Date: Tue, 18 Dec 2012 10:03:32 +0200
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From: phl@netikka.fi
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Subject: Re: LF: FT-241A xtals?
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What a coincidence Dimitros!

After answering to your posting I did a search on Ebay for FT-241  
crystals and found the same seller - an order has already been made :)

Many thanks for bringing up this subject - I had lost hope already.


Paul-Henrik, OH1LSQ


Quoting Dimitrios Tsifakis <dtsifakis@gmail.com>:

> Hi Paul-Henrik,
>
>> Yes, the same thought has been on my mind for a long time now. The problem
>> is that fundamental X-tals for this frequency band are nearly unobtainable.
>> I have even tried to custom order some new ones for me and a couple of
>> friends but never succeeded - the quantities would need to be much larger
>> for this type of crystals. (They use a different kind of cut as compared to
>> crystals for say 3500kHz which can still be ordered custom fairly easily)
>>
>> Hopefully people with a stash of suitable vintage X-tals will wake up when
>> the new band opens for real and put some up for sale if they don't want to
>> use them themselves.
>
> I bought a few crystals from this ebay seller:
>
> http://www.ebay.com.au/itm/FT-241-CRYSTALS-Many-to-choose-from-You-pick-/260897401407?pt=LH_DefaultDomain_0&hash=item3cbeb26a3f&_uhb=1#ht_4373wt_1188
>
> There seem to be a few left. They are sold as-is, but I found that the
> majority of the ones I bought worked OK. There may be other sellers on
> eBay.
>
>> I'd say go for it - I have built a couple of "MO-PA" transmitters for
>> 80/160m, they are really pleasant and rewarding projects with a distinct
>> sound of their own. This is especially true if you also key the oscillator.
>
> I have built recently a similar transmitter for 40 m, using a 6CL6 and
> an 807. When I keyed the oscillator together with the PA, I couldn't
> get it to behave properly, so I added a switch to leave the oscillator
> on and key only the cathode of the PA. I only key the oscillator when
> I want to draw some attention with the home-brew sound!
>
> In general, I have had difficulty sourcing a HV transformer suitable
> for an 807. In the past, I found that one can build a voltage doubler
> or quadrupler, with modern electrolytics, it is a viable alternative.
> The 6.3 V for the filaments I found I can get from a 6 V transformer.
> Hint: it's easy to add extra turns on a toroid type transformer :-)
>
> 73, Dimitris VK1SV