K40 antenna any good

This is the place to discuss any general CB radio related topics. Getting started, installations, operation etc.
User avatar
prettypolly
Top Poster
Top Poster
Posts: 1021
Joined: 09 Jan 2013, 01:57
Call Sign: 26FB185

Re: K40 antenna any good

Post by prettypolly »

It could make a 1/4 wave ant with a modification
wa10
Top Poster
Top Poster
Posts: 1346
Joined: 19 Feb 2008, 00:37

Re: K40 antenna any good

Post by wa10 »

The Collector,
my t40 was on a magmount, i can't remember what the mag looked like, seem to remember a rounded groove that the bearings clamp into & a chrome dome, but that's all.
W8JI
"An antenna with a poor ground using few radials cannot have a support mast grounded to the radial common point (at least it shouldn't if designed properly) There is no exception to this!
User avatar
cb4ever104
Legend
Legend
Posts: 6551
Joined: 28 Jul 2011, 21:26
Location: Alicante , España

Re: K40 antenna any good

Post by cb4ever104 »

For me the K40 is the Cobra 148 GTL-DX of the antenna world . Sure , it isn't the best CB antenna out there , and they're easy targets to punch holes in . But for me it's a piece of iconic CB equipment that's got classic written all over it . Well actually it's got K40 written all over it :) . Every time I twist that little coil onto it's base I get thrown back to the late 70s when it all began . And for me that's what it's still all about . Nostalgia ! :)

Sammy
30TM060
Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.
canuck777
Regular
Regular
Posts: 30
Joined: 27 Sep 2015, 18:57
Call Sign: 2e1mha
Location: Worcester city.
Contact:

Re: K40 antenna any good

Post by canuck777 »

prettypolly wrote: 09 Jun 2018, 19:17 Hi i want to ask is the k40 antenna any good or is there better ones out there ..
Hi, for what they are - A based loaded shortened whip, they work very well. i'll give you an example. years ago, a blind cb and ham friend of mine had a converted uk 27/81 rig on the fm portion of the 10 meter band, 4 watts out into mobile K40 literally on a bisquit tin lid :clap: with no ground plane wires, on the carpet on his living room floor. he put out a call and a mid west USA station came back 5+9 and gave him a 5+9. solid copy for 15 minutes like he was down the road. with such a very poor ground plane indoors ground floor as well, it proved the K40 can deliver. ok there was good skip conditions but even so ...
The Collector
Legend
Legend
Posts: 8666
Joined: 23 Jan 2010, 19:26
Location: Bristol-ish

Re: K40 antenna any good

Post by The Collector »

wa10 wrote: 12 Jun 2018, 21:56 The Collector,
my t40 was on a magmount, i can't remember what the mag looked like, seem to remember a rounded groove that the bearings clamp into & a chrome dome, but that's all.
Ok cheers for the info. I'll keep looking on ebay.

My Espace's hatch edge is fibreglass so I was obviously unable to fit the hatch mount to it. If I could make a t40 to SO adapter base it'd be my weapon of choice for mobile use but it'd be almost impossible for me.

I ended up drilling through the steel roof and putting an SO mount on there. There are fibreglass, steel, aluminium and plastic panels on the bloody thing to save weight!

One day, I'll get myself a Sirio 4000/5000 turbo, but for now a 49p Mil145 thing will suffice.
The Collector
Legend
Legend
Posts: 8666
Joined: 23 Jan 2010, 19:26
Location: Bristol-ish

Re: K40 antenna any good

Post by The Collector »

One thing to mention when buying a well-used K40 is thst the mount can become a bit slack and not as tight as when new. If vibrated, especially with the UK's potholed roads, there is a very slight risk of it coming loose and falling off. You can use a thin ring of rubber on the mount to help make the fitting a bit more snug and tight.

This is the reason I preferred the t40 back in the day with it's better (and lockable with a little security key to stop it getting swiped as easily) twist-ring mounting system as well as its tapered whip that didn't sway about half as much.

The performance was exactly the same as the K40 though which won't be a surprise to anyone.
Post Reply