Larkspur A41 manpack Radio and Soviet Airborne P-254 manpack radio

This is serious beard territory.

@Roadster280 @greenbaggyskin

I'm too young ( :D ) to have worked on Larkspur, per the OP.

However... (and you, as a licensed Radio Amateur either definitely know this, or bluffed your exam), the success or otherwise of HF skywave propagation is almost entirely dependent upon frequency. The frequency will be somewhere in the HF Band, 3-30MHz, depending on range, takeoff angle (largely determined by proximity to ground relative to wavelength), time of day and sunspot cycle.

The "f/234 plus 8ft" calculation gets you in the ballpark, the "plus 8" is to account for the antenna tuner. That will load/match the antenna either capacitively or inductively (or both). Capacitively loading the antenna makes it appear shorter, inductively loading it makes it longer. Tunable capacitors are lot easier/cheaper to build than tunable inductors, so making the antenna longer and shortening it is preferable to "lengthening" it. The tunable inductor in a Clansman TURF is a work of art.
 
This is serious beard territory.

@Roadster280 @greenbaggyskin
Thanks for the mention, but just how old do you think I am? Larkspur? I remember the older guys laughing about how temperamental it had been, while reminiscing fondly about its foibles, but I was not that callsign I'm afraid.

I'm going to have a play with that formula though and see what it throws up. I assume it is the frequency in kilohertz, with the resultant antenna length in feet.

ETA: Just saw the follow-on post by @Helm with the antenna calculator. 234 divided by F in MHz +8 (Feet), gives a roughly 1/4 wavelength antenna, that would be tunable. Very good, but I prefer metres myself. I can mostly work it out quickly in my head, but who doesn't have a calculator to hand nowadays?

Further ETA: Just saw @Roadster280 post above ref tuning and totally agree. Smart lad he is, you should listen to him.
 
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Thanks for the mention, but just how old do you think I am? Larkspur? I remember the older guys laughing about how temperamental it had been, while reminiscing fondly about its foibles, but I was not that callsign I'm afraid.

I'm going to have a play with that formula though and see what it throws up. I assume it is the frequency in kilohertz, with the resultant antenna length in feet.

ETA: Just saw the follow-on post by @Helm with the antenna calculator. 234 divided by F in MHz +8 (Feet), gives a roughly 1/4 wavelength antenna, that would be tunable. Very good, but I prefer metres myself. I can mostly work it out quickly in my head, but who doesn't have a calculator to hand nowadays?

Further ETA: Just saw @Roadster280 post above ref tuning and totally agree. Smart lad he is, you should listen to him.

<<blushes>>

I was a mere Sgt. You on the other hand....

..let's just say I called you Sir, but not just because I had to. Some people command respect, others wear rank.

Here we are a long time later, and it's not changed...

Both of us know fvck all about Larkspur :D
 

seat_sniffer2

Old-Salt
What was wrong with clansman? I only caught the tail end of its service and apart from the size/weight it seemed alright. Certainly no worse than f***ing bowman

I actually picked up my Clansman ATE wagon & geny direct from Donny, early on in the changeover process, and then did a few years test & repair. The main VHF radio, 353 seemed to have been designed by a committee, and not a clever at that - you hearing me RARDE? I don't know if 'they' as an entity exist anymore? The 252 was a bit of a pain to work on, it was HF as I recall.

Met Racal Jaguar in another place, & it seemed a bit more efficiently modular

Did a bit with tropo in the same place, but it was early stuff & V large. A couple of stories there btw.
 
I actually picked up my Clansman ATE wagon & geny direct from Donny, early on in the changeover process, and then did a few years test & repair. The main VHF radio, 353 seemed to have been designed by a committee, and not a clever at that - you hearing me RARDE? I don't know if 'they' as an entity exist anymore? The 252 was a bit of a pain to work on, it was HF as I recall.

Met Racal Jaguar in another place, & it seemed a bit more efficiently modular

Did a bit with tropo in the same place, but it was early stuff & V large. A couple of stories there btw.

Totally agree. The 353‘s design committee obviously never met :)

As for HF 252s, that would be High Frequency boots. I quite enjoyed 252s, as long as they were someone else’s. Not much fun with your own 252. Expensive, Time consuming, or both. :D
 

itchy300

Old-Salt
I actually picked up my Clansman ATE wagon & geny direct from Donny, early on in the changeover process, and then did a few years test & repair. The main VHF radio, 353 seemed to have been designed by a committee, and not a clever at that - you hearing me RARDE? I don't know if 'they' as an entity exist anymore? The 252 was a bit of a pain to work on, it was HF as I recall.

Met Racal Jaguar in another place, & it seemed a bit more efficiently modular

Did a bit with tropo in the same place, but it was early stuff & V large. A couple of stories there btw.

Ahhhh I never had/used the 343, more of a 351/2 man myself. Always found them easy to use so maybe the committee got it right on that one :D
 
351/2 were good, simple bits of kit.
The 349 was pretty worthless.
The 320 was great.
 

seat_sniffer2

Old-Salt
351/2 were good, simple bits of kit.
The 349 was pretty worthless.
The 320 was great.
Ahh, the fog of time has now cleared a bit more for me...

Think I got my numbering mixed up a bit there. Thank you kindly for setting me right. Well, it was a long time past is my only excuse. Plus, all the alcohol in between.
 
Ahh, the fog of time has now cleared a bit more for me...

Think I got my numbering mixed up a bit there. Thank you kindly for setting me right. Well, it was a long time past is my only excuse. Plus, all the alcohol in between.
I mostly used manpack, so the Vehicle fit mostly escaped me.
At the time I was usually the lucky crow with the rubber serial killers gloves and apron topping up the batteries with acid and water.
 

itchy300

Old-Salt
351/2 were good, simple bits of kit.
The 349 was pretty worthless.
The 320 was great.

The 320 was above my level, the 349 was as you say pretty hopeless and binned off less company attacks and obua but the 351 was great, you could show someone how to use it in a couple of minutes and in modern lingo it was modular with the amp and plenty of options antenna wise.

Plus we only carried 1 in a patrol rather than 2 of the f***ing bowman, which is a 2 week course to learn to use
 

W21A

LE
Book Reviewer
351/2 were good, simple bits of kit.
The 349 was pretty worthless.
The 320 was great.
The 349 was a huge improvement over the A40, but in usual army 'that's to much of an improvement, lets spoil it' they gave it a throatmic headset which was awful.
 
Long time ago... I used to test & repair some of these memories, sighs Anyway:-

A40 - yeuch!
A41/42 ( differing freq ranges ), were man packs with solid non -recharge bty packs, supplying various voltages. They used small glass valves internally. You had to make sure they were well bedded into their sockets, with no bent pins!
A13 as I recall was a sort of manpack hybrid, as you could switch to PHASE modn for use in the jungle??
A43 ground to air etc. Really sh1t to repair - I remember all the little cans & special repair case?
B45/B47 - a step up veh mounted, again different freq ranges
C11/ C11 SSB - pain to work on. C13 the same.
C42/ C45 ok to work on as long, as you kept your fingers from the wrong place. I ended up with a few pinhole burns over time!
There was another monster, can't recall the nomenclature, might have been C150. Everyone tried to quickly slope shoulders when one of those turned up!

Then Clansman turned up, - pile of ****
The lower numbers (A41, B47, C42) were for infantry use, the higher numbers (A42, B48, C45) were for artillery use and had a lower frequency range and overlapped the other sets in the top 2Mhz. I worked on A41s for a year in NI and the biggest problem was the 4ft whip antenna socket which paddy soon found out that if they grabbed the antenna and pulled it, it snapped off at the base. It was a pig to take the front panel off to replace it so the 'unofficial' way was to lock the set upside down in a vice and use a big screwdriver and hammer to force the securing nut off. Cue lots of A41 securing nuts with big gouges out of them (I was REME, after all - these techniques are expected of us). These sets are all in the VHF range and are incapable of sending morse. One site I was sent out to was at (I think) Claudy where they had just set up an 8ft Yagi 'H' antenna and were complaining that they could not contact anyone. When I got there, I found that they'd set up the antenna on its side, wedged with sandbags, so one side was pointing up to outer space and the other side was trying to contact Australia! I advised them to mount the antenna vertically and went back to bed.

I never had to work on A13s but A14s were a different matter. This was specifically designed for ship to shore and the unit I was with in RM Poole (148 Bty) had loads of them. They were ok until the RN upgraded their shipboard comms to synthesised frequency control which meant that the A14s (which were notorious for frequency drift) found it difficult to work to the ships. For a unit that specialised in NGS, this was a pretty serious flaw. The solution was Her Majesty loosened the purse strings and bought a dozen Racal 931 sets which were synchronised and were excellent. Unfortunately, Royal found out that Perce had some radio kit that they didn't have and kicked up a fuss. The result was that Royal found we were only supposed to have 9 sets with 3 in reserve. So Royal snaffled those 3 and sent them down to Naval Party 8901 in the Falklands, where, presumably. the Argentinian Army snaffled them.

If anyone is labouring under the impression that the C45 is purely a vehicle mounted piece of kit, one of the BCs at Poole was as mad as a hatter and one of the bombardiers made the mistake of going into his office and saying that the guys had nothing to do. He hit the roof and told us to take a C45 up to Spetisbury Rings (local high point) and establish comms. The flaw in this argument is that when they are vehicle mounted, C45s have 2 big, heavy 12v batteries to supply the power. so 2 of us (me) manpacked a battery each and the rest of the party carried the C45, power supply and bits and pieces. I can assure you that a C45 battery plus manpack carrier (now no longer issued) weigh in excess of 120 pounds cos I had to carry it, Some good came out of it, at the end of the exercise, one of the matelots said we could all call ourselves FFR.
 

endure

GCM
The solution was Her Majesty loosened the purse strings and bought a dozen Racal 931 sets which were synchronised and were excellent.
Can you explain what you mean by 'synchronised' please?
 
Can you explain what you mean by 'synchronised' please?
It means that the frequency source is controlled by a crystal which generates a single rock solid frequency. All the other frequencies in the radios range are generated from this single source and are (usually) digitally counted up or down. Which is why most modern military radios do not have tuning knobs (a la Larkspur) but have a number of rotary switches on the front where you set up your required frequency (our Racals had them).
 

endure

GCM
It means that the frequency source is controlled by a crystal which generates a single rock solid frequency. All the other frequencies in the radios range are generated from this single source and are (usually) digitally counted up or down. Which is why most modern military radios do not have tuning knobs (a la Larkspur) but have a number of rotary switches on the front where you set up your required frequency (our Racals had them).
So synthesized then? I thought that synchronised might have a separate meaning. Cheers.
 

AlienFTM

MIA
Book Reviewer
If anyone is labouring under the impression that the C45 is purely a vehicle mounted piece of kit, one of the BCs at Poole was as mad as a hatter and one of the bombardiers made the mistake of going into his office and saying that the guys had nothing to do. He hit the roof and told us to take a C45 up to Spetisbury Rings (local high point) and establish comms. The flaw in this argument is that when they are vehicle mounted, C45s have 2 big, heavy 12v batteries to supply the power. so 2 of us (me) manpacked a battery each and the rest of the party carried the C45, power supply and bits and pieces. I can assure you that a C45 battery plus manpack carrier (now no longer issued) weigh in excess of 120 pounds cos I had to carry it, Some good came out of it, at the end of the exercise, one of the matelots said we could all call ourselves FFR.
I believe the C45 was the RA equivalent of the C42?

I'm told that RSMs before my time, when organising Ex Rat Race, the regimental JNCO Cadre course escape and evasion exercise, would set the situation that a crew would have started behind enemy lines in a knocked out tank, and the crew was to maintain comms during the E&E. By taking C42, batteries and harness "from the knocked out tank."

Pleased to report my RSM didn't do this. Especially since we E&Eed in 3-man "CVR(T) crews."

Phew.
 
So synthesized then? I thought that synchronised might have a separate meaning. Cheers.

In the Clansman era, they actually were “synchronised”, in effect. Obviously with frequency synthesis, you’re at the mercy of the accuracy of your crystal oscillator. On the ubiquitous 321 HF set for example, your minimum frequency adjustment on the front panel was 100Hz. So if you’re off by say 50Hz, that’s bad ju-ju, and the operator can’t do anything about it.

So the sets had a calibration regime, where they were calibrated against a Rubidium frequency standard. Or more usually, you checked the calibration of your frequency counter against the Rubidium jobby, and then used the frequency counter to check the sets. I never did I this in the field myself, it was usually done in 2nd line inspections, which was the responsibility of the regimental workshop, something I luckily managed to avoid. However, as an instructor, I did it quite a bit, and the accuracy/drift was pretty damned good for 1970s technology. I never saw a set more than a couple Hz off, and these were training sets that were absolutely shagged by years of trainee abuse.
 
D

Deleted 4482

Guest
In the Clansman era, they actually were “synchronised”, in effect. Obviously with frequency synthesis, you’re at the mercy of the accuracy of your crystal oscillator. On the ubiquitous 321 HF set for example, your minimum frequency adjustment on the front panel was 100Hz. So if you’re off by say 50Hz, that’s bad ju-ju, and the operator can’t do anything about it.

So the sets had a calibration regime, where they were calibrated against a Rubidium frequency standard. Or more usually, you checked the calibration of your frequency counter against the Rubidium jobby, and then used the frequency counter to check the sets. I never did I this in the field myself, it was usually done in 2nd line inspections, which was the responsibility of the regimental workshop, something I luckily managed to avoid. However, as an instructor, I did it quite a bit, and the accuracy/drift was pretty damned good for 1970s technology. I never saw a set more than a couple Hz off, and these were training sets that were absolutely shagged by years of trainee abuse.
Is it too early to ask of the OP...

Does he realise just what he has fecking started here...?!

:)
 

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