[Boatanchors] Drake 2B General Coverage (Addition)
Carl
km1h at jeremy.mv.com
Thu Jul 7 12:12:43 EDT 2011
While I agree with most Dave the 390A mechanical filters are not that bad
otherwise the military wouldnt have used then for the long, long product
life. Nor would they have been in the A and S line, xcvrs, etc
The real reason for the R-725 was the group delay thru the filter that
affected the crypto data decoder for the NSA. This also occurs in multi pole
crystal filters.
While the 390 sounds good on full signal AM the 390A is the choice for
battle conditions on any mode and selectivity position due to the sharper
skirt selectivity.
Neither one is a comfortable to use band scanner unless you enjoy cranking
that gear train day after day. Ive owned a 390A for over 20 years but it
gets very little use any more. Plus working on hundreds of them in the Navy
and later for a large civilian reseller I got to know both models
intimately.
Carl
KM1H
----- Original Message -----
From: "David C. Hallam" <dhallam at knology.net>
To: "Carl" <km1h at jeremy.mv.com>
Cc: <boatanchors at mailman.qth.net>
Sent: Thursday, July 07, 2011 10:26 AM
Subject: Re: [Boatanchors] Drake 2B General Coverage (Addition)
>
>
> On 7/7/2011 9:10 AM, Carl wrote:
>> The 390 is well above the ability (mechanical mostly) of many and was
>> even a nightmare at the tender overhaul level in the Navy and Im sure in
>> other services and quickly replaced by the 390A.
>>
> I'm sure everyone has their favorites. I had a R-390 for 40 years until I
> reluctantly sold it last year as part of a downsizing due to lack of
> space. My only objection to it was its weight if it had to go to the
> bench which was rare. The only service problems I had with it was antenna
> rectifier which I replaced with some modern diodes, the 50 ohm 2W
> resistors in the cathode of the voltage regulator, the short life and high
> cost of the 26Z5W rectifier tubes and the ballast tube. I replaced the 2W
> resistors with 5W, put Copper Top SS rectifiers in for the 26Z5W tubes,
> replaced the 6BA6's in the PTO and BFO with 12BA6's and put in a piece of
> wire to jumper the ballast tube. The ballast tube is absolutely
> unnecessary for fixed station use. Not bad for 40 years of use.
>
> I never had a mechanical problem with the admittedly complicated gear
> train. The depot service manual was clear on how to adjust the gear train
> if needed. I checked it out when I got the radio and that was that.
>
> For SSB reception I had a CV -579 converter.
>
> It was a sad day when the new owner came to pick it up.
>
> The R-390A is not as good for a general coverage receiver due to the
> mechanical filters Collins used as part of a general cost reduction design
> of the R-390. The filters introduced some ringing. Due to a phase shift
> in the mechanical filters, the military had to come up with the R-725
> which was a R-390A with the IF strip from a R-390. At one point I
> modified a R-390A IF strip with the filters so it could be used in my
> R-390. It didn't stay in the R-390 for long.
>
> David
> KW4DH
>
>> The R-388 /51J3 or 51J4 would be my choice for a good SWL band cruiser of
>> the Collins military family.
>>
>> The HQ-180/180A is still a good radio and has been the subject of much
>> discussion. They dont require recapping and the main problem is SMD in
>> the IF cans which is a straightforward fix if/when it occurs. The
>> optional Noise Silencer is a plus.
>> If SSB isnt a big interest the HQ-145 is basically a 180 without the
>> HC-10 SSB adaptor built in. It still works on SSB the old way.
>>
>> A real sleeper which has been showing up often recently at a low price is
>> the Hallicrafters SX-73/R-274. Superb quality unlike anything else from
>> Halli and easy to work on. Same tuning ranges as the SP-600/R-274 of BCB
>> to 54 MHz but far superior quality and performance.
>>
>> The SX-62 was designed as an upscale homeowners AM BCB, FM BCB and SWL
>> radio. It tunes from 530 KHz to 108 MHz continuous. The downside is that
>> it shares with the SX-42 of being the hardest Halli to refurb. My primary
>> general coverage all band cruiser is a SX-62A.
>>
>> Carl
>> KM1H
>>
>>
>> ----- Original Message -----
>> From: "David C. Hallam" <dhallam at knology.net>
>> To: <boatanchors at mailman.qth.net>
>> Sent: Thursday, July 07, 2011 8:05 AM
>> Subject: Re: [Boatanchors] Drake 2B General Coverage (Addition)
>>
>>
>>> Joe,
>>>
>>> You are finding the shorting comings of the 2B as a general coverage
>>> receiver. It was designed as a ham band receiver. For that purpose it
>>> is excellent. If it's within your budget and you want to stay with a
>>> tube type receiver, the R-390, not the R-390A, is the best you can get
>>> for a general coverage receiver.
>>>
>>> David
>>> KW4DH
>>>
>>> On 7/6/2011 8:59 PM, Joe Connor wrote:
>>>> I should add that another shortcoming of the 2B is that it cannot
>>>> receive below 3.5 mhz without a special low frequency converter. That's
>>>> a shame because it seems this would be a great set for BCB DXing.
>>>>
>>>> Here are some details on the converter:
>>>> http://www.dproducts.be/drake_museum/2-lf1.htm
>>>>
>>>> If anyone has one for sale, please let me know.
>>>>
>>>>
>>>> Joe Connor
>>>>
>>>> From: Joe Connor<joeconnor53 at yahoo.com>
>>>>> To: Mail List - Drake Gear Drake Gear<drakelist at zerobeat.net>
>>>>> Cc: "boatanchors at mailman.qth.net"<boatanchors at mailman.qth.net>
>>>>> Sent: Wednesday, July 6, 2011 8:01 PM
>>>>> Subject: [Boatanchors] Drake 2B General Coverage
>>>>>
>>>>> OK, guys, I have been using my Drake 2B as a general-coverage receiver
>>>>> for a week now and I wanted to report back on my experiences. This is
>>>>> a receiver that you folks helped me out with about a month ago. To
>>>>> repair it, I had to install a 6BF6 tube (easily obtained) and replace
>>>>> the filter cap can.
>>>>>> I made it a general-coverage receiver by using the accessory crystal
>>>>>> sockets B, C and D. A 10 mhz crystal gives me 49m, a 13.5 mhz crystal
>>>>>> gives me 31m and an 8.0 mhz crystal gives me 25m. The stock crystal
>>>>>> for 40m includes the 41m band. The receiver's sensitivity and
>>>>>> selectivity are very good. The tuning is spot-on accurate. While the
>>>>>> audio does not rival that of an SX-28 or NC-183d, it is more than
>>>>>> acceptable. I am really impressed. This receiver is a keeper. I have
>>>>>> this set in my study and use it for general SWLing as well as
>>>>>> monitoring the ham bands. It's a fun set to use.
>>>>>>
>>>>>> There are shortcomings:
>>>>>>
>>>>>> (1) you have to buy the crystals for each SW band;
>>>>>>
>>>>>> (2) it's a royal pain to change crystals. The 2B's top does not open,
>>>>>> which would make changing the crystals less of a chore. Thus, I am
>>>>>> pretty much limited to the SW bands listed above. This is a
>>>>>> significant limitation. For example, I would like to be able to
>>>>>> monitor the 19m band; and
>>>>>>
>>>>>> (3) I have yet to master the 2B-Q Q multiplier.
>>>>>>
>>>>>>
>>>>>> Joe Connor
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>>>
>>> --
>>> "I predict future happiness for Americans if they can prevent the
>>> government from wasting the labors of the people under the pretense of
>>> taking care of them."
>>> Thomas Jefferson
>>>
>>>
>>> "We may consider each generation as a distinct nation, with a right, by
>>> the will of its majority, to bind themselves, but none to bind the
>>> succeeding generation, more than the inhabitants of another country."
>>> Thomas Jefferson
>>>
>>>
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>>
>>
>
> --
> "I predict future happiness for Americans if they can prevent the
> government from wasting the labors of the people under the pretense of
> taking care of them."
> Thomas Jefferson
>
>
> "We may consider each generation as a distinct nation, with a right, by
> the will of its majority, to bind themselves, but none to bind the
> succeeding generation, more than the inhabitants of another country."
> Thomas Jefferson
>
>
>
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1388 / Virus Database: 1516/3749 - Release Date: 07/07/11
>
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