Halligan's Hallicrafters International

    Halligan's Hallicrafters International
maintained by Scott Neader, KA9FOX





From: jcandela@prodigy.net
Date: Fri, 07 Dec 2001 18:11:53 -0500
Subject: Re: [AMRadio] Narrow Band FM
Message-Id: <AA-E37218ED8A098FEE0B062B3C82ACE0FD-ZZ@homebase1.prodigy.net>


http://www.amfone.net - Home of the AM Radio List.

To post or see items for sale or wanted, go to the new AM'ers Trading post below.
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     I want to jump in and relate an experience I had 
with NBFM. For over a year I had a weekly schedule 
with KD6OS on 7157.5 Khz. This was in the evenings on 
a Saturday night. We both ran high power (> 500 watts 
out), and FM with a modulation index around 0.5 

     We were squeezing our carrier between two foreign 
broadcast stations (7155, 7160). It was impossible to 
use AM under these conditions because the sidebands 
from the megawatt foreign broadcast stations left no 
clear frequency between them. Using "sliver band" NBFM 
under this situation worked well due to the 
concentration of my carrier power where the broadcast 
sidebands were weakest. The capture effect of FM made 
this happen. There were times when we had two way full 
quieting contacts.
   I used a SP-600 for a receiver, and ran the 455 Kc 
IF into an old KDK 2 meter rig for FM detection. I set 
the receiver bandwith to 3 Khz on the super pro. The 
KDK had a ~ 20 Khz bandwith which didn't seem to 
matter because the selectivity of the SP IF was 
already set at 3 Khz.
    For transmit I used a VF-1 with a added reactance 
modulator. What a mess. Had to regulate everything, 
including DC regulated at 5.5 volts on the filaments. 
The VF-1 excited a globe king 500 with a 2.5 Kv 
external RF amp P/S.
    One problem though with such low deviation, you 
have to crank the audio gain to get useable audio. 
When QSB sets in, and the signal fades, be prepared 
for the audio to blast out of the speaker. Most 
annoying. Some form of peak limiter on the receive 
audio would be beneficial.
Jim WD5JKO

PS Anybody hear from Ralph KD6OS?



--- Original Message ---
From: "Jay Bromley" <w5jay@alltel.net>
To: "John Coleman" <jec@pctechref.com>, "'Bob Bruhns'" 
<bbruhns@erols.com>, "AMRadio \(E-mail\)" 
<amradio@qth.net>
Subject: Re: [AMRadio] Narrow Band FM

>http://www.amfone.net - Home of the AM Radio List.
>
>To post or see items for sale or wanted, go to the 
new AM'ers Trading post below.
>http://www.amfone.net/cgi-bin/ikonboard/ikonboard.cgi
>
>John hi,
>Back in the mid 80s when all the talk about reducing 
AM power, PEP, etc, a
>lot of guys were threatening to use NBFM and did.  I 
played a little on 75m
>and 160m in the daytime.  It was fun talking to guys 
that were mobile near
>Tyler, TX.  They were amaze how well it worked in the 
daytime.  We tried to
>get guys to hang out on 75m NBFM instead of on 2m, 
but it never did become
>popular.  Always we would start out with a couple of 
guys and end up with a
>half a dozen or so in the round table.  I think one 
of the things that
>bugged the new guys checking in was the legality of 
the mode.  I know, I
>know, but the guys wouldn't and still don't check out 
things on their own.
>There are guys now on the bands now the say anything 
over 3 kHz on SSB is
>illegal, go figure.  John your AM signal has always 
sounded so good and
>strong, it would be waste to use NBFM instead of your 
AM rig.  Maybe less
>interference if you had neighbors nearby, well maybe 
not as noticeable??
>Have fun and ---
>
>73 de w5jay/jay..
>
>
>>
>> Thanks Bob:
>> I guess my suspicions are some what true.  NBFM 
might be a pleasant
>> experiment under ideal or local ground wave 
conditions but it is probably
>> not for every night operations on 75 mtrs.  Then 
again a rig with 2000
>watts
>> DC input to generate a carrier level of 1500 watts 
output, might with the
>> 3-4 DB increase help with the interference, but I 
guess not with the
>> distortion caused by selective fade.  BTW, I love 
your explanation with
>the
>> clock hand vectors.  Have you looked at my site
>> http://www.qsl.net/wa5bxo/amtech.html?  Don, K4KYV 
helped me with the
>> remembering.  With your permission I would like to 
post some or all of
>your
>> explanations to this site.  Also, if you see 
something that is not
>accurate
>> on the web page please let me know.  If you have a 
link to a page where
>some
>> of you explanations or already posted let me know 
and I will provide a
>link
>> to it.  If you would prefer to write your own HTML 
I would be glad to post
>> that as well.  After reading some of your writings 
I feel confidant in
>your
>> accuracy especially when you find the need to 
correct it yourself.
>>
>
>
>
>
>______________________________________________________
>
>To leave AMRadio , send mailto:majordomo@qth.net
>with the BODY of the message containing:
>
>unsubscribe amradio



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From: Brett Gazdzinski <brett.gazdzinski@wcom.com>
Date: Fri, 07 Dec 2001 14:53:30 -0500
Subject: RE: [AMRadio] Cylindrical 811A's needed
Message-id: <000701c17f58$dbed5be0$bdb220a6@wcomnet.com>


http://www.amfone.net - Home of the AM Radio List.

To post or see items for sale or wanted, go to the new AM'ers Trading post below.
http://www.amfone.net/cgi-bin/ikonboard/ikonboard.cgi

Jim,
I built the rig with the big kilowatt coils, so I can use
almost anything that will fit in.

I have a pair of 572b tubes, but heard they modulate poorly
as well...same as 811's, although 812's work real well.
Zero bias triodes cant modulate well because of the
tube bias/plate current curves.

Since the rf deck is done, I am limited to two tubes.

The power supply is set up for the 1500 to 1700 volt range,
and works with the modulators.

I COULD have tried all sorts of other tubes, but wanted
the voltage low, and common inexpensive tubes to use.
I HAVE some 812A's, and some 811A's, so used them,
but the output power is about 250 watts carrier, 275 if
I push the tubes a bit.

I wanted to run around 300 watts without pushing the tubes.
I know the difference in received signal strength would be
imperceptible, its a mental thing I guess.
(why things sell for $1.95, and not $2.00)

  
Steve (K5LTK) sent me some 8005,s in trade for some 4-400
tubes, but one arrived with a broken filament.

Do people have a lot of problems shipping tubes?


Odd, but the 8005 looks just like an 812...where do they
get the extra plate dissipation from?

I thought they were roughly the same as 812A's, but
I found out they have a 10 volt filament.
I don't have a 10 volt filament transformer.
Plus, I don't want to hack up the control deck to change
it out.
Since its on a variac, I should have got a 10 volt one to start with,
but did not have one on hand...

Maybe someday I will find another triad 10 volt 10 amp
filament transformer the same size...or close...

Looks like I am stuck at 250 watts.
What I really need is v70d's...a very good tube I guess, but
extremely rare...
  
Brett
N2DTS
 
> Brad,
> 
>    I used to run a PP 8005 rig. I eventually ran out 
> of them. seems like these tubes have finicky 
> filaments. Some would glow nice and bright, and have 
> little, or no emission. Others would work for a few 
> hours, and then lose emission. Attempts at 
> rejuvenation were less then successful.
>    This lead me down the road of other tubes, and 
> higher power levels using TVL coils. At first I tried 
> 572B's, and optimized the bias, filament V, etc. for 
> this tube. Wow, could run an easy kilowatt input. The 
> plate modulated performance was not good however. The 
> 8005's modulated much better. I had a modulator 
> capable of 600 watts, so that was not the problem.
> 
>    I later changed over to 805's with a kluged socket 
> adapter. Turns out that two 805's will run all day 
> long at 1 Kw DC input (2500V X .4A), and put out 850 
> watts of carrier. They also would modulate upward nice 
> like the 8005. This was a win -win because the 805 was 
> happy, would modulate well, and the filaments were not 
> finicky. I ran the same pair for several years. I was 
> between wives at the time so I yakked on 3880 quite a 
> bit (circa 1983-6). The max plate voltage for a 805 is 
> 1500 volts CCS. I ran them at 2500 ICAS Plate 
> modulated class C push pull. I kept the plate current 
> & dissipation within spec, and let er rip. Tubes took 
> it. 
> 
>     The bad news. The 805 has higher interelectrode 
> capacitance, is not a good tube beyond 20 meters. 
> Also, I sent my lot of 805's (six of them) to Ozona 
> Bob, w5pyt. I wonder where they ended up.
> 
> 
>     Brad, you might try the 808. Use 4 in push pull 
> parallel at 2500 volts. That is what I did for my 600 
> watt modulator. Nice stable tube that runs for years 
> without complaining.
> 
> Regards,
> Jim
> 
> WD5JKO


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From: "John Coleman" <jec@pctechref.com>
Date: Fri, 7 Dec 2001 10:14:26 -0600
Subject: RE: [AMRadio] Narrow Band FM
Message-ID: <000001c17f3a$3ea7ce60$0200a8c0@WinProxy>


http://www.amfone.net - Home of the AM Radio List.

To post or see items for sale or wanted, go to the new AM'ers Trading post below.
http://www.amfone.net/cgi-bin/ikonboard/ikonboard.cgi

Ok Bob here it is: http://www/qsl.net/wa5bxo :see the link to All About
Modulation

-----Original Message-----
From: owner-amradio@qth.net [mailto:owner-amradio@qth.net]On Behalf Of
Bob Bruhns
Sent: Friday, December 07, 2001 12:04 AM
To: jec@pctechref.com
Cc: AMRadio (E-mail)
Subject: Re: [AMRadio] Narrow Band FM


http://www.amfone.net - Home of the AM Radio List.

To post or see items for sale or wanted, go to the new AM'ers Trading post
below.
http://www.amfone.net/cgi-bin/ikonboard/ikonboard.cgi

Hi John,

Actually, nighttime HF NBFM wasn't bad on my envelope-detector receiver.  I
was surprised.  And you're right, the ease of amplification could make up
for any shortfall.  And I think with modern demodulation technology, it
could be real cool.

Cool presentation on your site, right along the same lines... or vectors...
and yours have illustrations too.

Certainly...  go ahead and repost any of my public domain postings that you
like, and others can, too.  I declare them to be public domain.  I only
reserve the right to use them in a tutorial some day.  They can stay on the
'net in any case.

  Bacon, WA3WDR

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From: Bob Bruhns <bbruhns@erols.com>
Date: Fri, 07 Dec 2001 01:03:30 -0500
Subject: Re: [AMRadio] Narrow Band FM
Message-ID: <3C105BB2.9962A216@erols.com>


http://www.amfone.net - Home of the AM Radio List.

To post or see items for sale or wanted, go to the new AM'ers Trading post below.
http://www.amfone.net/cgi-bin/ikonboard/ikonboard.cgi

Hi John,

Actually, nighttime HF NBFM wasn't bad on my envelope-detector receiver.  I was surprised.  And you're right, the ease of amplification could make up for any shortfall.  And I think with modern demodulation technology, it could be real cool.

Cool presentation on your site, right along the same lines... or vectors...  and yours have illustrations too.

Certainly...  go ahead and repost any of my public domain postings that you like, and others can, too.  I declare them to be public domain.  I only reserve the right to use them in a tutorial some day.  They can stay on the 'net in any case.

  Bacon, WA3WDR

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This page last updated 18 Jul 2001.