[Elecraft] Fwd: Re: T/R switching problem

Wed Mar 26 14:30:13 EDT 2014

Phil:

I would keep a close eye on this.  I had a bad issue with attenuation and
rectification using the K3-KPA500 ..only existing when the amp was on and in
operating mode.  It turned out to be a bad capacitor in one of the low pass
filters.  Sent it back to Elecraft ..and fixed quickly.  I'd give them a
call.

73
Steve KL7SB

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Toby Pennington
Sent: Wednesday, March 26, 2014 9:01 AM
To: Elecraft at mailman.qth.net
Subject: [Elecraft] Fwd: Re: T/R switching problem

The only time I have experienced some amount of attenuation on receive is
when I was using some other amplifier besides the KPA 500.

I found I had to totally disconnect all my cabling between the amplifier 
and the rig.   Since I am using the K line completely, trying to use an 
external amp other than the KPA 500  can be done without disconnecting all
the cabling,  but on receive you will experience attenuation of the receive
signals.  To have full receive using another brand of amp,  you will have to
remove the data transfer cabling between the rig and amp. 
    I hope I have this right,  as it has been some time since I experimented
with using an amp with more output than the KPA 500.

Toby  K4NH

-------- Original Message --------
Subject: 	Re: [Elecraft] T/R switching problem
Date: 	Wed, 26 Mar 2014 06:53:18 -0700
From: 	Phil Hystad <phystad at mac.com>
To: 	Mike K2MK <k2mk at comcast.net>
CC: 	elecraft at mailman.qth.net

I have a similar (close but not identical to symptoms below) problem with
K3 receive attenuation.  I do not have a SteppIR and this same problem
occurred on more than one antenna (80-meter dipole, Traffie Hex Beam).

My symptoms were that when I turned on the radio in the morning, the band
per the display on the P3 was flat, virtually no "visible" signals.  No
matter as I was doing my morning reading with my coffee.

Later, I went to the radio and there should have been some good activity on
20, 17, 15, 12, and 10.  I did have signals but no where near as much as I
think there should have been.  I thought maybe the KAT500 was out of tune so
I fooled with that, Xmitted tune and so on and no real change.

I checked everything I could think of such as change in PRE setting (I was
on PRE), Attenuation (no, was not), and so on.

Finally, I tried the old computer programming trick, turn it off and turn it
on again.

When the K3 came back up the bands were crowded with signals.  So, there was
some significant attenuation going on but turning off (front panel switch
only) the K3 and turning it back on fixed everything.

Ideas, comments??  Oh, this has happened only that one time so far.

73, phil, K7PEH

On Mar 26, 2014, at 4:14 AM, Mike K2MK <k2mk at comcast.net> wrote:

> Hi Jan,
>
> What is your antenna. There has been an ongoing thread on the SteppIR 
> site regarding this identical problem with many types of transceivers, 
> not just the K3. If you have a SteppIR antenna (any model) you should 
> take a look at their Yahoo site.
>
> 73,
> Mike K2MK
>
>
> Jan Ditzian wrote
>> I am having a problem with T/R switching in my K3.  The symptom is 
>> that, after I transmit, the receive signals are sometimes very
attenuated.
>> This problem has gotten worse.  At first, simply a quick tap on the 
>> PTT switch fixed everything, but now, at least on phone, I must make 
>> a brief additional transmission to get the receive to return.  Today, 
>> the problem got worse, and sometimes I have to really fuss with 
>> things to get receive back.  Here are some questions:
>>
>> 1. Is there a T/R relay in the K3, and does this sound like it is
>>    sticking, at least to the extent that it does not make good contact
>>    on receive?
>> 2. Has anyone had the similar problem, and what was the solution?
>> 3. If it is a relay, can it be replaced easily, or is this a return to
>>    Elecraft situation?
>> 4. If it is simply a relay replacement, where is the relay located?
>>
>> Thank you,
>>
>> Jan, KX2A
>
>
>
>
>
> --
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