Posted by: "JOHN MACKEY" <mailto:[EMAIL PROTECTED]
Re%3A%20Johnson%20PPL%206060%20manual%20needed>[EMAIL PROTECTED]
<http://profiles.yahoo.com/jmackey_usa_net>jmackey_usa_net
Wed Feb 21, 2007 8:26 pm (PST)
are you saying a 45-470 MHz PPL6060 will work in the 420 MHz range?
Absolutely!! I've moved many an EFJ to 420 operation - 558, 559,
6060. And some of them began life as T-Band units, 470-512 MHz. In
the RX, use high side injection xtals. Matter of fact, use your
existing 440 or 450 xtals to test with. The radio will hear a
signal -21.4 MHz lower than your current freq. You may have to add
a 1/4 turn to each coil in the multiplier helical. In the front
end, use a 1/4 turn for 427-433 range and a half turn for the low
end. We used regular house wire, 10 ga I think for the 558/559
units, formed around the proper sized drill bit. Tack solder it to
the end of the existing coils. They tune right up. Sometimes, 1/4
inch longer screws is all it takes. If they are T-Band, use more coil.
On the TX, some padding in parallel with caps in the multipliers is
needed to bring them in range, especially if TX'ing low. It is easy
to get a doubler acting like a tripler, so be sure to have a
spectrum analyzer on hand to verify what freq the RF is on. Same is
true for the amplifier stages. Two of the helicals in the 6060
casting are for TX and may need the coil extension trick like the RX
side. They make good 420 full duplex link radios, similar to a modified MVP.
- mike - w5jr
