| |
VK6BE > TECH 05.06.07 09:33l 40 Lines 2196 Bytes #999 (0) @ WW
BID : FC1002VK6BE
Read: GUEST OE7FMI
Subj: Re: HF Rx Suckout Trap
Path: DB0FHN<DB0MRW<DK0WUE<DB0RES<IK2XDE<IW2OAZ<IV3SCP<SR1BSZ<WA7V<KD4YAL<
VK2TV
Sent: 070605/0804Z @:VK2TV.#MNC.NSW.AUS.OC #:12898 [Kempsey, QF68JX] $:FC1002VK
From: VK6BE@VK2TV.#MNC.NSW.AUS.OC
To : TECH@WW
That is interesting to see this device reintroduced after 50 years. We
used to use these traps on BC receivers owned by the neighbours in the
1940s and 50s to get rid of BCI. When I first got my ticket 50+ years ago
I had a dear old lady ring me saying that when she sat down to listen to
her favourite serial on her BC radio there would be a whistle and then she
could only get my voice on her radio.She said she had no sooner turned on
the radio when she said, "Oh no. Here he comes again!"
I went to have a look and to my horror the old lady's radio was a 1928
Gulbransen - two or three RF stages and a detector with a couple of audio.
It had some very interesting bits on the chassis including some very
ancient valves that looked as if they were the originals. The thing worked
well but it was a wide as a barn door.
I built a simple filter resonating on 80 metres (the offending frequency)
using an ordinary BC tuning capacitor and a coil. That fixed the problem.
One happy old lady and one even more happy amateur - me!!
In the early days of TV in this state also there was some problem with TVI
especially when the TV watchers were situated about 100 miles from the
station which was on VHF. Some of the watchers were my family in another
room who objected to the interruption to Doctor Who when I called on air.
Frequently the problem could be cured by winding a few turns of 22gge
coper wire on a pencil and mounting it across the TV antenna terminals.
This shorted out the HF signal but let the VHF TV signal through
unimpaired.
Those days are over. TVI is something of a rarity these days here.
Bob VK6BE.
> y G8MNY (Updated Jun 07)
> (8 Bit ASCII Graphics use code page 473 or 850)
> When doing demo stations with more than 1 Tx on different bands (or with a nearby ham), QRM between
stations is quite normal, even with the high Q tuned circuit of an ATU.
> Here is one method to remove most of the problem from the aerial lead. (from a system built up for 2
FT101s by G0SYR years ago & revisited for > more modern rigs.)
> Why don't U send an interesting bul?
> 73 de John G8MNY @ GB7CIP
Read previous mail | Read next mail
| |
