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K3 for Broadcast Band DX

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Carl Jón Denbow

K3 for Broadcast Band DX

I sometimes like to do a little Broadcast Band DX, takes me back to my
high schools days with my GE transistor radio under the pillow. I think
some of you know the story. ;-) At any rate, I have the general
coverage module installed in the main receiver, but I have found the
sensitivity of it in the broadcast band to be horrible. I can hook up
my Palstar R40 and get a 40 over signal from a station, but with the K3
hooked up to the same antenna that station is an S4 -- just barely
over the noise level. This is a station 100 miles way that I could
receive on that old GE transistor radio at what would have at least been
an S9 signal. Therefore, at this juncture, the K3 is totally not up to
the job when it comes to broadcast band DX hunting. What's up here?
--
=================================================
Carl Jón Denbow, N8VZ
17 Coventry Lane
Athens, Ohio 45701-3718

[hidden email]
www.n8vz.com
EM89wh

IRLP 4533 Echolink 116070

PSK and JT65 Forever!
=================================================

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Joe Subich, W4TV-4

Re: K3 for Broadcast Band DX

> Therefore, at this juncture, the K3 is totally not up to the job when
> it comes to broadcast band DX hunting. What's up here?

As documented here literally dozens of times, the TR switch contains a
high-pass filter with a 1600 KHz cutoff to protect the PIN diodes and
keep them from generating interference due to strong broadcast band
signals. If you want to receive the broadcast (and MW bands) with full
sensitivity, 1) install the BPF3 receive filter *and* 2) use a separate
receive antenna connected to either the RX ANT IN jack or the XVTR IN
jack.

73,

... Joe, W4TV

On 2015-06-08 3:04 PM, Carl Jón Denbow wrote:

> I sometimes like to do a little Broadcast Band DX, takes me back to my
> high schools days with my GE transistor radio under the pillow. I think
> some of you know the story. ;-) At any rate, I have the general
> coverage module installed in the main receiver, but I have found the
> sensitivity of it in the broadcast band to be horrible. I can hook up
> my Palstar R40 and get a 40 over signal from a station, but with the K3
> hooked up to the same antenna that station is an S4 -- just barely
> over the noise level. This is a station 100 miles way that I could
> receive on that old GE transistor radio at what would have at least been
> an S9 signal. Therefore, at this juncture, the K3 is totally not up to
> the job when it comes to broadcast band DX hunting. What's up here?

Carl Jón Denbow

Re: K3 for Broadcast Band DX

Thanks, Joe. I knew there was some logical explanation. I did do a
search of previous posts before I asked my question and I didn't find
any post that was the direct answer I needed.

73,

Carl
N8VZ

> Joe Subich, W4TV <mailto:[hidden email]>
> Monday, June 8, 2015 3:25 PM
>
>> Therefore, at this juncture, the K3 is totally not up to the job when
>> it comes to broadcast band DX hunting. What's up here?
>
> As documented here literally dozens of times, the TR switch contains a
> high-pass filter with a 1600 KHz cutoff to protect the PIN diodes and
> keep them from generating interference due to strong broadcast band
> signals. If you want to receive the broadcast (and MW bands) with full
> sensitivity, 1) install the BPF3 receive filter *and* 2) use a separate
> receive antenna connected to either the RX ANT IN jack or the XVTR IN
> jack.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 2015-06-08 3:04 PM, Carl Jón Denbow wrote:
>> I sometimes like to do a little Broadcast Band DX, takes me back to my
>> high schools days with my GE transistor radio under the pillow. I think
>> some of you know the story. ;-) At any rate, I have the general
>> coverage module installed in the main receiver, but I have found the
>> sensitivity of it in the broadcast band to be horrible. I can hook up
>> my Palstar R40 and get a 40 over signal from a station, but with the K3
>> hooked up to the same antenna that station is an S4 -- just barely
>> over the noise level. This is a station 100 miles way that I could
>> receive on that old GE transistor radio at what would have at least been
>> an S9 signal. Therefore, at this juncture, the K3 is totally not up to
>> the job when it comes to broadcast band DX hunting. What's up here?
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
> Carl Jón Denbow <mailto:[hidden email]>
> Monday, June 8, 2015 3:04 PM
> I sometimes like to do a little Broadcast Band DX, takes me back to my
> high schools days with my GE transistor radio under the pillow. I
> think some of you know the story. ;-) At any rate, I have the general
> coverage module installed in the main receiver, but I have found the
> sensitivity of it in the broadcast band to be horrible. I can hook up
> my Palstar R40 and get a 40 over signal from a station, but with the
> K3 hooked up to the same antenna that station is an S4 -- just
> barely over the noise level. This is a station 100 miles way that I
> could receive on that old GE transistor radio at what would have at
> least been an S9 signal. Therefore, at this juncture, the K3 is
> totally not up to the job when it comes to broadcast band DX hunting.
> What's up here?

--
=================================================
Carl Jón Denbow, N8VZ
17 Coventry Lane
Athens, Ohio 45701-3718

[hidden email]
www.n8vz.com
EM89wh

IRLP 4533 Echolink 116070

PSK and JT65 Forever!
=================================================

______________________________________________________________
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
Message delivered to [hidden email]

Re: K3 for Broadcast Band DX

In reply to this post by Joe Subich, W4TV-4

Along this subject of BPF3 - When I assembled my K3 with sub rx - I put the
BPF3 in the sub rx - on the assumption that it might degrade the out of
band main rx protection with some filter blow by if I put it in the main
rx path. Now I wish I had put in in the main rx so I could use the P3 out
of the ham bands- especially below 160)

Was this a false worry ? (I live in a hot bed within 3 to 4 miles of several
contesters / dxers with HUGE signals at my place - two of whom can put 50 to
100 mv of signal here on 160 - easy to see both on a scope on antenna)

I am going to buy the new KXV3B and will have to take the sub rx out to
install and that would be a good time to move that filter if its not an
issue.

Hank K7HP

-----Original Message-----
From: Joe Subich, W4TV
Sent: Monday, June 08, 2015 12:25 PM
To: [hidden email]
Subject: Re: [Elecraft] K3 for Broadcast Band DX

> Therefore, at this juncture, the K3 is totally not up to the job when
> it comes to broadcast band DX hunting. What's up here?

As documented here literally dozens of times, the TR switch contains a
high-pass filter with a 1600 KHz cutoff to protect the PIN diodes and
keep them from generating interference due to strong broadcast band
signals. If you want to receive the broadcast (and MW bands) with full
sensitivity, 1) install the BPF3 receive filter *and* 2) use a separate
receive antenna connected to either the RX ANT IN jack or the XVTR IN
jack.

73,

... Joe, W4TV

On 2015-06-08 3:04 PM, Carl Jón Denbow wrote:

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

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Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

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

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wayne burdick

Re: K3 for Broadcast Band DX

Administrator

Hank,

When you're in or close to a ham band, the broader KBPF3 filters are not used; the K3's narrow ham-band filters are used. This applies to both the main and sub receivers. The KBPF3's filters are only used when you're far enough outside a ham band to result in noticeable loss of sensitivity.

So in answer to your question: No, you don't need to worry. When the KBPF3 is not in use (main or sub), it is completely out of the circuit, having no impact on filtering.

By the way: the K3's narrow ham-band filters are one of its biggest assets. Most transceivers these days, even superhet designs, use very broad filters intended to cover multiple bands. The K3 (and K3S), in contrast, use filters that just cover the ham band of interest, providing high degree of rejection of out of band signals. This has a secondary benefit in reduction of "IP2" (intermodulation products resulting from the mixing of strong signals prior to the band pass filter array).

73,
Wayne
N6KR

On Jun 8, 2015, at 2:14 PM, "Hank P" <[hidden email]> wrote:

> Along this subject of BPF3 - When I assembled my K3 with sub rx - I put the
> BPF3 in the sub rx - on the assumption that it might degrade the out of
> band main rx protection with some filter blow by if I put it in the main
> rx path. Now I wish I had put in in the main rx so I could use the P3 out
> of the ham bands- especially below 160)
>
> Was this a false worry ? (I live in a hot bed within 3 to 4 miles of several
> contesters / dxers with HUGE signals at my place - two of whom can put 50 to
> 100 mv of signal here on 160 - easy to see both on a scope on antenna)
>
> I am going to buy the new KXV3B and will have to take the sub rx out to
> install and that would be a good time to move that filter if its not an
> issue.
>
> Hank K7HP
>
>
>
> -----Original Message----- From: Joe Subich, W4TV
> Sent: Monday, June 08, 2015 12:25 PM
> To: [hidden email]
> Subject: Re: [Elecraft] K3 for Broadcast Band DX
>
>
>> Therefore, at this juncture, the K3 is totally not up to the job when
>> it comes to broadcast band DX hunting. What's up here?
>
> As documented here literally dozens of times, the TR switch contains a
> high-pass filter with a 1600 KHz cutoff to protect the PIN diodes and
> keep them from generating interference due to strong broadcast band
> signals. If you want to receive the broadcast (and MW bands) with full
> sensitivity, 1) install the BPF3 receive filter *and* 2) use a separate
> receive antenna connected to either the RX ANT IN jack or the XVTR IN
> jack.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 2015-06-08 3:04 PM, Carl Jón Denbow wrote:
>> I sometimes like to do a little Broadcast Band DX, takes me back to my
>> high schools days with my GE transistor radio under the pillow. I think
>> some of you know the story. ;-) At any rate, I have the general
>> coverage module installed in the main receiver, but I have found the
>> sensitivity of it in the broadcast band to be horrible. I can hook up
>> my Palstar R40 and get a 40 over signal from a station, but with the K3
>> hooked up to the same antenna that station is an S4 -- just barely
>> over the noise level. This is a station 100 miles way that I could
>> receive on that old GE transistor radio at what would have at least been
>> an S9 signal. Therefore, at this juncture, the K3 is totally not up to
>> the job when it comes to broadcast band DX hunting. What's up here?
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
> ______________________________________________________________
> 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
> Message delivered to [hidden email]

KENT TRIMBLE

Re: K3 for Broadcast Band DX

In reply to this post by Carl Jón Denbow

For me it was a brand-new Zenith Royal 500 "Long Distance" 7-transistor radio in burgundy with vernier tuning, leather carrying case, and earphone.

Around midnight in the summer of 1958 I lay, a 13-year old boy in Illinois, listening to KDKA in Pittsburgh broadcast live updates on a commercial piston aircraft circling the airport with landing problems. High drama for over an hour with anxiety clearly evident in the reporter's voice. I eventually fell asleep (radio on, earphone in place) and learned the next day the plane had landed safely. Rare excitement on the airwaves at the time and just one of several broadcast-band adventures which led in due course
to a Novice license soon thereafter.

Still have the Royal 500, too.

73,

Kent K9ZTV

> On Jun 8, 2015, at 2:04 PM, Carl Jón Denbow <[hidden email]> wrote:
>
> I sometimes like to do a little Broadcast Band DX, takes me back to my high schools days with my GE transistor radio under the pillow. I think some of you know the story. ;-)
______________________________________________________________
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
Message delivered to [hidden email]

OE5CSP-Chris

Re: K3 for Broadcast Band DX

In reply to this post by Joe Subich, W4TV-4

I´d like to know if the K3 can compete with a good world receiver on the BC bands. I´m asking this before placing my order for the general coverage modul.
What about the audio and medium wave?
73,Chris-OE5CSP