Amps
[Top] [All Lists]

[Amps] SB220 T/R relay substitution

To: <amps@contesting.com>
Subject: [Amps] SB220 T/R relay substitution
From: Ian White, G3SEK" <g3sek@ifwtech.co.uk (Ian White, G3SEK)
Date: Fri, 15 Nov 2002 16:25:35 +0000
Tony Wanschura wrote:
>Does anyone know how much delay there is on the IC765 and 746 between 
>PTT signal and RF output?

On the 746 in all modes, it's about 12-14ms between the first 
key-down/PTT and the start of RF output. The HSEND/VSEND outputs on the 
DIN accessory sockets are the fastest for amp control, and they go low 
about 5-6ms after key-down. The phono output is slower, even when not 
using the relay.

In semi-bkin, while the rig is still in TX mode, the RF runs about 7ms 
behind the key-down. In full bkin, every key-down is like a "first", so 
the RF always runs 12-14ms behind key-down. RF always ends about 2ms 
after the key-up.

So if you use HSEND/VSEND to key the amp, you have about 6ms for the amp 
to get ready. That's just enough time if you use fast RF relays, or some 
kinds of relays speeded-up.


I also have data for the FT-990 (not good) and would like to collect 
more. In particular, does anyone have timing data for the FT-1000 models 
- especially the MP?

(Or if anyone in my part of the UK is prepared to lend me their MP for a 
day, I'll happily measure it here!)


-- 
73 from Ian G3SEK         'In Practice' columnist for RadCom (RSGB)
                            Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek

<Prev in Thread] Current Thread [Next in Thread>