[Drakelist] Fwd: Re Diversity Reception

[geoffrey mendelson]

On Aug 8, 2011, at 8:58 AM, John Brown wrote:

Probably need two antennas, two receivers and a multiplexer that can  
switch between either receiver as the signal on each antenna fades  
in and out. It was called "Diversity Reception" and was used for  
commercial RRTY (among others uses)in order to maintain a constant  
signal feed to the RTTY machines. The 2 antennas that were typically  
used were 4 acre Rhombics or similar, so they were spread out over a  
relatively broad area of land able to react to the ionospheric  
changes causing the fading. Don't see how you can do it with just  
two antennas without having them reasonably separated and some way  
of detecting the change in signal strength to select the appropriate  
antenna.


It was also used during WWII in Europe to hear the BBC over jamming.  
The jamming signals varied in strength and noise from band to band, so  
it was popular when they had them to use two receivers each on a  
different frequency near each side of the head. The stereo effect put  
the jammers off to the sides and the main signal in the middle,  
reducing the effect of the jammers.


You can do something similar with modern receivers on the ham bands by  
using a computer controlled set of receivers each with a different  
antenna. For example if you use a computer controlled transceiver as  
you tune it, the computer monitors the frequency and adjusts the  
secondary receiver as needed. Then you listen to the two receivers  
with stereo headphones one with each ear.


I don't know much about them, but one of the more famous tube  
receivers used by the US military could be modifed for diversity  
reception (it may have been a factory mod) combining two of them, but  
that was for fixed frequency reception, you tuned them both, by hand,  
to the same "channel".

This was probably what John wrote about above.

I believe MFJ has some sort of diversity reception antenna, but I know  
nothing about it other than they sold/sell it.


Geoff.


--
Geoffrey S. Mendelson,  N3OWJ/4X1GM










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[Drakelist] Re Diversity Reception

[John Brown]

Probably need two antennas, two receivers and a multiplexer that can switch
between either receiver as the signal on each antenna fades in and out. It
was called "Diversity Reception" and was used for commercial RRTY (among
others uses)in order to maintain a constant signal feed to the RTTY
machines. The 2 antennas that were typically used were 4 acre Rhombics or
similar, so they were spread out over a relatively broad area of land able
to react to the ionospheric changes causing the fading. Don't see how you
can do it with just two antennas without having them reasonably separated
and some way of detecting the change in signal strength to select the
appropriate antenna.

Interesting thought however

JB

 

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Re: [Drakelist] Fading

[Dennis Monticelli]

Yes.  Diversity reception is a well known technique, but you need a radio
so-configured or a separate box to process the inputs from the two
antennas.  The antennas must be physically separated from each other
sufficiently that a fade on one would not necessarily occur in the other at
the same time.  The good news is that the technique really does work.

Dennis AE6C

On Sun, Aug 7, 2011 at 4:27 PM, Nigel A. Gunn, W8IFF/G8IFF
wrote:

> Look up "diversity reception"
>
>
>
> On 08/07/2011 11:22 PM, Neil M Califano wrote:
>
>> This is a bit off topic, but how can two receiving antennas be used to
>> reduce fading?
>>
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Re: [Drakelist] Fading

[Nigel A. Gunn, W8IFF/G8IFF]

Look up "diversity reception"


On 08/07/2011 11:22 PM, Neil M Califano wrote:

This is a bit off topic, but how can two receiving antennas be used to reduce 
fading?

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[Drakelist] Fading

[Neil M Califano]

This is a bit off topic, but how can two receiving antennas be used to reduce 
fading?

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Re: [Drakelist] T4XC

[Richard Tucker]

Garey,
The relay came in from Mouser and I made the mod today. (The bad one was the 
Varley)  The T4XC is working fine.  Thank you for the assistance.

Rick
W0RT
- Original Message - 
From: "Garey Barrell" 

To: "drakelist" 
Sent: Sunday, July 17, 2011 12:43 PM
Subject: Re: [Drakelist] T4XC


If it's the Varley, you need a P&B (Tyco) R10-E1-Y4-V2.5k, available from 
Mouser and Digi-Key.


You'll need to add a 1.5k 1W resistor in series with the coil, otherwise a 
drop-in replacement. Look at the socket for V10, the 6FQ7 (or 6EV7). 
Remove the wire connected to Pin 6 and move it to Pin 9, add a 1.5k, 1W 
resistor between Pin 6 and Pin 9, and plug in the new relay.


The 15k ohm coil relays were failure prone, primarily because of the very 
fine wire needed for a 15k ohm coil.  The bobbin would swell,  especially 
in humid conditions, stressing and breaking the wire.  This is why T-4XC's 
that have been stored in the garage for a while often have a bad relay! 
The 2.5k ohm coil of course uses considerably larger wire.


If it's not the relay, then you'll have to look at the 6EV7 and relay coil 
wiring.  Not much else involved, the 6EV7 is 'hard switched' in TUNE, so 
the VOX isn't involved.


73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs



Richard Tucker wrote:

Garey,
No problem.  I have been halfheartedly following that TR4C thing and 
understand.
No relay click and no idle current.  Must be the relay.  I'll check it 
out. I did pull and reseat all tubes .  I also switched out V1 and 10 in 
the VOX circuit.  Still nada.


73 to all and thanks.
Rick
W0RT
- Original Message - From: "Garey Barrell" 
To: "Richard Tucker" 
Cc: 
Sent: Sunday, July 17, 2011 9:33 AM
Subject: Re: [Drakelist] T4XC



Richard -

I'm sorry.  Didn't mean to 'attack' like that.  This TR-4C that we've 
been working on for about 500 messages has about gotten on my last 
nerve!  :-) I just KNOW it's going to be something silly that I missed 
487 messages back.


Even after all that yesterday, I still didn't remember until last night, 
"Do you hear the relay click?" when you switch to tune.  And "Do you see 
IDLE current?"


If it still has one of those "Varley" British made relays, most likely 
an open relay coil, probably made by Lucas!  :-)


73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs



Richard Tucker wrote:
Sorry Garey.  I guess I assumed that it would be asssumed by those on 
the list that the PS was plugged in and the T4XC was switched on.

PS plugged in
Mode switch to SSB
All knobs set up for 40cw
It turns on with a "thunk"
AC4 has recent Heathkit shop kit installed and worked when last used.
All tubes light up
transcieve switch works as it should including switching of dial 
lights.

All pilot lights are lit up
no meter movement
will not spot
will not key on cw.
It does not do anything in any switch position except turn on
I checked and rechecked all cables and hookup detail.  Checked for bad 
connections with RCA plugs.
I am familiar with using the Drake R4 line from many years of use but a 
little brain dead from setting in 100 deg wx watching grandsons 
baseball games.
Tommorrow AM I will take it out of the case and double check that all 
tubes are  light and unplug and plug athem.  I will deoxit the mode 
switch. Thank you.


Rick
W0RT

- Original Message - From: "Garey Barrell" 


To: "Richard Tucker" 
Cc: 
Sent: Saturday, July 16, 2011 9:01 PM
Subject: Re: [Drakelist] T4XC



Rick -

Ya gotta give us more than that!!

Is the power supply connected?

Is it plugged in?

Is it turned on?

Do you hear it 'thunk' when you turn it on?

Do the tubes and pilot lamps light up?

Are ALL the tubes lit?

Does the meter move?

Does it do 'anything' in any switch position?

73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs



Richard Tucker wrote:
T4XC was working fine and sat for a while (6mo)  Hooked up with R4C . 
Switched to tune.  Nothing.  It would not go into tune.   Any 
thoughts of what I should check first?  I rocked the switches and 
double checked the cables, etc.

Thanks
Rick
W0RT








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Re: [Drakelist] drake net

[Greg Roecker]

Sundays, 2000 UTC on 7238 +/-...



-Original Message- 
From: ron 
Sent: Sunday, August 07, 2011 4:07 PM 
To: drakelist@zerobeat.net 
Subject: [Drakelist] drake net 



gang,

excuse me for this but I keep misplacing when and where is the Drake net.
(at least I know it's today ...)

can someone clue me in?

73
Ron, wb1hga

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[Drakelist] drake net

[ron]

gang,

excuse me for this but I keep misplacing when and where is the Drake net.
(at least I know it's today ...)

can someone clue me in?

73
Ron, wb1hga

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Re: [Drakelist] RCS-4

[W4AWM]

Always use lock washers under those nylon insert nuts.  I have seen  many 
come loose over the years.
 
73,
 
John,  W4AWM
 
 
 
 
In a message dated 8/7/2011 3:38:49 P.M. Eastern Daylight Time,  
k9...@aol.com writes:

I've found that any antenna, tower, rotor, etc.  device used outdoors can 
benefit from the use of stainless steel hardware,  nylon insert locknuts as 
appropriate.  You can buy it online at a price,  including shipping, that is 
less than what you can buy locally for standard,  plated hardware.



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Re: [Drakelist] RCS-4

[K9sqg]

I've found that any antenna, tower, rotor, etc. device used outdoors can 
benefit from the use of stainless steel hardware, nylon insert locknuts as 
appropriate.  You can buy it online at a price, including shipping, that is 
less than what you can buy locally for standard, plated hardware.





-Original Message-
From: Loren McCullough 
To: Richard Tucker ; drakelist 
Sent: Sun, Aug 7, 2011 11:11 am
Subject: Re: [Drakelist] RCS-4


Finally got the switch box apart.  Have to replace all the external 
screws.  even with penetrating oil I was only able to remove one without 
snapping the head off, or having to grind them off, just way too rusty.

The motor frame also is a little rusty, apparently the plastic bag was 
not as watertight as it should have been.  With the help of a little 
oil, I can move the rotor by hand now nd will let it sit and see if it 
moves more freely later.  Unfortunately, I have to replace both terminal 
strips, they are both beyond any attempt at repair.  Otherwise it looks 
good.  Will have to wait till I get the terminal strips replaced before 
I can apply any power, but this doesn't look like it's hopeless.

Loren - WA3WZR

On 8/3/2011 10:22 PM, Richard Tucker wrote:
> Loren,
> One more thing.  One of my terminal strips was all rusty and I brushed 
> it carefully with a small wire brush and scraped rust off screw heads 
> and put a small drop of
> lubricating rust remover (can't remember the name) on it and on the 
> threads when I got them backed out.  I may have replaced the screws 
> --I think I did and I cleaned the strip after the screws were 
> removed.It looked better and worked fine and is still working.  Be 
> careful of the phenolic board the strips are made out of, it can be 
> brittle.
> Rick
> W0RT
> - Original Message - From: "Loren McCullough" 
> 
> To: "Richard Tucker" 
> Cc: "drakelist" 
> Sent: Wednesday, August 03, 2011 6:48 AM
> Subject: Re: [Drakelist] RCS-4
>
>
>> Just looking for any problems or gotchas to look for.  I know it was 
>> fully operational back in the 80s when i used it last, but the 
>> antennas got taken down and the outdoor unit has just been lying 
>> around outside while I was QRT.  I know I have to replace the 
>> terminal strips, the screws are all beyond use.
>>
>> What is the best way to take it apart?  All of the screws appear to 
>> be rusted and won't loosen.
>>
>> Loren - WA3WZR
>>
>> On 8/2/2011 8:50 PM, Richard Tucker wrote:
>>> Loren
>>> I have used the RCS-4 since the 70's.  I have had to work on mine a 
>>> few times.  I bought a second one at a hamfest and have worked on it 
>>> a bit. Do you have specific questions?
>>> Rick Tucker
>>> W0RT
>>> - Original Message - From: "Loren McCullough" 
>>> 
>>> To: "drakelist" 
>>> Sent: Sunday, July 31, 2011 2:57 PM
>>> Subject: [Drakelist] RCS-4
>>>
>>>
 Anyone have any experience or insight into resurrecting an RCS-4.  
 I haven't really looked at either piece yet.  The control head has 
 been sitting in my attic for abt 20 years and the remote antenna 
 switch has been sitting outside in the elements.

 Off subject, I also have a Ham-II/CD44 rotor and control head that 
 is in about the same situation except that the rotor has been in my 
 attic since the tower crashed in the late 80s.

 Would like to get them both back in operational condition.

 Thanks,
 Loren - WA3WZR

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>>>
>>>
>>> -
>>> No virus found in this message.
>>> Checked by AVG - www.avg.com
>>> Version: 10.0.1390 / Virus Database: 1518/3806 - Release Date: 08/02/11
>>>
>>>
>
>
>
> -
> No virus found in this message.
> Checked by AVG - www.avg.com
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Re: [Drakelist] RCS-4

[Loren McCullough]

Finally got the switch box apart.  Have to replace all the external 
screws.  even with penetrating oil I was only able to remove one without 
snapping the head off, or having to grind them off, just way too rusty.


The motor frame also is a little rusty, apparently the plastic bag was 
not as watertight as it should have been.  With the help of a little 
oil, I can move the rotor by hand now nd will let it sit and see if it 
moves more freely later.  Unfortunately, I have to replace both terminal 
strips, they are both beyond any attempt at repair.  Otherwise it looks 
good.  Will have to wait till I get the terminal strips replaced before 
I can apply any power, but this doesn't look like it's hopeless.


Loren - WA3WZR

On 8/3/2011 10:22 PM, Richard Tucker wrote:

Loren,
One more thing.  One of my terminal strips was all rusty and I brushed 
it carefully with a small wire brush and scraped rust off screw heads 
and put a small drop of
lubricating rust remover (can't remember the name) on it and on the 
threads when I got them backed out.  I may have replaced the screws 
--I think I did and I cleaned the strip after the screws were 
removed.It looked better and worked fine and is still working.  Be 
careful of the phenolic board the strips are made out of, it can be 
brittle.

Rick
W0RT
- Original Message - From: "Loren McCullough" 


To: "Richard Tucker" 
Cc: "drakelist" 
Sent: Wednesday, August 03, 2011 6:48 AM
Subject: Re: [Drakelist] RCS-4


Just looking for any problems or gotchas to look for.  I know it was 
fully operational back in the 80s when i used it last, but the 
antennas got taken down and the outdoor unit has just been lying 
around outside while I was QRT.  I know I have to replace the 
terminal strips, the screws are all beyond use.


What is the best way to take it apart?  All of the screws appear to 
be rusted and won't loosen.


Loren - WA3WZR

On 8/2/2011 8:50 PM, Richard Tucker wrote:

Loren
I have used the RCS-4 since the 70's.  I have had to work on mine a 
few times.  I bought a second one at a hamfest and have worked on it 
a bit. Do you have specific questions?

Rick Tucker
W0RT
- Original Message - From: "Loren McCullough" 


To: "drakelist" 
Sent: Sunday, July 31, 2011 2:57 PM
Subject: [Drakelist] RCS-4


Anyone have any experience or insight into resurrecting an RCS-4.  
I haven't really looked at either piece yet.  The control head has 
been sitting in my attic for abt 20 years and the remote antenna 
switch has been sitting outside in the elements.


Off subject, I also have a Ham-II/CD44 rotor and control head that 
is in about the same situation except that the rotor has been in my 
attic since the tower crashed in the late 80s.


Would like to get them both back in operational condition.

Thanks,
Loren - WA3WZR

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Version: 10.0.1390 / Virus Database: 1518/3806 - Release Date: 08/02/11






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[Drakelist] need am filter for r4c

[y...@aol.com]

 

 Looking for the plug in AM filter for a R4C.
thanks
dale wt4t


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[Drakelist] Update to dial request

[kc9cdt]

Folks,
I need a  A or B loine dial to do a test on...
it can be broken, warped  scratched etc...just need to be also YELLOWED.
Thanks,
73,
Lee


 


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[Drakelist] Drake plastic main dials

[kc9cdt]

Any one know what kind of plastic the Drake  A & B line dials are make 
of???


Maybe it's ABS...since that was used a lot back then?

I'm working on something here that may be of great help to many DFrake 
owners.


73,
Lee, KC9CDT


 


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Re: [Drakelist] HC6/U

[Garey Barrell]

Most any HC-6/U crystal will 'work' in the Drakes.  The oscillation may or may not be close to the 
marked frequency, depending upon the specifications the crystal was originally designed for, and 
it's age.   But most will be within 5 - 10 khz, unless they are fifth overtone or some other weird cut.


Simplest is to plug it in, peak the preselector where it 'should' be (marked frequency minus 11.1 
MHz) and see where you find the marker.  It won't hurt anything if it doesn't work!


73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs



Neil M Califano wrote:

Will any HC6/U crystal work in the Drake 4 Line or does the crystal have to be 
for Drake?




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Re: [Drakelist] HC6/U

[Ron]

Neil,
I've plugged in a lot of "stray" and odd frequency crystals and they have all 
worked.  That said, the correct "version" of crystal will provide much better 
band to band calibration.  The frequency calculation as to where you are tuned 
is much easier too.

73
Ron WD8SBB

--- On Sun, 8/7/11, Neil M Califano  wrote:

> From: Neil M Califano 
> Subject: [Drakelist] HC6/U
> To: Drakelist@zerobeat.net
> Date: Sunday, August 7, 2011, 2:21 AM
> Will any HC6/U crystal work in the
> Drake 4 Line or does the crystal have to be for Drake? 
> 
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