of the cooling holes.  As long as the little fan is on, the transverters will drift only a small amount, which is acceptable for the modes I use.

Note that my XV144 is the one I use the most often, and is setup to output only about 4 watts, which is enough to generate 50 watts from one amp (Mirage B108 capable of 80 watts), which is enough to fully drive my 300 watt amp (Mirage B5030G).  These amps and the XV144 are keyed using an external sequencer.  I'm not sure if the little fan would help if you were to use the full 25 watts output of the transverters.  I should also note that the K3 is driving them with very little power (I forget exactly how many milliwatts).

Don't use a large computer power supply fan, as the fan motor will be similar in size to the cooling holes, which means you would actually be covering them up and making the problem worse.

Finally, I haven't come up with a neat way of daisy chaining them.  Typically you would use BNC T connectors, but having three transverters close to each other, with six coaxial cables connected with six BNC T connectors creates quite a mess; in addition to the control cables, but that's just a minor issue.

73 de Sebastian, W4AS



On Sep 15, 2012, at 6:05 AM, Gary Gregory <[hidden email]> wrote:

> *Has anyone got a K3 with the 2M and 70cm transverters got any comments
> plus or minus as to performance.
>
> I don't have them myself but a VK is about to order his K3 and will be
> adding these transverters.
>
> His interest is HF, 2 and 70cm and not 6M.
>
> I thought I would ask here as I don't know what to tell him due to lack of
> experience in the higher bands.
>
> Off list or On is OK as long as it doesn't flood the reflector with
> QRM.....:-)
>
> 73
> *
> --
> *Gary*

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Re: K3 and transverters

K7MDL
This post was updated on .
For daisy chaining I use BNC to SMA adapters with SMA Tee connectors mounted.  Then I made up custom cables with quality coax (RG316) and SMA connectors cut to the perfect sizes to stack the transverters.  I have also used 2 pieces of aluminum angle stock as mounting ears to mount my XV stack into a box "rack".  Using RG316 everywhere and custom lengths, it comes out very tidy and well sheilded.   I leave my LOs on all the time, no fan, use the xtal ovens.  The XV144 stability was good enough for digital modes when I had that setup.

I use a 12VDC Sp4T SMA coax switch controlled by a slightly modified KRC2 to route my K3/K144XV 2M RF/IF and PTT to antenna or the 902/1296 transverters.  I have an extensive article written up with pictures and schematics on request.   My website no longer exists.

Edit: I should add the articles were written for the K2 as the driver.  The K3 is nearly the same connection-wise, I mostly swapped out the K2+XV144 for the K3+K144XV.  I had  to make a minor change to one of my KRC2 mods due to different voltages used which resulted in the aux bus locking up - hence the updated mod.

- Mike, K7MDL
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Re: K3 and transverters

John Ragle
In reply to this post by Sebastian, W4AS



On 9/15/2012 6:05 PM, Sebastian, W4AS wrote (regarding drift problems
with XV144 and XV432 transverters):
> <snip> To minimize frequency drift, the manual suggests to always have the local oscillator powered, easily accomplished by changing a jumper inside; note that requires 12 volts to always be present. <snip>

Since the local oscillator oven draws only minimal current, and since
the units draw very little total current in receive mode, it seems
logical to do as the manuals suggest and leave the units powered during
periods of potential use. Under these circumstances I have had no
problem with drift. I should mention that my XV144 is stacked on my
XV432 with 1" aluminum bar stock used for spacing, and there is no
cooling fan.

John Ragle -- W1ZI
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Re: K3 and transverters

Vic Goncharsky
In reply to this post by John Ragle
What I am personally looking for is information about on the air performance of 144 and 432 Elecraft transverters in strong signal environments like VHF/UHF contests in dense areas with multi-kilowatt  folks occupying mountain tops all around.

I planned to make K144XV test during the last IARU R1 VHF championship but due to the lack of upgraded KXV3A board this did not happen (my fault). On the other hand Kuhne "TR 144 H+40" and Elecraft K3 pair allowed to "forget" about front-end overload. 
http://www.youtube.com/watch?v=pUCECQmgrj0&feature=plcp
http://www.youtube.com/watch?v=0JL9GF1rBVo&feature=relmfu
VHF contesters opinions are welcomed.

73 Vic US5WE/K1WE (UW5W in VHF contests) KN29AU
UARL VHF committee
Chairman, UARL Lvov Branch "LKK"
Moderator, UARL VHF portal http://www.vhfdx.at.ua
DXCC card checker in Ukraine


________________________________
 From: Ron D'Eau Claire <[hidden email]>
To: [hidden email]
Sent: Saturday, September 15, 2012 11:02 PM
Subject: Re: [Elecraft] K3 and transverters
 
 ... My K144XV is perfectly well behaved... 

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Re: K3 and transverters

Jim Brown-10
On 9/15/2012 10:43 PM, Vic Goncharsky wrote:
> What I am personally looking for is information about on the air performance of 144 and 432 Elecraft transverters in strong signal environments like VHF/UHF contests in dense areas with multi-kilowatt  folks occupying mountain tops all around.

I recall such a review in QST something like 4-5 years ago. Obviously it
applies to the outboard unit, and I think I recall it being the 2M
version.  Check the ARRL product review archives. Members can download
the pdf.  I do remember that it was tested in a contesting environment
(east coast, maybe New England or the mountains around DC) with a lot of
strong signals, and that it was a very positive review.

73, Jim K9YC
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Re: K3 and transverters

K7MDL
I used mine at home and more often on mountain tops during VHF+ contests as a rover.  I am often in line of sight to other high power rovers and the KW stations in the valleys below.  I used a K2 with my transverters.  After a number of previous rover setups that did not do well, I found this combo worked well.  I had no more adjacent bleed issues, and stability was quite acceptable.  I have since swapped the K2 for the K3 "just because" :-) .

I have not had the K3 combo out on a mountain top yet.  I have done extensive A/B swapping at the home station between the XV144 and K144XV and show no discernable difference in performance except some noise/spur pickup and lower output power in the K144XV (no surprise).  That is offset by having the 4Mhz band coverage making FM possible.  I like that since I an pickup Simplex QSOs and do some occasional repeater or satellite work and use the same antennas, no extra switching or rotators required.

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Re: K3 and transverters

Don Wilhelm-4
In reply to this post by Jim Brown-10
Jim,

"mountains around DC" ???
I used to live in Barnsville, MD overlooking Sugarloaf Mountain, and
that is about as close to "mountains around DC"  as it gets.  I cannot
recall the height of Sugarloaf Mountain, but it was not that great, and
it was private property when I was there in the 1980s - but the owners
provided a path to the summit for visitors.

It was often referred to as a "bump out of place".  One must go quite a
ways Northwestward from DC to encounter mountains.   Western Maryland
yes, Southern Pennsylvania, yes, but much of Maryland is the eastern
coastal. plains was flat and without "bumps"- yes those Eastern coastal
plains do turn quickly into mountains, so your choice of position is a
big factor in your assessment of vertical altitude.

If one wants mountains when in Maryland, it is advised to head for
Western Virginia and the Shenandoah Mountain range.  Southwest of
Maryland is the great Shenandoah National Park where My family
vacationed for many years.  My children grew up on the instructions from
the park rangers at Big Meadows.

73,
Don W3FPR

  9/16/2012 2:06 AM, Jim Brown wrote:

> On 9/15/2012 10:43 PM, Vic Goncharsky wrote:
>> What I am personally looking for is information about on the air performance of 144 and 432 Elecraft transverters in strong signal environments like VHF/UHF contests in dense areas with multi-kilowatt  folks occupying mountain tops all around.
> I recall such a review in QST something like 4-5 years ago. Obviously it
> applies to the outboard unit, and I think I recall it being the 2M
> version.  Check the ARRL product review archives. Members can download
> the pdf.  I do remember that it was tested in a contesting environment
> (east coast, maybe New England or the mountains around DC) with a lot of
> strong signals, and that it was a very positive review.
>
> 73, Jim K9YC
> ______________________________________________________________
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>

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Re: K3 and transverters

Geoffrey Downs-3
In reply to this post by John Ragle
It's possible that I was among the first, if not the first, to report the
K144XV self-oscillation problem in March 2010 not long after it started
shipping. It took six months to solve, including 3 replacements units, a
replacement KXV3A and a lot of emails, tests and effort on both sides of the
Atlantic. David G4DMP whose K144XV showed the same problem eventually
isolated it. As he has said in an earlier posting, the solution, discovered
in September 2010, was simple in the end. It is implemented in K144XVs
shipped since then and referred to in an Errata Sheet for the K144XV
Installation Manual dated September 30th 2010.  It applies to pages 15 and
16 of the Manual and involves the omission of one of the screws holding the
top cover. I believe the metal standoff beneath the hole may also be omitted
now but is still shown in the photograph on page 14 of the Manual, the date
of which precedes the solution. In the unlikely event of anyone out there
still having the problem, the above details may help.

As will be apparent the support from Elecraft was unstinting and the K144XV
may now be bought with full confidence. I would agree, however, that the
K144RFLK is essential, for CW and SSB operation operation at least. I have
never had problems with strong local signals but here the 2m band is so
rarely awash with them that it's not surprising.

73 to all

Geoff
G3UCK


-----Original Message-----
From: Ron D'Eau Claire
Sent: Sunday, September 16, 2012 12:02 AM

It's my understanding that the oscillation problem was solved long ago by
(IIRC) a change in the K144XV pc board ground scheme.

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Re: K3 and transverters

Jim Brown-10
In reply to this post by Don Wilhelm-4
On 9/16/2012 12:20 AM, Don Wilhelm wrote:
> "mountains around DC" ???

As a WV native, with family in the panhandles of MD and WV, I am
thinking of the mountains to the W and SW of DC.  When I was growing up
(in the 50s), metro DC was a lot smaller than it is now, consisting
mostly of close-in suburbs like Fairfax, Arlington, Bethesda, etc.  Now,
DC bedroom communities extend well into MD, PA, VA and WV, where there
are, indeed, mountains. Most contesters in that area are members of
either the Potomac Valley Radio Club or the Frankfort Radio Club, and
last I heard, many DO head for the mountains for VHF contests.  I
remember doing so when I was growing up in the Ohio Valley.

73, Jim K9YC
Official Hillbilly :)
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