[TMC] Is this list still active?

Tue Dec 15 14:20:17 EST 2020

    The Treetop circuit is a small board that fits in place of 
the BFO tube. Requires some re-wiring but not much. You lose the 
noise limiter but its not effective on CW and SSB anyway, not a 
big deal. The NL tube is simply removed. The AM detector is 
changed from a tube to an SS diode. Probably no effect on 
performance.
    The fellow who runs Treetop is accessible via phone. Talked 
to him  a couple of times. He has some ideas about the 
R-388/51J-3. He suggested to me that the correction for the VFO 
would be made better by adding a small capaccitor rather than 
removing turns from the coil. I found this same suggestion buried 
in the stuff on the Collins Collector's web site. I have yet to 
try it on mine. If it works it would preserve the linearity of 
the VFO. I also want to try changing the load capacitor across 
the crystal filter to see if it can be zeroed on 500Khz. The 
entire scheme of the receivers requires the IF to be at exactly 
500khz so one can't use the trick of tuning the IF to the crystal 
filter frequency.  In mine the BFO coil has some play. I want to 
get into the can and see what is loose.
     I am stuck, as are others, by lack of space, and to be 
frank, with lack of energy. However, I really want to get this 
receiver as perfect as I can.
     I found your comments on the GPR-90 of considerable 
interest. I have been curious about them ever since the saw on at 
Henry Radio when they came out. I think TMC made a serious 
mistake in their advertising in stressing they were not frequency 
meters, etc. I suspect they are better receivers than their 
reputation. Obviously, there were problems because the changes 
made to the RXD were evidently aimed at fixing them. Particularly 
the re-designed front end and BFO. Whatever else they are among 
the handful of the sexiest looking receivers ever built.
    The entire manual is on the Treetop web site.

On 12/15/2020 7:45 AM, Larry wrote:
> I've seen that circuit board on Ebay.  Have a nice overhauled 
> R-388 that i was wanting to put it in but not sure how or where 
> it would fit.
>
> I still have a PAL-500 amp, power supply and interconnect cable 
> to part with for $750.  I also have a nice, real clean and very 
> nicely calibrated
>
> GPR-90 that i seldom use for $550.  It would like a good home 
> as well since i'm trying to downsize big time.  Hate to give up 
> my TMC gear after lusting for
>
> it for so long but the time has come.  Shipping the PAL 500 
> power supply could be a problem as most of you know due to it's 
> weight so if someone buys it we would have to work out a means 
> of passing it along.
>
> Larry W0OGH
>
>
> On 12/14/2020 6:07 PM, Richard Knoppow wrote:
>> Forgot the link for Treetop
>> <http://www.treetopcircuits.com/pmwiki/pmwiki.php/Main/Products>
>>
>> On 12/14/2020 3:22 PM, Grant Youngman wrote:
>>> Yes, I really like my GPR-90.  Around 5 years ago I relocated 
>>> cross country and passed on almost all of my BA RX/TX 
>>> collection before moving.  The GPR-90 and accessories was one 
>>> of 3 radios I couldn’t bring myself to part with.  I also 
>>> have left a 51J4 with Dallas Lankford SSB mods (published in 
>>> HSN) and a nice 9.5 KHz mech filter for AM.  Also, but not 
>>> least, a Drake 2-B.  It’s all there is now … not many, but 
>>> good ones :-)
>>>
>>> Grant NQ5T
>>>
>>>> On Dec 14, 2020, at 5:55 PM, Dave McDonald 
>>>> <jdmcd at frontier.com> wrote:
>>>>
>>>> I still monitor.  I also have the GPR-90 and GSB-1 plus 
>>>> speaker.  Great radios.
>>>>
>>>> Dave
>>>> K4EWC
>>>>
>>>> Sent from my iPad
>>>>
>>>>> On Dec 14, 2020, at 5:17 PM, Grant Youngman 
>>>>> <ghyoungman at gmail.com> wrote:
>>>>>
>>>>> Just checking.  Rejoined after quite a long time away. But 
>>>>> I don’t see anything new in the archive since last October.
>>>>>
>>>>> One of my favorite radios is the GPR-90.
>>>>>
>>>>> Grant NQ5T
>>>>> GPR-90/GSB-1/GSP-1
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-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL