KE4MOB: Where could I find info about the AGC mod for the 450?

Just an observation about the receiver in the 450:
over the years, I've read a great many comments from knowledgeable users about RX performance. The observations fall into 2 very distinct categories: excellent or so-so (noisy, a bit insensitive and 'hot' as described by KE4MOB). I've come to the conclusion that the reason for this is that there is quite some variability among individual 450 units.

Fortunately, mine is certainly a good one and isn't hot noisy or insensitive; this has been confirmed by RF comms professionals with far more experience and better 'ears' than me.

I suggest that if you are looking at a 450, it would be best to test drive a few individual units and see if each one 'smells' right to you; if one doesn't then it may well be an average and not an excellent unit and perhaps ought to be avoided in favour of another...

Indeed this advice probably applies generally; I'm firmly convinced that even in this age of mass production electronics, there is still significant variability between individual units.

EI4HQ

Personally I like the slope-tune better; the lack in the 450 is a shortfall. That said I don't think I've ever not worked a station because I didn't have slope-tune on the 450... though it would probably have been easier with it ;o)

As regards the comments made by W6EZ, I'm not aware of most of the things mentioned, but obviously they may matter to you. Subject to my comments in my original posting, I'd probably pitch for the 850 too -my allegiance to the 450 is clouding my judgement ;o)

EI4HQ

I've owned a TS450SAT since 1993 and used a TS850 in contests regularly over the years.

As best I can remember...

The TS450 has no internal keyer, no tunable passband filter, no MOX and no auto-notch (does the 850 have an auto-notch? I'm not sure). The TS450 is quite a bit smaller and consequently suffers a bit ergonomically (but wins in the portability stakes). The alc on the 450 is a bit peaky and the s-meter a bit insensitive (at least on my one).

Other than that, I reckon they are identical. Both rigs share the same 'business' internals i.e. RX and TX and it is worth noting that the RX in this family of rigs is particularly good for JA equipment. They are also durable and reliable. They are still very popular and I'd get my hands on either if the opportunity permits. I'm looking out for a good base station rig and the 850 is at the top of my list.

Either would be an excellent choice: to be frank I'd base the decision mostly on whether you are looking for a base-station rig (850) or one that can be easily moved (450). The differences otherwise are pretty trivial.

The 'windom' is basically a top-loaded vertical: this will definitely need a tuner.

The OCF-dipole, often incorrectly called a 'windom', doesn't require a tuner on the fundamental band but does need a 1:1 balun to match the co-ax to the wire so as to avoid currents flowing on the co-ax screen.

73
EI4HQ

Hullo,

I'm building an OCF (off-centre fed) dipole for local 40m work.

I need to make a 4:1 current (choke) balun for it but am left a bit unsure as to how to go about it. I don't want to buy one! Unfortunately on this one point the ARRL Antenna Book is as clear as mud. It gives loads of examples of 1:1 current baluns and an example of a  4:1 'balanced' balun (how can you have a balanced BALanced to UNbalanced transformer?) but as far as I can figure no indication of how to build a 4:1 current balun.

Any quick pointers (cores/windings etc) appreciated.

73
Cormac, EI4HQ

Hi,

I operate a 25w beacon on 28.209MHz (EI0TEN). Unfortunately, I've recently had to relocate the beacon to my home qth and here it'll remain for the foreseeable. Consequently my ability to operate on 10m (and to a lesser extent 12, 15, 17 and 20m) is significantly compromised.

Any suggestions for how I can best filter out the 28.209MHz transmissions in the rest of my station? I've looked at Dunstar filters etc. which are fine for the bands other than 10m. What can I do about 10m however? Is a very narrrow bandstop filter a possibility (i.e. built to stop 28.209MHz)?

Any advice and/or suggestions appreciated.

Cormac, EI4HQ

Hi,

I operate a 25w beacon on 28.209MHz (EI0TEN). Unfortunately, I've recently had to relocate the beacon to my home qth and here it'll remain for the foreseeable. Consequently my ability to operate on 10m (and to a lesser extent 12, 15, 17 and 20m) is significantly compromised.

Any suggestions for how I can best filter out the 28.209MHz transmissions in the rest of my station? I've looked at Dunstar filters etc. which are fine for the bands other than 10m. What can I do about 10m however? Is a very narrrow bandstop filter a possibility (i.e. built to stop 28.209MHz)?

Any advice and/or suggestions appreciated.

Cormac, EI4HQ

As life involves compromise, I'm currently installing my shack in a room built into the roof-space of my new house, 5.5m (18') above ground.

I have a 1m x 1m copper plate on an internal wall onto which all equipment will ground for both DC and RF. That plate is connected to ground via a 250mm (about 1') wide copper strip of length 7.2m (23.5') which at the ground end is connected to both deep ground rods for DC earth and a network of 20 short rods connected together with braid just below the surface over a wide area for RF ground.

Obviously I'm ok for DC ground but the rf ground is another matter. Given the length I have, I expect to have poor rf ground on the 30m and 10m bands and ok but not great rf ground on the 20m and 12m bands. This prediction is based on the high impedence rf path I expect on bands where the path to ground length is odd multiples of 1/4 wavelength.

Whether I'll have problems in reality remains to be seen - it'll be a few weeks before I can put my theory to the test...

What I want to ask is:

Does a poor rf ground in any way affect reception? i.e. even if I don't lend up with a 'hot shack' on transmit, is my rf ground as described likely to compromise my reception capability on certain bands?

I'm currently designing the radio station for my new QTH (currently under construction).

What are peoples recommendations for a 5 band (10,12,15,17 & 20) beam which has a boom length no greater than 18'?

[Force 12 do the C3, C3E, C4, C4E, XR5. Hygain do a series of Log periodics (LP1009X) but I  don't have boom length info... Cushcraft don't appear to do one?]

Any experience would be appreciated.

Cormac, EI4HQ
Cork, Ireland

Funny,
I worked PJ2/DF7DF (if I've remembered the call right -anyhow it was the PJ2/D station thats been on air this past week) and despite *numerous* attempts on my part to correct the operator my call was being copied as EI4SQ instead of EI4HQ... now PJ2 is a new one for me and I'm only a few confirms short of DXCC so they all really count right now. However the op. was working a lot of stations, he was weak enough with me, I was only running 100w into a 1/4 wave ground mounted vertical so the error is understandable... yes its frustrating but THATS DX!  I certainly wouldn't hold any grudge agin the operator - I'm just grateful he/she is out there making the rare ones available )
NIL is a fact of DX life - I'm sending a card in the hope that the call was correctly copied and there was just a bit of cw fist fatigue going on...
Chalk it up! It WILL happen again and probably with an incredibly rare one like VP6DI - I spent a lot of time listening to that operation and the number of seriously dodgey qso's was quite unbelieveable - many ops. suffering from a serious dose of wishful thinking that'd they'd worked the DX...
73
Cormac, EI4<<H>>Q )

FOLLOW UP:
Problem solved. Thanks for the offers of help
Cormac, EI4HQ

G'day all,

This is one for the  real anoraks/nerds/IT pros out there:

I'm posting here because the problem is preventing the successful revival of a crucial DX cluster node in EI...and I'm desperate )

I'm an IT pro myself so don't be afraid to get in under the covers and give me messy suggestions; at this stage I'm prepared to try almost anything. 2 guys have put 4+ months and serious hours into this project and we ain't happy right now )

I bring up a telnet connection across a LAN to a server (Red Hat Linux) from DXTelnet running on a Win2K workstation. The local server is performing a firewall type roll i.e. the workstation cannot telnet direct to the outside world but only via an account on the server. THERE IS NOTHING I CAN DO ABOUT THIS SITUATION.

I then bring up a second telnet connection to an external dx cluster (connecting in NODE mode). This connnection passes through another (supposedly) transparent firewall - good innit ) AGAIN THERE IS NOTHING I CAN DO ABOUT THIS SITUATION.

Now the problem: At some stage during the process a second unwnted local echo is being introduced. This additional echo is causing havoc with the Cluster protocols/data transfer... unfortunately its proving very difficult to pin down. We need to supress at least one of these local echoes but can't seem to get any success...

Can anyone help me out here - the security setup is relatively standard in big corportates/institutions and perhaps someone may have a blinding flash of insight?...please....ah you will think about it won't you...I'm desperate...HELP! )

Cormac, EI4HQ
Cork, Ireland

PS: This problem is not apparent if I use the Win2K telnet client - I don't think its  a problem within DXTelnet - we've spoken in detail with the author but at the same time I can't pin down why it occurs in DXTelnet but not in the Win2K Telnet client...
C.

Quickie...(he who is too lazy to go and look up about WriteLog and hey seeing as how I'm here...)

Does WriteLog network for multi-multi ops? Whats the network latency like? This has always held back my club as there was Windows based stuff but it didn't network or if it did the network delays were insufferable during a seriously hot run.

Of course there is the added attraction of DOS based s/w that its very light on h/w requirements...

Well I've worked in the computer science arena for years and reckon;

There's lots of OS's - pros and cons to them all. I use Linux, Win2K and OS9 regularly depending on what I'm doing.

No OS has got the "its just a tool and I want to get on with it" interface/transparency of use anywhere near right yet - even MAC - in actual fact MAC is now well down those stakes compared to recent Win & Linux offerings (IMHO)

Software writers favour PC simply because of the chicken & egg situation with market share - the more potential users the more likely people are to write for the platform the more likely an increased number of people are to use the platform etc. etc. etc...

As regards s/w for the MAC well I reckon in 5-10 years the h/w will be so fast that all code will be interpreted and platform independent (ie what JAVA is attempting to  with the JVM - but it'll acutally be fast enough to be of some serious use). Indeed I use a G4 regularly that runs an interpreter verision of Win98 in a window - pretty damn quick as well - really neat!

I was never one for MS bashing or "Linus Torvalds bashing" - doesn't have the same ring to it ;O) as I've always felt that MS have made some significant contributions to the world of IT - say datacentric programming or OLE for example...

Horses for courses I guess - unfortunately we live in a world driven by market share & lots of lemmings )

G'luck & don't conform...
73
Cormac, EI4HQ

Suck it & see!

I've had antennas in amazingly BAD set-ups in the past that have performed reasonably well (I couldn't even begin to model some of the situations) and some design perfect antennas (particularly a 40m dipole up at 1/2 wavelength, parallel to ground, no obstructions anywhere nearby) that didn't "fly" at all...

I'd suggest going vertical though - generally you'll do much better all-round (DX & local). At 17m, verticals are a reasonable size also. Though I'm lucky to have a very good setup nowadays I still have the old reliable triband vertical for 10,15 & 20 as sometimes it does a better job than all the fancy yagis in the world...

G'luck & keep experimenting with antennas - great fun )

Cormac, EI4HQ
Cork, Ireland