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RE: KT88 Tube coil

Hello Nick,et al,
               Well I'm one of the few and almost none then!

Cos I have built and operated valve TX's on the Ham bands for the last 17
years!

Your are quite right though,  There are very few hams building there own
gear these days, and frankly the hobby is dying in the UK

Most of the amplifiers I made were for the VHF and UHF bands, and used
ceramic/metal forced air cooled, external anode tetrodes such as the 4CX250B
and 4CX1000A

These are 250W and 1000W anode (plate) dissipation resp. and both are quite
easy to find if you know where to look.

I dont think there are many coilers powering tube coils with these sort of
tubes though.
The sockets (bases) tend to be pricey and the need for continuous air and
good power supplies can be a put of, though I know that Richard Craven has
built a tube coil powered by a 5CX1500 power pentode

As for the ubiquitous KT88 there are plenty to be seen around at the radio
rallies, but the bigger audio tubes are rare, and fetch high prices.

I think once you go beyond the KT88 power level, it's pretty much design
your own tube driven TC, though I'm sure most circuits will scale-up if the
components are beefed-up accordingly.

BTW, If anyone is looking for big transmitting tubes and bases, I have lots
to sell, as I'm scaling back on my ham radio pursuits.

One of the best rallies for tubes is the Elvaston Castle rally near Derby,
2nd weekend in June.

I've picked up some great bargains at this rally before!

                        Cheers, Martin G6ABU      TCBON

> ----------
> From:         Tesla List[SMTP:tesla-at-pupman-dot-com]
> Sent:         Wednesday, March 10, 1999 7:37PM
> To:   tesla-at-pupman-dot-com
> Subject:      KT88 Tube coil
> 
> Original Poster: NickandSim-at-aol-dot-com 
> 
> To All,
>           in the uk very few radio hams build their ownTXs and almost none
> use
> valve TXs so you just can't get big transmitter tubes.  The biggest tubes
> I
> can easily buy are the KT88 tetrode (70W) and the EL34 pentode (30W).  Are
> their any tube coils designed for these or other audio tubes?
> Thanks in advance
> 
> Nick Field
>