Ultra Heavy BCB Dx'ing
 

bpnjensen wrote:
On Apr 16, 6:25 am, dave wrote:
Bob Dobbs wrote:
Geoffrey S. Mendelson wrote:
~~~
don't buy a SW, especially ham, receiver and expect it to perform
well on the AM BCB.
Why not?
I didn't initially buy any of my HAM rigs for use on AMBCB,
however a couple have turned out to perform very nicely there.
They're very stable (TCXO), have adjustable IF bandwidth and shift,
one of them has a convenient band scan to spot stations,
another actually has a spectrum scope to look at the band.
And even though that band is always full at night
it helps to see what's out there during the day.
The very best ram radio receivers have no coverage outside the ham
bands, where they are bandpass filtered.- Hide quoted text -

- Show quoted text -

Does that mean your Elecraft?

The Elecraft offers a general coverage option which includes switched
filters for the bands between the ham bands. I was thinking more of the
upscale classic Ten Tec.

Ultra Heavy BCB Dx'ing
 

Bob Dobbs wrote:
gnals from relatively local stations.

I sometimes get a long period QSB during the day,
noticeable with KFI-HD 640 from about 120 miles away up in LA,
such that it loses HD sync-lock for a while,
but for the most part, it's quite subtle, or imperceptible.
Nighttime is a whole nother situation!


The skywave gets 180 degrees out of phase with the groundwave sometimes.
They can cancel each other out. Usually though, the reflection is
asymmetric and only partial cancellation happens. This when you where
the flanger effect and the digital sidebands. KFI does it up here too.

Ultra Heavy BCB Dx'ing
 

Bob Dobbs wrote:
dave wrote:
Bob Dobbs wrote:
Geoffrey S. Mendelson wrote:

~~~

don't buy a SW, especially ham, receiver and expect it to perform
well on the AM BCB.
Why not?
I didn't initially buy any of my HAM rigs for use on AMBCB,
however a couple have turned out to perform very nicely there.
They're very stable (TCXO), have adjustable IF bandwidth and shift,
one of them has a convenient band scan to spot stations,
another actually has a spectrum scope to look at the band.
And even though that band is always full at night
it helps to see what's out there during the day.

The very best ram radio receivers have no coverage outside the ham
bands, where they are bandpass filtered.

I guess my gear all falls outside the "best ram radio receiver" category,
and are more accurately called general coverage HF radio receivers,
with the US amateur band plan imposed on the transmit function.
In one rig there 'were' three SMT diodes
each about the size of a grain of black pepper
that had to be excised. g


It's a matter of being able to use a low IF, and therefore a roofing filter.

Ultra Heavy BCB Dx'ing
 

Bob Dobbs wrote:
dave wrote:
Bob Dobbs wrote:
gnals from relatively local stations.
I sometimes get a long period QSB during the day,
noticeable with KFI-HD 640 from about 120 miles away up in LA,
such that it loses HD sync-lock for a while,
but for the most part, it's quite subtle, or imperceptible.
Nighttime is a whole nother situation!

The skywave gets 180 degrees out of phase with the groundwave sometimes.
They can cancel each other out. Usually though, the reflection is
asymmetric and only partial cancellation happens. This when you where
the flanger effect and the digital sidebands. KFI does it up here too.

Didn't you describe a sort of whumping thumping sound
when KFI had their IBOC on, what causes that?
BTW: Never heard anything like that here however.

You need bass capability. There is a wubba wubba wubba.

Ultra Heavy BCB Dx'ing
 

On Fri, 16 Apr 2010 11:33:05 -0700, dave wrote:

bpnjensen wrote:
On Apr 16, 6:25 am, dave wrote:
Bob Dobbs wrote:
Geoffrey S. Mendelson wrote:
~~~
don't buy a SW, especially ham, receiver and expect it to perform
well on the AM BCB.
Why not?
I didn't initially buy any of my HAM rigs for use on AMBCB,
however a couple have turned out to perform very nicely there.
They're very stable (TCXO), have adjustable IF bandwidth and shift,
one of them has a convenient band scan to spot stations,
another actually has a spectrum scope to look at the band.
And even though that band is always full at night
it helps to see what's out there during the day.
The very best ram radio receivers have no coverage outside the ham
bands, where they are bandpass filtered.- Hide quoted text -

- Show quoted text -

Does that mean your Elecraft?

The Elecraft offers a general coverage option which includes switched
filters for the bands between the ham bands. I was thinking more of the
upscale classic Ten Tec.

What kind of BCB performance do you get on the K3?

Ultra Heavy BCB Dx'ing
 

Ultra Heavy BCB Dx'ing
 

Bob Dobbs wrote:
dave wrote:

Didn't you describe a sort of whumping thumping sound
when KFI had their IBOC on, what causes that?
BTW: Never heard anything like that here however.

You need bass capability. There is a wubba wubba wubba.

My HD box does have fair bass.
Maybe some multipath weirdness to your direction,
but I'm too far away in the other direction to experience it down here.


I hear it on every AM HD station when I listen to one sideband at a
time. Try KFBK 1530 tonight.

Ultra Heavy BCB Dx'ing
 

Bob Dobbs wrote:
dave wrote:

It's a matter of being able to use a low IF, and therefore a roofing filter.

A couple are triple conversion but only one has a 'roofing' filter.


The Elecraft has a first IF of 8.2 MHz. Then there's a xtal filter,
then the second IF of 15 KHz, which directly feeds the DSP demodulator.

Ultra Heavy BCB Dx'ing
 

On Fri, 16 Apr 2010 07:52:05 -0700 (PDT), bpnjensen
wrote:

On Apr 16, 6:34*am, dave wrote:
Geoffrey S. Mendelson wrote:
Bob Dobbs wrote:
9kc wide in AM mode is the best I can manage.

For shortwave, 2.4 which is what most ham rigs deliver is too narrow,
4 is about the best and 6 is better if there is no adjacent channel
interference.

BCB AM works best with wider filters, depending upon what's close by.

I don't know how it is elsewhere, here I get a half a dozen or so BCB AM
stations, lots of SWBC (mostly on 40m) and the FM band has a station every
100kHz.

None of my HAM rigs have a sync-det, but a couple are stable enough on SSB to
accomplish the same effect. Only one of the SW portables has sync-det and it's
nice because it does DSB too on occasion when that mode is advantageous.

Is it really needed for broadcast band AM? I see very little if any fading
and can not remember it every being a problem.

I still don't know of any amateur rigs that tailor their coverage to BCB
although there are plenty that include it in the 30kc~30Mc spread.

I don't think there are any. It's not something the customers want and
ones sold in the US generally have extra front end antenuation for the
BCB.

They have to have the US amateur band plan restrictions superimposed
for type acceptance to be sold as an amateur HF transmitting device
in the USA (Usually deactivated by diode removal).

That's only for transmit. Very few countries restrict reception of anything
below 30mHz.

I use long outdoor omni antennas on all my amateur radios for AMBCB.
But I do have a tunable loop that works great with the SW portable.

I use a 20 meter long random wire with my r5000 and a 6 meter (high not
band) aluminum pole on my ham rigs. My SPR-4 works fine with the pole.

Geoff.

Really? *Selective fading is a major issue here on mediumwave.- Hide quoted text -

- Show quoted text -

Yes, here too - ever since I can remember - not only for the nighttime
DX, but also for day signals from relatively local stations.

Once they let a few more of those IBOC HD stations operate at night,
the whole AM band will be wiped out. 31 kHz for bandwidth is
ridiculous.

Jim

Ultra Heavy BCB Dx'ing
 

On Apr 17, 9:03*am, dave wrote:
Bob Dobbs wrote:
dave wrote:

Didn't you describe a sort of whumping thumping sound
when KFI had their IBOC on, what causes that?
BTW: Never heard anything like that here however.

You need bass capability. *There is a wubba wubba wubba.

My HD box does have fair bass.
Maybe some multipath weirdness to your direction,
but I'm too far away in the other direction to experience it down here.

I hear it on every AM HD station when I listen to one sideband at a
time. *Try KFBK 1530 tonight.

I tuned into 1530 at 0718 and what do I hear? Nothing but The Prophet
himself - Brother Ralph Stair. Good entertainment too listen to but
how in the world has that fella avoided serious joint time is beyond
me? Only in America. I think I will tune somewhere else now. ;-)